EUROPEANMATERIALS RESEARCH SOCIETY

Strasbourg (France)

E-MRS 2005 Spring Meeting May 31 – June 3, 2005

SYMPOSIUM E

Synthesis, characterization and applications of mesostructured thin layers

Symposium Organizers :

André Ayral, IEMM, Montpellier, France

Hugh W. Hillhouse, Purdue University, USA

Michaela Klotz, Saint-Gobain Recherche, France

Makoto Ogawa, Waseda University, Japan

Eduardo Ruiz-Hitzky, CSIC, Madrid, Spain

Papers to be published in Thin Solid Films

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E-MRS 2005 Spring Meeting

SYMPOSIUM E Tuesday, May 31, 2005 Morning Mardi 31 mai 2005 Matin Session I : Self assembling, self organizing layers, mesophase templating Session chairs : Bradley F. Chmelka and David Grosso E-I.01 8:30 -Invited- FORMATION OF MESOSTRUCTURED THIN FILMS AT THE AIR/WATER

INTERFACE Karen J Edler, Cristina Fernandez-Martin, Stephen J Roser Department of Chemistry,

University of Bath, Claverton Down, Bath, BA2 7AY, U.K. Mesostructured thin films are known to form at the interface between either air or a solid

surface and a dilute acidic solution containing the silica precursor, and surfactant template. These films are transparent, and, when grown at the air/solution interface, self supporting. We have been studying the formation processes of these films to try to understand and thus control the formation of both the mesoscale and the macroscale structure. The films are characterised using a variety of in situ methods including X-ray reflectivity techniques and Brewster angle microscopy, to study both the large and small scale structure development processes. As a result of our investigations we have suggested a coacervation driven mechanism for film growth and application of this understanding now drives our further development of these films. We will present results concerning the effect of surfactant headgroup type, structure and counterions on the development of well-organised mesostructures, and also on the macroscopic film characteristics.

E-I.02 9:00 -Invited- PHASE AND ORIENTATION CONTROL OF MESOPOROUS SILICA THIN FILM VIA

PHASE TRANSFORMATION Tatsuya Okubo(a,b), Sajo P. Naik(a,b) and Masaru Ogura(a), (a)Department of Chemical

System Engineering, The University of Tokyo and (b)PRESTO, JST, Bunkyo-ku, Tokyo 113-8656, Japan

Ordered mesoporous silica thin films have generated enormous interests for applications in photonics, optics and microelectronics. The traditional approach of fabricating the mesoporous silica thin films involves the cooperative self-assembly of organic structure-directing agent and inorganic precursors. Although cooperative self-assembly has been remarkably successful for the synthesis of ordered films with controlled pore sizes, it holds limited promise in mesophase structure and orientation controls.

We are interested in the phase and the orientation control of mesoporous silica thin films via phase transformation induced by external stimuli. The drying-induced phase transformation was first investigated in powder form, and a comprehensive view was proposed1). Based the view, we have developed a novel technique for fabricating oriented 3D mesoporous silica films over a large area via the phase transformation induced by the degradation of organic moiety. Our approach hinges on the first synthesis of flexible silica-surfactant mesophase by controlling the extent of silica condensation and correctly choosing a lytropic surfactant with a small head-group. The step-wise decomposition of the organics during high temperature calcination gradually brings about a change in the packing factor forwarding the phase transformation of the flexible silica mesophase into another structure. The as-synthesized films have p6mm hexagonal or lamellar structures, which are transformed to 3D cubic, such as Ia3d, Pm3n, etc. on applying the external stimuli, high temperature calcination in this case. The observed phase transformations have been characterized by combined TG-DTA-MS, in situ FTIR, temperature programmed XRD and TEM techniques. 1)M.Ogura et al.,JACS,126,10937(2004).

E-I.03 9:30 SYNTHESIS AND STRUCTURE OF ORTHORHOMBIC PHASE MESOPOROUS TIN

OXIDE THIN FILMS Hugh W. Hillhouse, Purdue University, USA A host of self-assembled mesoporous metal oxides thin films have been reported, including

several elucidating in depth studies on the TiO2 system [1]. However, despite the evolution of our understanding of these systems, well-ordered, thermally stable surfactant-templated mesoporous SnO2 films has remained elusive. Previously, researchers have reported disordered mesoporous SnO2 [2] as well as well-ordered non-porous mesostructures with p6m symmetry [3]. Here, we report the synthesis and characterization of highly ordered mesoporous tin oxide films having a orthorhombic Fmmm mesostructure that results from the anisotropic contraction of a parent Im3m phase. Films are prepared by dip-coating dilute solutions of triblock copolymer surfactants and tin oxide precursors. In contrast to SiO2 and TiO2 systems, the hybrid inorganic-organic films have no ordered mesostructure after dip-coating and are subsequently subjected to very high humidity at elevated temperatures. This delayed humidity treatment (DHT) induces the transition from a disordered amorphous hybrid to a highly ordered cubic mesostructure. The as-prepared films were then subjected to progressively higher temperatures to consolidate the inorganic framework. This thermal

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treatment is necessary to retain the mesostructure after surfactant removal and avoid structural collapse upon calcination.

[1] Crepaldi, EL, et al., J. Am. Chem. Soc. 125(32), 2003, 9770. [2] Qi LM, Ma JM, Cheng HM, Zhao ZG, Langmuir 14, 1998, 2579. [3] Miyata H, Itoh M, Watanabe M, Noma T.Chem. Mater. 15, 2003, 1334.

E-I.04 9:45 SELF ASSEMBLY OF OXIDE LAYERS G. Freiman(a,b), P. Barboux(a), J. Perrière(c), (a)LPMC, Ecole Polytechnique, 91128

Palaiseau Cedex, France, (b)STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex, France, (c)GPS, Université Pierre et Marie Curie, 4 Place Jussieu, Paris Cedex, France

Self-assembly chemistry offers a good method to obtain dense and high quality oxide films for dielectric applications as well as hybrid systems. Using a laboratory built automate in a controlled atmosphere, a silicon wafer was alternatively dipped in dilute solutions of Ti (or Zr) alkoxides, phosphoric acid, hydrolysis and catalysis solutions. Each sequence was followed by rinsing in order to graft one monolayer only and to activate the substrate for the following cycle. A linear increase of film thickness was observed upon increasing the number of deposition cycles. Formation of the coating and characterization of the surface termination were quantitatively followed by Wilhelmy-balance contact angle measurements, ellipsometry, X-ray reflectometry and Rutherford Backscatteing. Bidimensional titanium (or zirconium) phosphates as well as artificial sequences of alternate oxide layers of [(ZrO2)n /(TiO2)p]x have been synthesized on silicon by this sequential grafting method. We studied the effect of the periodicity of the ZrO2/TiO2 films on the physical properties.

The resulting films were characterized by capacity and current- voltage measurements in MIS structures gold/silicon/layer/gold electrode.

E-I.05 10:00 NON THERMAL PREPARATION OF FUNCTIONAL TITANIUM (IV) OXIDE THIN

LAYERS Petr Kluson(a), Hana Luskova(a), Tomas Cajthaml(b) and Olga Solcova(b), (a)Faculty of

Chemical Technology, Institute of Chemical Technology, ICT Prague, Technicka 5, 166 28 Prague, Czech Republic, (b)Institute of Microbiology, Academy of Sciences of the Czech Republic, Videnska 1083 142 20 Prague 4, Czech Republic

Self-assembly chemistry offers a good method to obtain dense and high quality oxide films for dielectric applications as well as hybrid systems. Using a laboratory built automate in a controlled atmosphere, a silicon wafer was alternatively dipped in dilute solutions of Ti (or Zr) alkoxides, phosphoric acid, hydrolysis and catalysis solutions. Each sequence was followed by rinsing in order to graft one monolayer only and to activate the substrate for the following cycle. A linear increase of film thickness was observed upon increasing the number of deposition cycles. Formation of the coating and characterization of the surface termination were quantitatively followed by Wilhelmy-balance contact angle measurements, ellipsometry, X-ray reflectometry and Rutherford Backscatteing. Bidimensional titanium (or zirconium) phosphates as well as artificial sequences of alternate oxide layers of [(ZrO2)n /(TiO2)p]x have been synthesized on silicon by this sequential grafting method. We studied the effect of the periodicity of the ZrO2/TiO2 films on the physical properties.

The resulting films were characterized by capacity and current- voltage measurements in MIS structures gold/silicon/layer/gold electrode.

E-I.06 10:15 MESOPHASES OF COLLOIDALLY DISPERSED NANOSHEETS PREPARED BY

EXFOLIATION OF LAYERED NIOBATES AND TITANATES Teruyuki Nakato, Institute of Symbiotic Science and Technology, Tokyo University of

Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588, Japan We prepared colloids of inorganic nanosheets by exfoliation of layered niobates and

titanates, and investigated their phase behavior in relation to the formation of lyotropic liquid crystals. Layered oxides investigated were hexaniobate K4Nb6O17, triniobate HNb3O8, titanoniobate HTiNbO5, and lepidocrocite-type titanate H1.07Ti1.73O4. They formed stable colloids in water through intercalation of organoammonium ions. The nanosheets were characterized by high anisotropy with lateral dimension of several micrometers and thickness (by assuming complete exfoliation) of around 1 nm.

All the nanosheet colloids became birefringent at certain concentrations, indicating formation of liquid crystalline phases. The colloids varied from isotropic to biphasic, and finally to liquid crystalline as the concentration of nanosheets increased. The transition concentrations were lower for the colloids consisting of larger nanosheets. This phase behavior was basically in accordance with Onsager's theory for entropy-driven transition of colloidally dispersed anisotropic particles. However, phase transition concentrations of the nanosheet colloids were depended on the oxides exfoliated. Less exfoliative HTiNbO5 and H1.07Ti1.73O4 gave higher transition concentrations. This fact indicates that the "real" phase behavior of the nanosheet colloids of niobates and titanates is largely affected by intrinsic chemical nature of each oxide although an "ideal" theoretical framework is given by Onsager theory.

10:30 BREAK

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Session chairs : Karen J. Edler and Philippe Barboux E-I.07 11:00 -Invited- VAPOR PHASE SYNTHESIS OF MESOPOROUS SILICA THIN FILMS Norikazu Nishiyama(a), Shunsuke Tanaka(a), Yoshiaki Oku(b), Yasuyuki Egashira(a), and

Korekazu Ueyama(a), (1)Osaka University, (b)ASET-MIRAI project, Japan Mesoporous silica films have conventionally been prepared by liquid deposition methods

such as epitaxial growth, spin-coating, and dip-coating. On the contrary, we have demonstrated a vapor phase synthesis to prepare ordered mesoporous silica films. In this method, the surfactant films were exposed to tetraethoxysilane (TEOS) vapor. We have found nano-phase transition of surfactant-silicate composites under vapor infiltration of TEOS. The phase transition of the nanocomposites under vapor infiltration implies their high mobility in the absence of solvent. The swelling of film thickness and d spacing was observed under vapor infiltration. In the vapor phase synthesis, selection of surfactant is the most important factor to determine the porous structure similarly to the sol-gel method. Mesoporous silica films with a channel structure were formed when quaternary ammonium brimide (CnTAB) was used as a surfactant. The pore channels run parallel to the substrate surface. When triblock copolymer was used as a surfactant, the silica thin films with two-dimensionally connected cage-like mesopores were formed. The mesostructured silica thin films have silicate layers with ordered pillars. The structure of pores of the films is of advantage for next-generation low-k films because the porous structure of the films is isotropic parallel to the film surface. The films show lower concentration of residual Si-OH group compared to the film prepared by a conventional sol-gel method. The films show high thermal stability up to 1200 K and high hydrothermal stability. The vapor-phase synthesis can be applied for organic-inorganic nanocomposites and mesoporous metal oxides other than silica and provides opportunities for the creation of new materials technologies.

E-I.08 11:30 CROSS-LINKED POLY(STYRENE-block-2-VINYLPYRIDINE) THIN FILMS AS

SWELLABLE TEMPLATES FOR MESOSTRUCTURED SILICA AND TITANIA B.F. Chmelka, R.C. Hayward, E.J. Kramer, Department of Chemical Engineering,

University of California, Santa Barbara CA 93106, USA Mesostructured inorganic films can be prepared by using block copolymers that are

processed as pre-organized template films into which a network-forming sol-gel solution is selectively incorporated. This approach often allows greater control of mesophase orientation and long-range ordering in product films, compared to processes in which the block copolymer and inorganic components are co-assembled simultaneously. Depending on the crosslink density and film thickness, however, such swelling can disrupt mesoscopic ordering of the template film and produce macroscopic film wrinkling, due to instabilities induced by large osmotic stresses. For the case of amphiphilic PS-b-P2VP films, partial cross-linking of the P2VP component allows mesoscopic ordering and macroscopic morphologies of swelled films to be preserved during infiltration by network-forming sol-gel species. The optimal extent of P2VP cross-linking depends on the thickness of the template film and is crucial for the film to swell affinely without undesirable disorganization or wrinkling. Results will be presented that examine the key physicochemical variables and processing considerations necessary for preparing inorganic-organic and mesoporous silica and titania thin films with high extents of microdomain alignment, long-range ordering, and surface patterning.

E-I.09 11:45 A GENERAL APPROACH TO SINGLE OXIDE AND MULTIMETALLIC OXIDE

NANOCRYSTALLINE MESOPOROUS ORDERED LAYERS David Grosso, Cédric Boissière, B. Smarsly, M. Antonietti, Clément Sanchez, Chimie de la

Matière Condensée, UMR UPMC-CNRS 7574, 4 place Jussieu, 75252 Paris 05, France Despite its importance in many application domains, silica based mesoporous films cannot

compete with the richness of physico-chemical properties associated to amorphous and crystalline metal oxide mesoporous materials. In the present work, we describe a general approach to the preparation of highly ordered mesoporous layers composed of pure nanocrystalline frameworks such as photoactive Anatase TiO2 and tetragonal MgTa2O6, stable -Al2O3, spintronic Illmenite CoTiO3, and ferroelectric Perovskite SrTiO3. Integration of such systems into devices requires a perfect tuning of particle and pore respective dimensions in the desired mesoorder. In situ time resolved SAXS - WAXS analyses, involving synchrotron high flux, were used to assess the various phenomena involved during deposition, thermal treatment and crystallisation. Critical chemical and processing parameters, affecting the self-assembly, are discussed and a general model based on a Modulable Stady State is proposed. We show that depending on the heating regime, ordered mesoporous nanocrystalline frameworks can be obtained through a rigorous control of the various steps involved in the stabilisation of the inorganic network (i.e. dehydration, template thermal decomposition, inorganic nucleation, growth and diffusive sintering). Meso and microstructures were confirmed by TEM and HRTEM analyses. Finally, the porosity and pore size distribution of these layers were assessed using ellipsometric porosimetry.

E-I.10 12:00 STRUCTURE AND FIELD INDUCED PHASE TRANSITION IN MONOLAYERS OF

FUNCTIONALIZED HEXA-PERI-HEXABENZOCORONENES L. Piot, A. Marchenko, D. Fichou, CEA-Saclay, Labo Nanostructures et Semi-Conducteurs

Organiques (CNRS-CEA-UPMC), SPCSI/DRECAM, 91191-Gif sur Yvette, France and J. Wu, K. Müllen, Max-Planck-Institut für Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

The recent advances in the field of organic molecular electronics have given an increasingly important role to polycyclic aromatic hydrocarbons with peripheral substituents. These liquid crystals consist of rigid flat cores surrounded by flexible chains, which enable them to form columnar mesophases. One-dimensional transport of charge-carriers along those nano-

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columns is of prior interest for applications such as organic transistors or photovoltaic organic cells.

We will describe here the self-assembly properties of a family of functionalized hexa-peri-hexabenzocoronenes (HBC) deposited on highly ordered pyrolitic graphite (HOPG) and Au(111) substrates. We characterised these systems in situ by mean of scanning tunnelling microscopy at the liquid-solid interface using n-tetradecane as a solvent. Functionalized HBC-molecules were found to form long range ordered monolayers on HOPG (up to 500 nm) with molecules lying flat on the surface, while on Au(111) the size of ordered domains does not exceed 50 nm. Furthermore, on HOPG, the increase of the electrical field in the tunnelling gap leads to the formation of columnar phases on top of the first layer. This field induced phase transition was found to be reversible allowing the control of film structure at the nano-scale level.

E-I.11 12:15 VERY HIGH PHOTOREFRACTIVE OPTICAL GAIN AND COOPERATIVE EFFECTS

OF AMORPHOUS BLENDS BASED ON POLY-N-VINYLINDOLES A. Colligiani, Dept. of Food Science, University of Napoli “Federico II”, 80055 Portici (Na)

and INFM, Italy; F. Ciardelli, F. Greco, G. Ruggeri, Dept. of Chemistry and Industrial Chemistry, University of Pisa, 56126 Pisa and INFM, Italy; M. Angiuli, E. Tombari, Istituto per i Processi Chimico-Fisici, CNR, 56124 Pisa, Italy

In previous studies[1]we have verified that indole group and some of its derivatives(in particular the 2,3-dimethyl one) are characterized by good values of the photoconductivity. In this communication we report the results of photorefractivity measurements that we have accomplished on 25 µm -thick films. A derivative of 2,3-dimethylindole, namely the 3-[2-(4-nitrophenyl)ethenyl]-1-(2-ethylhexyl)-2-methylindole (NPEMI-E), was synthesized and employed. When mixed with the photoconductive poly-(N-vinyl-2,3-dimethylindole)(PVD), it can give photorefractive blends. It has been verified that high values of the photorefractive optical gain Г can be measured. In particular, when the percentage of NPEMI-E is of the order of 90%, a maximum of the Г value is obtained that amounts to about 1000. This behaviour seems to show that a cooperative effect is active in these blends, due to the electrostatic interactions among the NLO molecules, having also a very high value of the electric dipole moment μ. It has been recently shown[2]that for particular relative geometries and values of the intermolecular distances (and hence of the concentration), the α and β components of the polarizability (that control the entity of the photorefractivity) can attain a net maximum. The presence of a high static electric field also supports the molecular reorientation (birefringence contribution to the photorefractivity) and the cooperative effect. The two effects together allow to describe the material as a self-assembling one through the optimization of the electrostatic interactions.

[1]R.Angelone, C.Castè, V.Castelvetro, F.Ciardelli, A.Colligiani, F.Greco, A.Mazzotta, G.Ruggeri, e-Polymers, n. 075 (2004). 2]F.Terenziani, A.Painelli, Phys. Rev. B, 68, 165405 (2003).

E-I.12 12:30 SELF ASSEMBLED FILMS OF NON PLANAR PHTHALOCYANINES ON III-V

SEMICONDUCTORS Nicolas Papageorgiou, Eric Salomon, Thierry Angot, Universite de Provence, PIIM UMR-

CNRS 6633, France We will focus on the structural arrangements of sub-monolayer up to few monolayer thin

films of non-planar phthalocyanines adsorbed on narrow band gap III-V semiconductors, as seen in scanning tunneling microscopy as well as on chemical and electric properties, as studied by high resolution synchrotron radiation photoelectron spectroscopy, near-edge X-ray absorption spectroscopy and energy loss spectroscopy. Special emphasis will be given to the universal character of adsorption of the non-planar phthalocyanines where the central atom is either lead or tin. The latter molecules form ordered superstructures on the indium rich 4x2/c(8x2) reconstruction of the InSb(100) and InAs(100) surfaces. Comparison with metal free and metal substituted planar phthalocyanines (H2Pc, CuPc, CoPc...) adsorbed on semiconductors or noble metal surfaces will be also presented.

12:45 LUNCH

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Tuesday, May 31, 2005 Afternoon Mardi 31 mai 2005 Après-midi Session II: Template synthesis of mesostructured functional layers: in situ growth of nanoparticles, nanowires, interconnected networks Session chairs : Hugh W. Hillhouse and Tatsuya Okubo E-II.01 14:00 -Invited- ORDERED AND DISORDERED 1D ARRAYS WITHIN NANOPOROUS OXIDE FILMS M. Hernández-Vélez, Applied Physics Department, C-XII, Autónoma University / Materials

Science Institute from Madrid (CSIC). Carretera de Colmenar KM. 15 Km., Cantoblanco 28049 Madrid, Spain

Since the discovery of M41S materials family in 1992 thin films of these materials with features like, aligned pores perpendicularly to the substrate surface and long range order, have been looked for with great interest. Although the growth of continuous oxide thin films on different surfaces is a well known issue, the growth of those films displaying meso- and nano-porous structures have focalised the attention in the last decade and, with that objective, several techniques such as: MBE, CVD, AFM, etc. have been used. Recently “down – top” techniques particularly those in which, self-assembly processes play a relevant role in the growth mechanisms of that nanostructures have been reported. Among them Electrochemical techniques constitute one of the most used for making highly ordered nanostructures to be used as templates for growing replicated nanostructures, as well as, to obtain enhanced qualities and applications based on previously designed functionalization. Upon the obtained results along the latest ten years, in this paper, some insights prevailing in the fabrication processes of nanoporous Silica thin films obtained by electron beam evaporation of MCM-41 and, nanoporous Alumina (AAM) and Titania (ATM) membranes obtained by anodization of Aluminium and Titanium foils respectively are discussed. In addition, we show some results on ordered and disordered functional materials such as, magnetic and semiconductor nanowire arrays, biosensors and carbon nanotubes obtained within AAM and ATM used as templates. The potentiality of the techniques used and materials obtained for magnetic, magneto-optic, biotechnology and optoelectronic applications is demonstrated.

E-II.02 14:30 -Invited- INTEGRATED CHEMICAL SYSTEMS BUILT USING NANOPOROUS

GLASS/CERAMICS AS SUBSTRATES Oswaldo Luiz Alves, Italo Odone Mazali and Ricardo Romano, Solid State Chemistry

Laboratory – LQES, Institute of Chemistry – UNICAMP, Brazil Nanostructured semiconductors materials have been subject of intense investigation due to

their remarkable properties when compared with bulk counterparts. It is well known that nanocrystals exhibit great instabilities associated with their high surface energy. In this concern, nanocrystals growth inside the cavities of a porous host becomes an attractive integrated chemical system (ICS) because certain processes can be performed in a restricted environment were porous act as nanoreactors. In this work we report the synthesis and characterization of nanosized semiconductor oxides (TiO2, SnO2, Nb2O5, Fe2O3) and sulfides (CdS, PbS) dispersed into porous Vycor glass (PVG) and NbPO5 porous monoliths via impregnation-decomposition cycles (IDC) of single-source precursors. After a series of ten consecutive IDC, the XRD, Mössbauer and Raman data confirmed the "in situ" formation of nanosized TiO2 (anatase), SnO2, T-Nb2O5, Fe2O3, CdS, and PbS. It was verified the formation of crystals smaller than that obtained for "as cast" precursors decomposition and also that nanocrystals growth is a linear function of the mass increment being independent on the time of the thermal treatment for both porous substrates studied. TEM bright and dark field images of PbS/PVG reveal guest particles showing maximum diameters near 20 nm, exactly the maximum dimensions of the glass pores. By combining physical (space restriction) and chemical (anchoring) properties, the integrated system plays a fundamental role in preventing the coalescence process thus allowing the control of the nanocrystal size via a linear mass increment. In addition, factors as the absence of solid-state reactions, and the preservation of the porous structure make possible using ICS in catalytic process and gas sensoring.

E-II.03 15:00 PREPARATION AND OPTICAL PROPERTY OF ZnO ELECTROCHEMICALLY

DEPOSITED IN MESOPOROUS SILICA FILMS Feifei Gao, Sajo P. Naik and Tatsuya Okubo, Department of Chemical System Engineering,

the University of Tokyo and PRESTO, JST, Bunkyo-ku, Tokyo 113-8656, Japan and Yukichi Sasaki, Japan Fine Ceramics Center, Atsuta-ku, Nagoya 456-8587, Japan

Being a large direct-bandgap semiconductor, zinc oxide has been widely paid attention, and nano-sized zinc oxide presents unique properties because of the quantum size effect. Meosporous silica films have been investigated as novel templating materials with various nanostructures [1]. In this present work, dip-coated mesoporous silica films [2] on a substrate of conductive Pilkington TEC Glass(r) were employed as a template, and an electrochemical deposition method was applied for the preparation of ZnO nanoparticles. The ZnO-deposited mesoporous silica (ZnO/MPS) films were characterized by XRD, EDS, SEM and TEM measurements. Photoluminescence of ZnO/MPS was observed at room temperature, which showed three main emitting peaks at 451.5, 415 and 369 nm. The emission peak at 369 nm presented apparent blue-shift compared with that at 384 nm from bulk ZnO. The corresponding bandgap of ZnO nanoparticles significantly increased compared with that of bulk ZnO.

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[1] Y. Murakami, S. Yamakita, T. Okubo and S. Maruyama, Chem. Phys. Lett. 375 (2003) 393 [2] S. P. Naik, S. Yamakita, Y. Sasaki, M. Ogura, and T. Okubo, Chem. Lett. 33 (2004) 1078

E-II.04 15:15 TUNED PHOTOLUMINESCENCE EMISSION OF CDS DOTS EMBEDDED IN

MESOPOROUS SILICA V. Della Savia(a), M.C. Marchi(a), E. Otal(a), P. Bozzano(b), G. Soler-Illia(b), S.A.

Bilmes(a), (a)Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, DQIAQF-INQUIMAE; Ciudad Universitaria Pab. II (C1428EHA) Buenos Aires, Argentina; (b)Unidad de Actividad Química and Unidad de Actividad de Materiales, CNEA, Centro Atómico Constituyentes, Avda. Gral. Paz 1499, (B1650KNA) San Martín, Buenos Aires, Argentina

Mesoporous silica films synthesised with different surfactants are used as templates for nucleation and growth of CdS nanoparticles by impregnation in aqueous Cd2+ and S2- solutions. The presence of crystalline CdS nanoparticles within the silica matrix was confirmed by DRX and TEM/SAD/EDS.

The photoluminescence emission of CdS in these composites exhibits a narrow excitonic band at ca. 2.6 eV and a broad band in the 2.2-1.9 eV range due to radiative decay of excited surface states. The emission of CdS dots in these silica films is stable for several months. Effects in the position and relative intensity of the excitonic and surface state bands are observed when the mesoporous film is synthesised with CTAB, F127 or Brij 58. CdS nanoparticles included within mesoporous films obtained with CTAB show higher excitonic emission as the CTAB/Si ratio in the precursor silica sol decreases. The main conclusion of this work is that the blue emission of CdS dots can be enhanced by quenching the emission of surface states with appropriate control of the chemistry of the inorganic walls interacting with CdS nanoparticles.

E-II.05 15:30 FERROELECTRICS TEMPLATED IN NANOPOROUS ALUMINA MEMBRANES E.D. Mishina, N.E. Sherstyuk, K.A. Vorotilov, V.A. Vasil’ev, A.S. Sigov, Moscow State

Institute of Radioengineering, Electronics and Automation, Moscow, Russia; Th. Rasing, IMM Institute, University of Nijmegen, Nijmegen, The Netherlands; M.P. De Santo, R. Barberi, Universita’ della Calabria, Rende, Italy

We show that, similar to the well-known metal and semiconductor nanostructures, ferroelectric nanostructures also can be prepared by templation technique for a variety of applications: nano-electromechanical systems, pyroelectric detectors, memory capacitors, photonic crystals. We report here the fabrication and the structural and optical characterization of the ferroelectric perovskites PbZrTiO3 and BaSrTiO3, embedded by the sol-gel technique into nanoporous alumina membranes with a pore size of 50-200 nm. The surface topography and crystallographic structure of the porous substrates and nanostructures were studied by AFM and SEM. To distinguish between paraelectric and ferroelectric phases, optical second harmonic generation was applied. Penetration of precursor and filling of the pores depend on the porous size. For porous diameter >100 nm, hollow rods (tubes) and for smaller pores, filled rods are formed. Although the obtained rods are polycrystalline, they possess ferroelectric properties and a strong increase of optical second harmonic generation after annealing.

E-II.06 15:45 ELABORATION OF MACROPOROUS CARBON FILMS FROM COLLOIDAL

CRYSTALS Stéphane Reculusa(a), Pascal Masse(a), Alain Derré(a), Michel Couzi(b), Pierre Delhaès(a),

Serge Ravaine(a), (a)CRPP-CNRS, Av. A. Schweitzer, 33600 Pessac, France, (b)LPCM, Université Bordeaux 1, 33405 Talence, France

Template-directed syntheses have been broadly applied to the creation of macroporous ceramics and polymers. The extension of such methods to carbons is of particular interest. Carbon crystals containing large internal surface areas could be used in numerous applications, ranging from electrochemical sensors to membranes. The goal of this work is to prepare macroporous carbon crystals with a well-controlled thickness. First, opals of monodisperse silica spheres have been elaborated using the Langmuir-Blodgett technique. In fact, successive transfers onto a solid substrate of pre-organized two-dimensional arrays of submicrometer silica particles at a gas/liquid interface allow the formation of three-dimensional colloidal crystals with a perfectly controlled number of layers. Opal carbon replicas are then produced by infiltrating into the porous matrix of synthetic opals by the chemical vapor deposition (CVD) method of methane gas and removing silica spheres by hydrofluoric acid. Carbon replicas exhibit both a well-defined thickness and cavities which match the size of the starting silica colloids and retain their close-packed ordering. Besides these carbon replicas were treated at 2500°C for 1.5 hours under a neutral atmosphere. The hydrocarbon microstructure has been investigated thanks to Raman spectroscopy. In particular, it has been shown that the intensity ratio between the so-called "D and G" lines is different before and after the heat treatment, indicating a structural change for these carbon films.

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Session III : Lamellar and nanoporous materials layers : lamellar silica and silicates, layered metal oxides and chalcogenides, zeolites… Session chairs : Imre Dekany and Makoto Ogawa E-III.01 16:30 -Invited- HIGH-Tc SUPERCONDUCTING THIN FILM FROM BISMUTH CUPRATE NANO-

COLLOIDS Jin-Ho Choy, Intelligent Nanohybrid Materials Laboratory, Division of Nanoscience and

Department of Chemistry, Ewha Womans University, Korea A systematic application of intercalation technique to layered superconducting oxides

enables us to open a new chapter in the development of nano-hybrid with various functions. Recently, we were successful in preparing a novel high-Tc superconducting micro-wires and films from the nano-hybrid exfoliated superconducting colloid by electrophoretic deposition method (EPD). In order to prepare colloidal suspension, the high-Tc bismuth cuprate superconductor, Bi2Sr2CaCu2O8+y or Bi2Sr2Ca2Cu3O10+y, should first be intercalated with mercury iodide molecules and subsequently with organic salt intercalates. Exfoliation of Bi-based superconductor has been achieved from organic salt intercalates. We found that the surface charge of the resulting nanosheets in acetone solvent is slightly positive with a potential of 25mV, which allowed us to apply these colloidal particles as a novel precursor to the fabrication of superconducting thin films. As a great advantage, the present exfoliated nanoparticles are not limited to shape and scale of substrate due to its nanoscale dimension. As a point of this view, high-Tc superconducting thin films and micro-wires on silver substrate were fabricated by EPD method. Directional growth along c-axis and connectivity between grains were remarkably improved by subsequent heat treatment. Consequently, the resulting films and wires show reasonable critical current density (Jc) and their thickness can be controlled in proportion to the regulation of time.

E-III.02 17:00 Ni COLLOIDS-LDH NANOCOMPOSITES AS PRECURSORS OF CATALYSTS D. Kostadinova, N. Sanson, C. Gérardin, D. Tichit, Laboratoire de Matériaux Catalytiques et

Catalyse en Chimie Organique, UMR 5618 CNRS-ENSCM-UM1, Institut C. Gerhardt FR 1878, 8 rue Ecole Normale, 34296 Montpellier Cedex 5, France

Layered Double Hydroxides nanocomposites have been prepared as precursors for the obtention of metal particles of controlled sizes embedded in a layered structure. Such materials should exhibit interesting catalytic properties, particularly as selective hydrogenation catalysts. With this aim Mg/Al LDH are used as host structures for guest Ni-based colloids. Suspensions of Ni hydroxide nanoparticles are priorily prepared by controlled hydroxylation of Ni2+ ions using citrate anions as strong complexing agents in order to ensure particle growth control. Three different procedures have then been followed to prepare the nanocomposites and have been compared: i) the so-called templating method, i.e. coprecipitation of the LDH in the presence of the colloidal suspension of particles; ii) anionic exchange of the initial compensating anions of the LDH with the nanoparticles; iii) reconstruction of calcined LDH in the presence of the colloidal suspension of nanoparticles. The anionic exchange allows to obtain the most organized nanocomposite structure. In a second step reduction treatments have been optimised in order to avoid, on one hand, the destruction of the host layered structure, and on the other hand, the aggregation and growth of metal particles. This has been achieved by thermal treatments under inert atmosphere, benefiting from the decomposition of the hydrogen-containing citrate species, or by performing treatments with strong reducing agents.

E-III.03 17:15 COATING OF REACTIVE METAL OXIDE DERIVED FROM Mg-Al LAYERED

DOUBLE HYDROXIDES ON CERAMIC SUBSTRATE Pankaj Bharali(a), André Ayral(b) and Rajib L. Goswamee(a), (a)Material Science Division,

Regional Research Laboratory (CSIR), Jorhat-785006, Assam, India, (b)Institut Européen des Membranes, UMR n° 5635 CNRS-ENSCM-UMII, CC047, Université Montpellier II, Place E. Bataillon, 34095 Montpellier Cedex 5, France

Highly thixotropic aqueous dispersions formed by positively charged layered double hydroxides (LDH) and negatively charged montmorillonites can be deposited as thin layers on ceramic supports. After thermal treatment, such composite coatings can give rise to layers of highly reactive supported oxides having potential of applications as efficient catalysts or adsorbents for toxic gases. In the present study, Mg-Al layered double hydroxide is synthesized and composite coatings are deposited on ceramic honeycomb monoliths. The rheological behavior of the starting dispersions is investigated. Crack-free coatings with tunable thickness can be obtained by controlling the viscosity of the dispersions. The thermal and structural evolution of the coatings is studied. Preliminary results concerning the application of the coated monoliths for the reversible chemisorption of sulfur dioxide is finally presented.

E-III.04 17:30 INTERCALATED HALOGEN MOLECULES AS RADIATIVE CENTERS IN

TRANSITION METAL DICALCOGENIDES LAYERED CRYSTALS D. Dumchenko, C. Gherman, L. Kulyuk, Institute of Applied Physics, Chisinau 2028,

Republic of Moldova; E. Fortin Department of Physics, University of Ottawa, Ontario K1N 6N5, Canada; E. Bucher, Department of Physics, University of Konstanz, P.O. Box X916, 78457 Konstanz, Germany

Owing to their layered structure the transition metal dichalcogenides (TX2), can be intercalated with foreign atoms and molecules. In this work the study of the radiative properties of MoS2, WS2 and WSe2 compounds intercalated by halogen molecules is presented.

The single crystals were grown by chemical vapor method, using iodine, bromine and chlorine as a transport agents. It is shown that the observed strong IR photoluminescence (PL) of these indirect band-gap semiconductors are produced by bound excitons related to

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the transport agent, intercalated in 2H-TX2 crystals during the growth process. The diatomic halogen molecules, positioned in the well defined interstitial sites of the van der Waals gap, give rise to the neutral centers, located at energy 0.1eV below the conduction band, with properties similar to that of isoelectronic traps in Si or GaP, providing an efficient radiative recombination. The temperature evolution (T=2-150K) of the excitonic emission spectra, the thermal quenching processes and the temperature dependence of the radiative decay time are described in the framework of a kinetic model assuming quasiequilibrium conditions.

E-III.05 17:45 COMPARISON OF BLTO FILMS DEPOSITED BY MAGNETRON SPUTTERING AND

PULSED LASER DEPOSITION M.P. Besland(a), H. Djani-ait Aissa(b), P.R.J. Barroy(a), P.Y. Tessier(a), B. Angleraud(a),

M. Richard-Plouet(a), L. Brohan(a) and M.A. Djouadi(a) (a)Institut des Matériaux Jean Rouxel, UMR 6502, 2 rue de la Houssinière, B.P. 32229, 44322, Nantes cedex 3, France, (b)Division milieux Ionisés et lasers, Centre des Technologies Avancées CDTA, Baba Hassen Alger, Algérie

The Aurivillius phase Bi3.25La0.75Ti3O12 (BLT0,75), have been recently explored in our institute as substituting materials for PZT [1], thanks to its high-fatigue resistance, larger remanent polarization and low processing temperatures compatible with Si-based technology. BLTO is more promising than SBT in view of its lower processing temperature and higher remanent polarization [2]. Among published results, fatigue-free BLT films have been grown on Pt/Ti/SiO2/Si substrates using various methods like pulsed laser deposition, MOCVD or sol-gel methods.

In this work, after the synthesis of BLTO powder and sintering of 2" targets, BLTO films were deposited by magnetron sputtering and pulsed laser deposition (PLD), using a mixture of argon and oxygen atmosphere, in a pressure range of 5-50 mTorr and a deposition temperature ranging from RT to 550°C. In a first step, the physico-chemical properties of thin films, with thickness ranging from 100 nm to 1µm, were characterized by XRD, AFM, XPS, SEM and EDXS. In a second step, electrical characterizations were performed on Si/SiO2/TiO2/Pt/BLTO/Pt structures. In this paper, we investigate and compare for the two deposition techniques, the effects of deposition parameters and annealing conditions on the physico-chemical properties of the BLT films, i.e. chemical composition, crystalline structure, optical properties and finally electrical properties. In addition, the effect of substrate with a nanostructured network as carbon nanotubes or nanoporous SiO2 templates are investigated. [1] M.W. Chu, M. Ganne, M.T. Caldes, L. Brohan, J. Appl. Phys. 91,3178 (2002). [2] BH Park et al., Nature, 401,682 (1999).

E-III.06 18:00 MICROWAVE SYNTHESIS OF ZEOLITE MEMBRANES BY DIRECT OR

SECONDARY GROWTH J. Motuzas(a,c), A. Julbe(a), R.D. Noble(b), Z.J. Beresnevicius(c), (a)Institut Européen des

Membranes (UMR CNRS 5635), UMII, CC47, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France, (b)University of Colorado, Chemical & Biological Engineering Dept., UCB 424, Boulder, CO 80309, USA, (c) Kauno Technologijos Universitetas, Organines Chemijos Katedra, Radvilenu pl. 19, 50299 Kaunas, Lithuania

The preparation of zeolite membranes with controlled microstructure, quality, thickness and composition is desirable for a number of applications such as pervaporation, gas separation and catalytic reactors. On the other hand, the development of efficient, reproducible and low cost synthesis methods are required for industrial development of this new and promising generation of inorganic membrane. We recently investigated MWs for limiting the synthesis duration and improving the characteristics of zeolite membranes. This presentation reports our recent results on MW derived zeolite membranes (e.g. SOD, MFI) obtained either by direct growth or by secondary growth of a layer of MW derived seeds deposited on or in an aAl2O3 support. Depending on the synthesis conditions, either infiltrated composite membranes or thin supported layers can be obtained. The membrane structure, crystal orientation and thickness are directly related to the synthesis parameters (starting sol composition, seeding conditions, MW power, synthesis temperature, duration ...). By a proper selection of the synthesis conditions, zeolite membranes with attractive performance in gas separation or pervaporation can be prepared within a few hours.

E-III.07 18:15 A LOW TEMPERATURE OZONE ACTIVATION PROCESS FOR PREPARING HIGH

QUALITY ZEOLITE MEMBRANES Samuel Heng(a), Prudence Pui Sze Lau(a), King Lun Yeung(a), Malik Djafer(b) and Jean-

Christophe Schrotter(c), (a)Department of Chemical Engineering, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P.R. China, (b)Veolia Water Hong Kong, 22/F, 8 Queen’s Road Central, Hong Kong, P.R. China, (c)Anjou Recherche, Veolia Water Research Center, Chemin de la Digue, BP 76, 78603 Maisons-Laffitte Cedex, France

The effectiveness of low temperature ozone treatment for organic template removal from MFI zeolite membranes was investigated. The aim is to establish a convenient and reliable method for zeolite membrane activation that will ensure not only high gas permselectivity but also more importantly, good reproducibility - since the commonly used high temperature activation methods may result in crack formation. The effects of ozone concentration, treatment temperature, membrane thickness and compositions on the treatment process were examined. It was found that half an hour treatment in oxygen mixture containing 50 g/m3 of ozone at 473 K is sufficient to remove all organic templates from 2-?m MFI zeolite membranes. However, longer treatment time is needed for thicker membranes and for ZSM-5 with high aluminum concentrations. Membranes with excellent gas permeance and permselectivity were consistently obtained using this treatment method. In addition, the membranes treated by ozone exhibit more reproducible membrane properties than calcined membranes. This work clearly demonstrates that low temperature ozone treatment is an effective method for removing organic template molecules from zeolite membranes. The ozone treatment method can be easily scaled-up for commercial production of zeolite

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membranes. The low temperature operation simplifies the equipments design and the shorter activation time at low temperature results in a significant reduction of the membrane production cost.

E-III.08 18:30 SELF-SUPPORTED POLYELECTROLYTE MULTILAYER THIN FILMS OBTAINED

BY DISINTEGRATION OF PH-RESPONSIVE LAYERS UNDER PHYSIOLOGICAL CONDITIONS

Shoko S. Ono(a,b), Gero Decher(a,c), (a)Institut Charles Sadron, 6 rue Baussingault, 67083 Strasbourg , France, (b)R&D Center, Mitsui Chemicals, Inc, 580-32, Nagaura, Sodegaura, Chiba 299-0265, Japan, (c)Université Louis Pasteur, Faculté de Chemie, 4 rue Blaise Pascal, 67000 Strasbourg, France

Thin films with multimaterials arranged with nanoscale precision have great potentials for facilitate integration, miniaturisation and multifunctionalisation of the devices. "Layer-by-layer deposition" permits to fabricate multilayer films consist of various materials arranged with nanoscale precision on almost any substrate. If the multimaterial film can be released from the substrate, the obtained self-supported multimaterial films open a wider field of applications, for example membrane separation, catalysis and so on. However, the methodology of releasing of those multimaterial films without deteriorations of their properties has not yet established enough.

We developed a new system to obtain self-supported multimaterial films under physiological conditions. In this system, the pH responsive multilayers formed via hydrogen-bonds which cover substrate surface play the key role to release the polyelectrolyte multilayer films constructed onto the pH responsive multilayers. In the presentation, the main principle of the new system, the key factor for releasing the self-supported films and structural features of self-supported multimaterial films will be discussed. (1,199 characters)

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Wednesday, June 1, 2005 Afternoon Mercredi 1er juin 2005 Après-midi Session IV : Composite and hybrid layers Session chairs : Eduardo Ruiz-Hitzky and André Ayral E-IV.01 14:00 -Invited- MOLECULAR DESIGN OF MESOPOROUS NANO-STRUCTURED INORGANIC AND

HYBRID ORGANIC-INORGANIC MATERIALS Clément Sanchez, Cédric Boissière, David Grosso, Lionel Nicole, Laboratoire de Chimie de

la Matière Condensée, Université Pierre et Marie Curie, 4 Place Jussieu, Tour 54, 75252 Paris, Cedex 05, France

Hybrid nano-composites materials can be obtained either through hydrolysis and condensation reactions of functional metal alkoxides or chlorides or through the assembly of well defined nanobuilding blocks. The properties that can be expected for such materials of course depend on the chemical nature of their components but also on the extend and the nature of their interface. This interface can also be tuned with or without templates to built nano-structured hybrids or even nanostructured metallic oxides. The control of the surface properties of the inorganic nano-building bricks by using nucleophilic groups carried by texturing agents triggers the obtention of a given nano-phase. Considerable effort is being currently directed to the obtention of nanostructured oxides. The use of ordered lyotropic phases as templating agents (surfactants, organogels, bio-polymers), leading to a mesoscopically ordered hybrid precursor allow the obtention of long-range nanostructured hybrid or metal oxide phases shaped as bulks or films. Some examples concerning the design of hybrid materials made by using, metal alkoxides precursors or nano-building bricks, to create mesoscopically ordered phases will be presented together with some of our results concerning materials having hierarchical structures. Hybrid Meroporous sensors and catalysts and new mesoporous films made of nanocrystalline multimetallic metal oxides (SrTiO3, BST, MgTa2O6 CoxTiO2, ....) will be also described. Some references C.Sanchez and F. Ribot, New Journal of Chemistry, 18, (1994),1007. E. Scolan; C. Magnenet; D. Massiot; C. Sanchez, J. Mater. Chem., 1999, 10, 3217 G. Soler-Illia, L. Rozes, M.K. Boggiano, C. Sanchez, C-O. TSrrin, A-M. Caminade, J-P. Majoral, Angewandte Chemie, 39,23 (2000), 4249. G. Soler-Illia, E. Scolan, A. Louis, P.A. Albouy, C. Sanchez, New Journal of Chemistry.(2001), C. Sanchez and B. Lebeau, MRS Bulletin, (2001), 26 (5), 377. E. Crepaldi,G. Soler-Illia, D. Grosso, PA Albouy and C. Sanchez, Chem. Comm, 2001, 1582. D. Grosso, G. Soler-Illia, F. Babonneau, C. Sanchez, PA Albouy , A. Brunet, A.R. Balkenende, Adv. Mater., 2001, 13,1085.. C. Sanchez, G. Soler-Illia,F. Ribot, T. Lalot, C. Mayer, V. Cabuil, Chem. Mater., October 2001, 13, 10. G. Soler-Illia, C. Sanchez, B.Lebeau, J. Patarin, Chem. Rev., Nov 2002. E. Crepaldi,G. Soler-Illia, D. Grosso, D. Durand and C. Sanchez, Chem. Comm, 2002, 2298. D. Grosso, E. Crepaldi,G. Soler-Illia, B. Charleux and C. Sanchez, Adv. Funct. mater, 2003,13,37. E. Crepaldi,G. Soler-Illia, D. Grosso, A. Bouchara and C. Sanchez, Angew. Chemie, 2003, 42,347. E. Crepaldi,G. Soler-Illia, D. Grosso,and C. Sanchez, NJC, 2003,27, 9 - 13 and 2003, 27, 166 - 17. A. Bouchara ,G. Soler-Illia, JY Chane-Ching and C. Sanchez, Chem. Comm, 2002, 1234. C.Sanchez, G. Soler-Illia, F. Ribot, D. Grosso Comptes-Rendus Acad Science Chimie, 2003, 8, 109. E. Crepaldi,G. Soler-Illia, D. Grosso, F. Ribot, F. Cagnol and C. Sanchez, JACS, 2003. D. Grosso et al ; Nature Materials 2004 and Chem mater 2004, Advanced Functional Materials 2004. L. Nicole et al, Chem. Comm 2004; F. Goetman et al Chem. Comm 2004

E-IV.02 14:30 -Invited- MESOSTRUCTURED PIGMENTS IN VARIOUS COATINGS Peter Alberius(a), Nina Andersson(a), Pär Wedin(a), Lennart Bergström(b), Andrew

Fogden(a), (a)YKI Institute for Surface Chemistry, Stockholm, Sweden, (b)Inorganic Chemistry, Stockholm University, Stockholm, Sweden

There are many different potential applications of films containing well defined mesostructured materials (porous or hybrids) ranging from dye-based optically active films, membranes, catalytically active substrates, controlled delivery of actives in coatings or topological formulations to the inkjet paper coatings. Manufacturing continuous mesostructured hybrid films over big areas is possible but increasingly difficult when thicker films (above a few microns) are needed or when mesoporous films are required. An industrially viable route for overcoming these difficulties would be to disperse mesostructured powdered materials in a suitable polymeric binder that is subsequently applied to the various substrates. One example of this approach will be given for aerosol generated mesoporous silica materials coated on inkjet printing papers demostrating superior print quality as compared to conventional inkjet paper coatings. Another example include the formulation of an aqueous based acrylic latex paint containing aerosol generated mesostructured hybrid materials with photochromic properties. The given examples will indicate a viable route for scaling up the use of well defined mesostructured materials with tailor made properties using conventional coatings technologies.

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E-IV.03 15:00 “DEFECT-FREE” SELF-ASSEMBLED HYBRID FILMS WITH A TETRAGONAL MESOSTRUCTURE

Plinio Innocenzi(a), Luca Malfatti(a), Tongjit Kidchob(a), Paolo Falcaro(b), Stefano Costacurta(b), Giovanni Mattei(c), Heinz Amenitsch(d), Augusto Marcelli(e), Mariangela Cestelli Guidi(e), Massimo Piccinini(e), Alessandro Nucara(f), (a)Laboratorio di Scienza dei Materiali e Nanotecnologie, Nanoworld Institute, Dipartimento di Architettura e Pianificazione, Università di Sassari,Palazzo Pou Salid, Piazza Duomo 6, 07041 Alghero (Sassari), Italy, (b)Dipartimento di Ingegneria Meccanica, Settore Materiali, Università di Padova, Via Marzolo 9, 35131 Padova, Italy, (c)Dipartimento di Fisica “Galileo Galilei”, Università di Padova, via Marzolo 8, 35131 Padova, Italy, (d)Institute of Biophysics and X-ray Structure Research, Austrian Academy of Sciences, Schmiedelstraße 6, 8042 Graz, Austria, (e)Laboratori Nazionali di Frascati - INFN, Via E. Fermi 40, 00044 Frascati, Italy, (f)Dipartimento di Fisica, Università di Roma “La Sapienza”, P.le A. Moro 2, 00185 Roma, Italy

Hybrid mesostructured materials are promising candidates to be used in nanotechnologies as the introduction of functional organic groups adds the required properties to the material. We present the synthesis of one-pot self-assembled hybrid films, deposited via dip-coating and synthesized by the co-hydrolysis of methyltriethoxysilane and tetraethoxysilane. The films show a high "defect-free" mesophase organization that extends throughout the films thickness and for domains of a micron scale, as shown by scanning transmission electron microscopy. We have defined these films "defect-free" to describe the high degree of order achieved without defects in the pores organization, such as dislocations of pores or stacking faults. A novel mesophase, which is tetragonal I4/mmm (in the space group), is observed in the films. This phase evolves but retains the same symmetry throughout a wide range of temperature of calcination.

The thermal stability and the structural changes as a function of the calcination temperature have been studied by small angle X-ray scattering, scanning transmission electron microscopy and Fourier transform infra-red spectroscopy. We have employed a combined approach using transmission electron microscopy, small angle X-ray scattering and computer simulation to achieve a clear identification of the organized phases. In situ Fourier transform infrared spectroscopy employing synchrotron radiation has been used to study the kinetics of film formation during the deposition. The experiments have shown that the polycondensation reactions are three times slower in presence of surfactant during self-assembly. The slower kinetics of silica species can explain the high degree of organization that can be reached in EISA synthesis of films in MTES-TEOS systems.

E-IV.04 15:15 MICROPOROUS FILMS CONTAINING TITANIA NANO-PARTICLES DERIVED

FROM THE THERMAL DECOMPOSITION OF THE TITANIA/PDMS HYBRID M. Nakade, KOSÉ Corp., Azusawa 1-18-4, Itabashi-ku, 174-0051 Tokyo, Japan, K.

Ichihashi and M. Ogawa, Waseda Univ., Nishi-waseda 1-6-1, Shinjuku-ku, 169-8050 Tokyo, Japan

Microporous films containing titania nano-particles were obtained by thermal decomposition of the titania/poly(dimethylsiloxane) (PDMS) hybrid films derived from co-hydrolysis and co-condensation of titanium tetraisopropoxide and methoxy-functionalized PDMS. As-synthesized hybrid films prepared by depositing the sol on poly(ethylene) film were transparent and flexible, and had high homogeneity. Ti atoms form amorphous titania domains of nano meter sizes. The organic groups of PDMS were decomposed at 400 degrees C in air to form porous films. Though the calcined films were rather brittle compared to the as-synthesized films, they are still transparent and homogeneous. The BET surface area of the films after the heat treatment at 400 degrees C for 5 hr were over 400 square meters per gram, while that of the as-synthesized hybrid films were of the order of several square meters per gram. According to the BDDT classification, the isotherms of the calcined films were Type I, showing the films were microporous. The thermal decomposition of the organic groups was accompanied with the transformation of the silicone to silica. On the other hand, the titania domains were still amorphous after the heat treatment at 400 degrees C.

E-IV.05 15:30 RUTHENIUM(II) COMPLEXES AND POLYMERS WITH POTENTIAL

APPLICATIONS IN MESOSTRUCTURED THIN FILM SOLAR CELL DEVICES Veronica Marin, Elisabeth Holder and Ulrich S. Schubert, Laboratory of Macromolecular

Chemistry and Nanoscience, Eindhoven University of Technology (TU/e), P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands

People are searching for reliable, cheap and environmentally friendly energy resources. The sun matches all these requirements: it is reliable, omnipresent and for free. A very appealing approach to use this source is the bulk heterojunction architecture (p-n type), in which an electron-donating organic material (p-type, called donor) and an electron-acceptor organic material (n-type, called acceptor) are randomly mixed to create a composite material that exhibits phase separation on a nanoscale level.

The introduced approach involves ruthenium polypyridyl complexes, which can successfully act as p-type material since they possess suitable optical, magnetic and electrochemical properties. To prevent formation of aggregates, which often leads to self-quenching and to reduced lifetimes of the devices, covalent bonding of the metal complex to different polymer backbones might be helpful. Some recent novel synthetic concepts will be introduced and preliminary processing results will be given. Moreover preliminary studies on the quenching behavior (in solution and in thin films) of the ruthenium species by PC60BM showed encouraging results for a donor-acceptor pair in a bulk-heterojunction cell.

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E-IV.06 15:45 EXCESS NOISE IN A POLY(VINYL BUTYRAL)\CARBON BLACK NANOCOMPOSITE GAS SENSITIVE RESISTOR

K.I. Arshak, L.M. Cavanagh, E.G. Moore, Electronics and Computer Engineering Department, College of Informatics & Electronics, University of Limerick, Plassey Technological Park, Limerick Ireland

Currently there is considerable interest in conducting polymer composites functioning as gas sensitive resistors. These composite gas sensors can operate at room temperature, which is a distinct advantage over the semiconducting oxide based devices. Also, the study of noise in the physical properties of condensed matter have led to important insights into the physical phenomena that are associated with fluctuations. The most pronounced activity in this field is definitely the ever-present excess noise. Presented are the results of excess noise measurements on poly(vinyl butyral)\carbon black nanocomposite gas sensitive resistors. The polymer\carbon black composite device was prepared by dissolving 120mg of poly(vinyl butyral) in 20ml of THF. 80mg of carbon black was shear mixed into the polymer solution and a microlitre syringe was used to deposit a drop of the suspension onto thin-film parallel electrodes, which were thermally evaporated onto an alumina substrate. A noise index (NI) of up to 7dB was measured for these samples. As well as having practical significance, due to the NI being an important parameter for any resistor, investigations of excess noise yields additional knowledge about the nature of electronic conduction that takes place in the composites from which the resistors are made. Noise power spectra of the devices under bias currents from 80uA to 150uA were obtained. The measurements allowed the lower-detection-limit of the devices to various organic solvent vapours and under various bias currents to be determined. Details on the design and calibration of a novel noise measurement system based on instrumentation amplifiers are also presented.

16:00 BREAK

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Session chairs : Clément Sanchez and Shinji Inagaki E-IV.07 16:30 -Invited- POLYMER AND BIOPOLYMER CLAY NANOCOMPOSITES FOR

ELECTROCHEMICAL AND ELECTROANALYTICAL APPLICATIONS P. Aranda, M. Darder and E. Ruiz-Hitzky, Instituto de Ciencia de Materiales de Madrid,

CSIC, 28049 Madrid, Spain The study of nanocomposites based on polymer-clay systems is a topic of considerable

interest in the search of new structural and functional materials with advantages over conventionally reinforced polymers. One of the advantages of these systems is the possibility to be processed as thin films which is of crucial interest in the development of active components of certain devices. In this communication it will be introduced a general overview about polymer- and biopolymer-clay nanocomposites showing attractive properties for electrochemical and electroanalytical applications including the last advances achieved on this field by our research group.

Among the functional nanocomposites, PEO-smectites is possibly the most studied system because of its interest as solid electrolyte for rechargeable Li-batteries. Other group of nanocomposites is that involving conducting polymers, e.g. polyaniline and polypyrrole, as well as precursors of conducting materials, e.g. polyacrylonitrile, that can be used as active phases of electrodes for different electrochemical devices. Finally, a new class of nanostructured materials is that based on the combination of clays and biopolymers. Among other applications these bionanocomposites can be used as active phase of electrochemical sensors. For instance, the controlled intercalation of chitosan in montmorillonite transforms the clay in an anion exchanger that can be processed as active phase of sensors for the detection of anionic species.

E-IV.08 17:00 HYBRID CONDUCTING POLYMER-LAYERED CHALCOGENIDE

NANOCOMPOSITES P.G. Hill, P.J.S. Foot, R. Davis, Materials Research Group, School of CPS, Kingston

University, Penrhyn Road, Kingston, Surrey KT1 2EE, U.K. Inorganic/conducting polymer nanocomposites with alternating layers of inorganic host and

organic polymer, have been made by intercalation of aromatic monomers into lamellar metal thiophosphates or MoO3 followed by mild oxidation. The materials were studied by powder x-ray diffraction, thermogravimetry and infrared spectroscopy, and the organic monomers were templated by the layered host compounds. Increased conductivity of the hosts was observed after intercalation, and it was further enhanced after oxidation. Transport was largely ionic in the monomer intercalates, but it became fully electronic after polymerisation.

The powdered nanocomposites could readily be dispersed in polar solvents and deposited as adherent layers onto alumina, glass or metal substrates.

E-IV.09 17:15 SYNTHESIS AND CHARACTERIZATION OF SUPERPARAMAGNETIC

NANOCOMPOSITES BY GRAFTING BIOCOMPATIBLE POLYMERS ONTO MAGHEMITE NANOPARTICLES

C. Flesch(a), C. Delaite(a), E. Bourgeat-Lami(b), E. Duguet(c), P. Dumas(a), (a)Laboratoire de Chimie Macromoléculaire – ENSCMu-CNRS (ICSI-UPR 9069), 3 rue A. Werner, 68093 Mulhouse cedex, France, (b)Laboratoire de Chimie et Procédés de Polymérisation – CNRS-CPE (LCPP-UMR 140) – Bât. 308F, 43, bd du 11 novembre 1918, 69616 Villeurbanne cedex, France, (c)Institut de Chimie de la Matière Condensée de Bordeaux – CNRS-UB1 (ICMCB-UPR 9048), Université Bordeaux-1, 87 avenue du Dr A. Schweitzer, 33608 Pessac, France

Hybrid organic-inorganic nanomaterials based on a magnetic core and a polymeric shell offer promising opportunities for therapeutic applications including MRI contrast agents, drug carriers and hyperthermia mediators. We focused on maghemite and poly(e-caprolactone) to prepare materials combining the superparamagnetism and the inocuity of iron oxide nanoparticles with the polyester biocompatibility. Two grafting procedures have been developed. The first one consists in the immobilization of an amino-silane coupling agent at the surface of the maghemite, which will act as a co-initiator in the aluminum isopropoxide catalyzed ring opening polymerization of e-caprolactone "from" the inorganic surface. The amount of grafted polymer was shown to depend on the monomer concentration and on the amine to aluminum ratio. Further experiments with poly(ethylene oxide) were also achieved, producing a water stable dispersion. An alternative technique consisted in a coupling reaction between silane-functionalized poly(e-caprolactone) chains and the surface hydroxyls of maghemite providing well defined nanocomposites.

E-IV.10 17:30 STABLE BLUE-EMITTING CONJUGATED POLYMER/INORGANIC LAYERED

COMPOUND GUEST/HOST NANOCOMPOSITES Asaf Albo, Eyal Aharon, Michael Kalina and Gitti L. Frey, Department of Materials

Engineering, Technion – Israel Institute of Technology, Haifa 32000, Israel Polyfluorenes are promising polymers for blue polymer light-emitting diodes due to their

high photoluminescent efficiency, thermal stability and liquid crystalline properties. However, in addition to the blue emission, many groups report on a broad green emission band which is enhanced while driving current through the device. This undesirable emission is associated with oxidation-induced fluorenone defects. Whether the green emission is from a localized excited state, or from an excimer state involving closely stacked polymer chains, is an on-going debate which has direct consequences on the fabrication of long-lived blue PLEDs. In this study a blue-emitting conjugated polymer, poly(9,9-dioctylfluorene), is confined into the interlayer space of an inorganic layered metal dichalcogenide material. The composite is prepared through Li intercalation, exfoliation, and re-stack in the presence of the polymer. Oriented thin films of the composite are grown at the organic/aqueous interface and transferred to a variety of substrates. The morphology of the inorganic interlayer-space

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enforces a planar arrangement on the polymer while preventing the p-p stacking, as evident from XRD and optical absorption measurements. The decoupling of the extended planar intrachain conformation form the p-p interchain interactions provides a unique opportunity to study the optical properties of a conjugated segment while inhibiting aggregates and excimer formation. Photoluminescence measurements of annealed films show that the blue-emission degradation and increase of green-emission observed in pristine polymer films is suppressed by incorporating the polymer into the inorganic matrix. Furthermore, the blue emission of the nanocomposites is preserved after over two years at ambient conditions, while the photoluminescence spectrum of polymer films stored under the same conditions for the same period of time show only the broad green peak. These results indicate that fluorenone defects are insufficient to generate the green emission and that aggregation is also required, emphasizing the necessity to control interchain interactions to improve device performance.

17:45-20:00 POSTER SESSION I 19:00 AWARD CEREMONY The symposium organizers and the candidates to the graduate student

award are requested to attend. CONFERENCE RECEPTION

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POSTER SESSION I Wednesday, June 1, 2005

17:45 – 20:00

Session chairs : Makoto Ogawa and Michaela Klotz E/PI.01 ELECTROFORMING PROCESSES FOR PLATINUM NANOISLAND THIN FILMS C. Bertoni, D.E. Gallardo, S. Dunn, Nanotechnology Group, School of Industrial and Manufacturing Science,

Cranfield University, Cranfield, Bedfordshire MK43 0AL, U.K. This work details an investigation of the electroforming processes for platinum discontinuous thin films. Pt was

deposited on glass by sputtering at room temperature. Optimal conditions to get isolated nanoislands (average gap approx. 3nm) were identified by using the influence of deposition rate changes on Pt nucleation. Self-assembled metal nanoisland films were electrically characterised in vacuum and air. Current-voltage characteristics typically showed voltage-controlled negative resistance (VCNR) like behaviour and the current maximum shifted with the electrode separation. Electroforming operated under high current density regimes was non-regenerative as samples showed irreversible changes in resistance during subsequent voltage sweeps. The SEM examination of the film revealed a change in the microstructure of the metal percolated layer. Such modifications arise as a result of the current flowing through the film which induces electro and thermal migration processes. Current-induced effects were studied by modelling the MN layer as an array of cubic cells forming a resistive network. Plots of the current distribution showed that hot-spots develop along conductive paths. At these points, electromigration combined with the development of resistive heating can lead to the progressive destruction of current channel segments. Hence, current profiles and SEM micrographs were interpreted as experimental evidences of a "macroscopic" electrical breakdown of the sample conduction due to microstructural modifications of the metal thin film. The reduction of the number of spanning clusters responsible for the ohmic component and the consequent resistive heating along the current channels, prevented the metal migration and stable current profiles were obtained.

E/PI.02 SPECTROSCOPIC INVESTIGATION ON THE IN SITU POLYMERIZATION OF SELF ASSEMBLED

MONOLAYERS OF CARBAZOLYLDIACETYLENE CDS9 ON SILVER-COATED GLASS E. Giorgetti(a), M. Muniz-Miranda(b), G. Dellepiane(c), G. Margheri(d), S. Sottini(a), M. Alloisio(c), C.

Cuniberti(c) (a)INSTM and Istituto dei Sistemi Complessi - CNR, Via Panciatichi 64, 50127 Firenze, Italy; (b)Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy; (c)INSTM and Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, I-16146 Genova, Italy; (d)Istituto dei Sistemi Complessi - CNR, Via Panciatichi 64, 50127 Firenze, Italy

The possibility of growing self-assembled monolayers (SAMs), through the chemical adsorption of thiols-or disulfides- containing molecules on suitably prepared metal surfaces, is achieving increasing importance. In particular, the use of diacetylenic monomers having these reactive groups provides the possibility to yield, after topochemical polymerisation, robust monolayers exhibiting the typical properties of the conjugated skeleton. This unique combination of robustness and optoelectronic properties makes these systems important either for fundamental studies and for practical applications, such as high resolution lithography or sensing. In this paper, we describe a spectroscopic study of SAMs of a novel carbazolyldiacetylene, the CDS9, deposited on Ag-coated glass substrates. The choice of this compound has been dictated by our long-time experience in the synthesis, in the spectroscopic characterization and in the linear and non linear study of solutions and thin films of carbazole-containing polydiacetylenes. In particular, we will demonstrate the topochemical UV polymerisation of CDS9 monolayers, by monitoring both the absorption coefficient (with Surface Plasmon Spectroscopy) and the Raman response of the organic film, during UV exposure. The roughness features of the organic/metal interfaces of our samples were varied, in order to enhance the Raman response of the ultra thin molecular layer either by SERS or by Resonant Raman effect. This goal was achieved by suitably choosing the duration and rate of the Ag evaporation. The paper presents a comparison among results obtained with different Ag/CDS9 interfaces and with CDS9 powders.

E/PI.03 SUBSTRATES DO INFLUENCE THE ORDERING OF MESOPOROUS THIN FILMS A Chougnet, C. Heitz, E. Søndergard, M. Klotz, Surface du Verre et Interfaces, Unité Mixte de Recherche

CNRS/Saint-Gobain, UMR 125, 39 Quai Lucien Lefranc, 93303 Aubervilliers cedex, France, J.-M. Berquier, Saint-Gobain Recherche, 39 Quai Lucien Lefranc, 93303 Aubervilliers cedex, France,, P.-A. Albouy, Laboratoire de Physique des Solides UMR 8502, Université de Paris Sud, 91405 Orsay, France

Films of ordered mesostructured silica may be used in a large variety of applications such as for example microelectronics, filtration and sensors. Thus, the substrate can be of different nature, and often very different from glass, on which most of the characterization studies are performed. The influence of the substrate on the ordering of mesoporous silica films then needs to be considered. Two kind of ordered structures, a cylindrical hexagonal and a compact hexagonal arrangement of micelles were synthesized using either CTAB or a pluronic block copolymer as templating agents. The ordering of thin films deposited on glass, dielectrics (Si3N4, SiTiOx) and a metal (Ti) were compared. We observed that the ordered texture of the films was greatly influenced by the substrate. In order to separate between the effects of surface rugosity and surface forces, glass substrates were systematically modified by grafting of statistical ethylene oxide/propylene oxide (EO/PO) copolymers. Varying of the EO content allowed a fine tuning of the hydrophilicity of the surface. In this case, the same quality of ordering as on glass is observed but a higher contraction of the ordered structure is systematically observed. This is ascribed to the close chemical nature between the grafted substrate and the templating molecules, which fasten the formation of the ordered structure.

E/PI.04 PREPARATION OF MESOPOROUS SILICA COATING FILMS BY THE STöBER METHOD COMBINED

WITH SUPRAMOLECULAR TEMPLATING APPROACH Naoki Shimura(a), Makoto Ogawa(a,b), (a)Graduate School of Science and Engineering, Waseda University,

Nishiwaseda 1-6-1, Shinjuku-ku, Tokyo 169-8050, Japan, (b)Department of Earth Sciences, Waseda University, Nishiwaseda 1-6-1, Shinjuku-ku, Tokyo 169-8050, Japan

Mesoporous silica films are potential materials for the uses as optoelectronics and separation applications. Controlled nanostructures and morphology (thickness and homogeneity) of films should be achieved to the optimum performances, so that the preparation of mesoporous silica films by various synthetic approaches has been conducted. Here, we report the deposition of transparent silica-cetyltrimethylammonium cation coating films on borosilicate glass substrates by the Stöber method, which was developed for the preparation of silica sphere

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with controlled particle size, combined with supramolecular templating approach. As an example, the silica-cethyltrimethylammonium cation coating film with the thickness of ca. 100 nm was deposited on the substrate (30 x 30 x 0.2 mm) from homogeneous solution (125 ml) of tetraethoxysilane, cethyltrimethylammonium chloride, water, methanol, and ammonia (the molar ratio of these was 1 : 0.4 : 774 : 1501 : 72) at room temperature. The calcination of the film at 623 K in air led the mesoporous silica film with the pore diameter and the BET surface area of 2.4 nm and ca. 1000 m2 g-1, respectively. The present synthetic method is applicable to coat various substrates including finite particles with mesoporous silica layers.

E/PI.05 THE FCC STRUCTURE IN MESOPOROUS THIN FILMS Michaela Klotz, Unité Mixte St Gobain/CNRS, UMR 125, 39 quai Lucien Lefranc, 93303 Aubervilliers, France,

F. Bosc and A. Ayral, Institut Européen des Membranes, UMR 5635, CNRS-ENSCM-UMII, CC047,Université Montpellier II, 34095 Montpellier Cedex 5, France, P.-A. Albouy, Laboratoire de Physique des Solides UMR 8502, Université de Paris Sud, 91405 Orsay, France

Mesoporous thin films built by spin- or dip-coating are konwn to experience a normal-to-the-plane contraction during solvant evaporation and this phenomenon generally leads to a change in lattice symmetry. We present here silica and titania-based thin films that exhibit an unusual face centred cubic structure after deposition. The ordered domains are preferentially oriented with the denser (111) planes of the initial cubic structure parallel to the surface. The solvent-induced contraction occurs in the [111] direction and leads to a rhomboedral structure. Mainly based on small-angle X-ray diffraction, this work describes the observed evolution in crystallographic terms.

E/PI.06 PREPARATION OF ULTRA THIN FILMS OF DNA BASES WITH LASER LIGHT AT 157 NM A.C. Cefalas, E. Sarantopoulou, Z. Kollia National Hellenic Research Foundation, TPCI, Athens, Greece, Z.

Samardlija, S. Kobe, Jozef Stefan Institute, Department of Nanostructured Materials, Ljubljana, Slovenia By applying laser ablation at 157 nm, ultra-thin films of the DNA bases adenine, guanine, cytosine were fabricated

by etching of bulk crystals deposited on Si substrates. The film thickness is reduced down to few nanometres. This was possible because only photochemical dissociation of DNA bases was taking place following illumination with laser light at 157 nm and ablative photofragments were removed from the interaction area with supersonic speed [1]. For a laser fluence of 1 mJ/cm2 per laser pulse, 0.5 nm of film thickness was removed on the average, making possible precise sub-nanometer control over the film thickness. High resolution AFM images reveal the same morphology between exposed and non exposed to light areas, suggesting limited chemical changes on the surface of the remaining substrate.

References 1. Photodissociation dynamics of DNA bases. E. Sarantopoulou, Z. Kollia, A. C. Cefalas, S. Kobe and Z. Samardžija. Journ. Biolog. Physics V29, 149-158, (2003).

E/PI.07 SOL-GEL FORMED VANADIUM DIOXIDE ON POROUS ALUMINA Alexander Khodin(a,b), Hwack-In Hwang(a), Elena Outkina(a,c), Song-Min Hong(a), Alla Vorobiova(c),

(a)Korean Electronics Technology Institute, Korea, (b)Institute of Electronics, National Academy of Sciences of Belarus, Belarus, (c)Belarussian State University of Informatics and Radioelectronics, Belarus

Sol-gel deposition technique is developed to obtain vanadium dioxide film on nano-ordered substrates of porous anodic oxide of aluminium. The substrates were prepared by electrochemical anodizing of sputtered aluminium film in oxalic acid electrolyte. Pores size was ~80 nm.

Vanadium oxytriisopropoxide was used as a precursor for sol-gel processing. The precursor was added into isopropanol, and then was catalyzed with acetic acid, with subsequent stirring at room temperature. After stirring, the solution was diluted with additional isopropanol with subsequent stirring for 120 min. The coatings were deposited onto substrates in air. The solution was deposited onto the substrates at 25°C by spin coating. Deposited coatings were dried at 80°C for 20 min in air. Then, the wafers were annealed in air in a furnace at 300°C for 60 to 90 min. The formed films were enough stable to convert to VO2 phase by annealing. It was performed in a tube furnace with gas flow at 500°C for 120 min. The gas mixture tested were Ar+5%H2 and pure Ar. Better results were obtained under anneal in pure Ar. In this case, room temperature resistance of the films was 0.4 to 6.8 MΩ. The films had pronounced temperature dependence of resistance, characteristic for vanadium dioxide. As evidenced by x-ray diffraction analysis, the films contained strongly pronounced VO2 crystalline phase. Thus, porous alumina substrate facilitates single-phase vanadium dioxide formation by sol-gel technique. Ordered layers of VO2 possess of specific "soft" switching characteristics under external electric field supply, which is caused by semiconductor-to-metal phase transition in the vanadia nanorods filling the alumina pores.

E/PI.08 ORDERED MAGNETIC NANOWIRES BASED ON MESOPOROUS SILICA THIN FILMS – SYNTHESIS

AND CHARACTERISATION K.S. Napolskii, A.A. Eliseev, A.V. Lukashin, Dept. of Materials Science, Moscow State University, Moscow

119992, Russia. E.A. Kelberg, S.V. Grigoriev, A.I. Okorokov, Petersburg Nuclear Physics Institute, Gatchina, St.Petersburg 188300, Russia, H. Eckerlebe, GKSS Forschungszentrum, 21502 Geesthacht, Germany, N.A. Grigorieva, St-Petersburg State University, St-Petersburg 198504, Russia, W.H. Kraan, Interfacultair Reactor Instituut, TU-Delft, 2629 JB Delft, The Netherlands

Synthesis and characterization of one-dimensional magnetic nanoparticles (nanowires) in the mesoporous silica films is emerging as a new area of great technological and scientific interest, in particular, it is a key technology for developing novel high-density data storage devices. Recently, the formation of epitaxial mesoporous silica films with highly ordered system of mesochannels was reported on silicon (110) substrate. In the case of encapsulation of a magnetic material (for example, iron) into the pores, one can get a perfect system of isolated nanomagnets inside the diamagnetic matrix, which could find application as high-density data storage devices. Our recent investigations show, that mesoporous silica is the perfect nanoreactor for synthesis of highly anisotropic magnetic nanoparticles (nanowires). The synthetic method based on incorporation of hydrophobic metal compounds (e.g., Fe(CO)5) into the hydrophobic part of the as-prepared SiO2/surfactant composite and subsequent temperature treatment for decomposition of the complex. The suggested method results in the formation of iron nanowires inside the silica framework. Particles are uniform and well ordered in the silica matrix. In the present work, a novel method for the preparation of iron nanowires in mesoporous silica thin films on Si substrate is discussed. Film nanocomposites were characterized by TEM, ED, SAXS, SANS, and magnetic measurements. It was shown that the suggested method results in the formation of functional materials with nanosized magnetic elements in amorphous silica matrix. This work is supported by RFBR (03-03-32182 and 04-02-17509) and INTAS (2001-204 and 03-55-1523).

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E/PI.09 FABRICATION OF THIN FILMS OF NANOSTRUCTURED MATERIALS USING ELECRODES MODIFIED BY MESOPOROUS SILICA THIN FILMS

U-Hwang Lee and Young-Uk Kwon We have developed a simple and facile synthesis method of various mesostructured silica thin films with pore

sizes in the range of 3 to 7 nm on various substrates including glass, ITO and Si wafers. The open pores from the film surfaces of the cubic and worm-like mesoporous thin films make it possible to grow a variety of nanostructured materials inside the pores by electrochemical means after forming the mesoporous silica films on conductive substrates. In this way, we have grown thin films of nanostructured Pt and Ag whose structures can be controlled by varying the electrodeposition conditions as well as using the right structure of the templates. Arrays of vertically aligned nanorods and nanomeshes by interconnecting the nanorods were formed. The cyclicvoltametric data of the Pt nanomesh show enhanced current density compared with flat Pt thin films.

E/PI.10 OPTICAL PROPERTIES OF ZNO NANOPARTICLES STABILIZED IN LAYER SILICATE DISPERSIONS

AND ULTRATHIN FILMS Krisztina Szendrei, Tamás Szabó, József Németh, László Korösi and Imre Dékány, Department of Colloid

Chemistry and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged Aradi vt. 1, 6720 Szeged, Hungary

Nanocrystals of transitional metals, metal oxides and sulfides have unique physicochemical properties because of their size quantization effect and high surface free energy. Current research on these materials is motivated by precious technological applications like fabrication of nanostructured devices, solar energy conversion, optical coating, sensing of gases and so on.

Our experiments aimed at the preparation of nanometric ZnO particles in layer silicate (montmorillonite and hectorite) suspensions of dimethyl sulfoxide (DMSO) media. ZnO crystals stabilized by zinc bis(cyclohecane-butyrate) in DMSO showed strong fluorescence, while their heterocoagulation with clay suspensions resulted in the extinction of emission. Aqueous dispersion of zinc hydroxide colloids was synthesized next which, along with hectorite suspensions, was deposited on glass substrates by the layer-by-layer self-assembly (LBL SA) method. ZnO/hectorite films were obtained by heat treatment. Band gap energy of this quasi two-dimensional composite film could be tuned by the layer numbers and deposition times of the nanofilms. Estimation was made for the thickness of multilayers by ellipsometry, while XRD provided structural parameters (basal distances) for the composite. Reflection spectra of the films, irradiated by xenon lamp, were found to be angle-dependent, which was explained by the amplifying and attenuating interference of the optical waves partially reflecting from the interface of alternating multilayers possessing different index of refraction. It was proven, therefore, that the as-prepared ultrathin films can be applied as optical filters and sensors.

E/PI.11 COLLOID SYNTHESIS AND PHOTOCONDUCTIVITY OF CdS, V2O5 AND WO3 DOPED TITANATE

FILMS Szilvia Papp, László Korösi and Imre Dékány Nanostructured Materials Research Group of the Hungarian

Academy of Sciences and Department of Colloid Chemistry, University of Szeged, H, Aradi v. t. 1., 6720 Szeged, Hungary

Semiconductor nanoparticles (CdS, V2O5 and WO3) were incorporated into the hydrogen trititanate layers to examine their influence on the photovoltaic properties of pure titanate powder. Na2Ti3O7 with layered structure was prepared from a 1:3 molar mixture of powdered Na2CO3 and TiO2 by heating at 800 oC for 2 hours, after that the Na+ ions were exchanged for H+ ions by hydrochloric acid treatment. H2Ti3O7 samples dispersed in liquids of various compositions and polarities were used for the preparation of self-assembled titanate/polymer films for further sensor applications. Self-assembled nanofilms were built up from colloidal suspension of negatively charge semiconductor nanoparticles and positively charged PDDA solution by layer-by-layer method. CdS, V2O5 and WO3 nanoparticles were incorporated into the titanate layers. CdS nanoparticles were generated from their precursors in the interlayer space. V2O5, WO3 nanoparticles were prepared by sol-gel method from V2O5crystallite and metalic tungsten in a solution of hydrogen peroxide. Before the intercalation of semiconductor nanoparticles into the layes, those were pre-expanded by incorporation of n-butilammonium ions.

Titanates, their composites and the self-assembled hybrid structures (titanate/polymer/semiconductor) were characterized by X-ray diffraction, optical, electron and atomic force microscopic measurements.

E/PI.12 PHOTOCATALYTIC TiO2 AND TiO2-SiO2 PILLARED CLAY Jae-Hun Yang(a,b), Man Park(b) and Jin-Ho Choy(a), (a)Intelligent Nanohybrid Materials Laboratory, Division of

Nanoscience & Department of Chemistry, Ewha Womans University, Seoul 120-750, Korea, (b)School of Chemistry and Molecular Engineering, Seoul National University, Seoul 151-747, Korea

Highly porous photocatalysts have been prepared by pillaring TiO2 and TiO2-SiO2 nanosol particles into the silicate layers of fluorine mica(Na0.7Mg2.65Si4O10F2). According to X-ray diffraction analysis, the silicate layers are expanded up to 16Å upon intercalation of TiO2 nanosol, whereas 30Å for the SiO2-TiO2 ones, with the formation of micropores in the interstices between sol particles and silicate layers of mica. From the nitrogen adsorption-desorption isotherms, the BET specific surface areas for the TiO2 pillared mica and SiO2-TiO2 one calcined at 400℃ are estimated to be ~ 240 m2/g and ~ 400 m2/g, respectively, and the pore sizes are determined as ca. 14 Å for both samples. In the UV absorption spectra, a pronounced spectral blue shifts are observed due to the quantum size effect of TiO2 nano-particles stabilized inbetween the silicate layers. The photocatalytic activity of the microporous pillared micas has also been studied in terms of photocatalytic degradation of organic dye molecules, such as methylorange and methylene blue, under UV irradiation

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E/PI.13 SELF-ASSEMBLED LAYERED DOUBLE HYDROXIDE/POLYMER COMPOSITES AND POLYMER NANOFILMS: THE EFFECT OF SALT CONCENTRATION ON THE FILM THICKNESS

Judit Ménesi, Viktória Hornok, András Erdohelyi, Imre Dékány Nanofilms of various polymers like polystyrenesulfonate (PSS), polyacrylic acid (PAA), polyethylenimine (PEI),

polyallylamin hydrochloride (PAH) and polydiallyl-dilmethylammoniumchloride (PDDA) were prepared by applying the layer-by-layer self-assembled technique. The polymer solutions were characterized by viscosimetric and streaming potential measurements depending on the pH and the salt concentration. Films from these polymers were built up and the effect of electrolyte concentration on the film thickness was examined by spectrophotometry. The experiments revealed that the applied highest NaCl concentration resulted the thickest films. PSS proved to be the most effective due to its highest specific charge according to streaming potential titrations. Hybride nanofilms were prepared with layered structure materials like Mg-Al 2:1 layered double hydroxide (LDH) and PSS and LDH/hectorite. Nanofilm properties were followed by UV-Vis spectrophotometry, X-ray diffraction (XRD) and atomic force microscopy (AFM). Concentration of PSS even important in film degree of order on the basis of film morphology observations by AFM. These LDH/PSS multilayers on porous ceramic tube support were tested as gas separation membranes successfully and the results were promising. We could prepare multilayers with two positively charged materials like TiO2 and LDH with negatively charged PSS because this structure is stabilized through electrostatic attraction. This composite could be a potential two-dimensional photocatalyst for self-cleaning surfaces.

E/PI.14 VACUUM SEEDING AND SECONDARY GROWTH ROUTE TO SODALITE MEMBRANE Sung-Reol Lee(a), Anne Julbe(b), Jin-Ho Choy(a), (a)Division of Nano Science & Department of Chemistry,

Ewha Womans University, Seoul 120-750, Korea, (a)Institut Européen des Membranes(UMR 5635 CNRS), UMII, CC 047, place Eugène Bataillon, 34059 Montpellier Cedex 5, France

Sodalite membrane has been successfully fabricated on tubular porous -Al2O3 supports by secondary growth method with vacuum seeding. In the seeding process, the colloidal seeding particles were agglutinated not only onto the surface of alumina support but also within the pores by vacuum sucking method. The colloidal sodalite solution was prepared by suspending nanocrystalline sodalite particles of ~ 30 nm, which was synthesized in advance by the solid-solid transformation reaction from the Al2O3 pillared clay, and finally by ultrasonicating the suspension for 30 min. To obtain efect-free sodalite membrane, the sodalite crystals were grown directly on the alumina support in a mixture solution containing alumina and silica species under the hydrothermal reaction condition. The as-synthesized sodalite membranes were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The thickness and the quality of sodalite membrane could be controlled by the hydrothermal reaction time (12 ~ 24 h) and temperature (100 ~ 150 oC) under the mother solution of 5Na2O:2SiO2:Al2O3:1000H2O.

E/PI.15 MANIPULATION OF BOEHMITE SOLS FOR INK-RECEIVING LAYERS Sung-Reol Lee, Jin-Ho Choy, Division of Nano Science & Department of Chemistry, Ewha Womans University,

Seoul 120-750, Korea Boehmite sols have been prepared by crystallization of amorphous aluminum hydroxide gel obtained via the

hydrolysis of aluminum alkoxides and by subsequent peptization process using acetic acid. The boehmite crystallite size increases from 5 to 25 nm as a function of initial Al concentration in amorphous gel along with the increase in the pore volume (from 0.36 to 0.66 ml/g) and size (from 5 to 25 nm), but with the decrease in the d(020) spacing (from 6.30 to 6.16 Å) and the specific surface area (from 375 to 155 m2/g). Especially, the pore size of boehmite sol particles is similar in the crystallite size along the b axis, indicating that the pore size depends on the fibril thickness along the b axis among the crystallite dimension of boehmites. In addition, the boehmite top layer prepared on the polyester substrate could play a role as excellent ink absorbing and transparent film, which is evidenced by inkjet printing experiments. Therefore, the present manipulation of boehmite sols could not only be applied to exact tailor-made of desired textual properties, but also would be interesting in a viewpoint of industrial application for mesoporous top layers.

E/PI.16 STUDIES ABOUT THE EXFOLIATION OF LAYERED HEXANIOBATE Ana L. Shiguihara, Marcos A. Bizeto and Vera R.L. Constantino, Instituto de Química – Universidade de São

Paulo, Av. Lineu Prestes 748, 05508-900 São Paulo, Brazil We have been exploring the exfoliation process of H2K2Nb6O17 in solutions of n-alkylamines. In this work, it

was investigated the exfoliation of the hexaniobate in tetra-n-butylammonium hydroxide (TBAOH) solution, an efficient media to promote the separation of niobate layers and also the formation of nanoscrolls [1]. A fixed amount of H2K2Nb6O17 was suspended in solution of TBAOH (molar ratios amine/H+-niobate = 0.25, 0.50, 0.75 and 1.0). The deposited solid was separated from the opaque suspension (i.e., the exfoliated solid). The dispersion of exfoliated particles was characterized by electronic spectroscopy while the exfoliated solid, by XRD, surface area measurement, SEM and HRTEM. The deposited solids do not have organic species intercalated and the suspensions containing the ratio TBA+/H+-niobate ≥ 0.5 produce the highest amount of dispersed solid (ca. 65%). The exfoliated solid isolated from suspensions with ratio 0.75 contains 10% of TBA+ neutralizing the layer charge. The sample isolated at pH 1 presents specific area of 139 m2g-1 while K4Nb6O17 possesses only 2 m2g-1. The systems containing plate and tubular particles have potential application in (photo)catalysis and sensors areas.

[1] G.B. Saupe et al., Chem. Mater., 12: 1556, 2000. E/PI.17 NEOFORMED PHASES EXHIBITING MESOSTRUCTURE IN THE FIELD OF NUCLEAR GLASS

ALTERATION. INFLUENCE OF TEMPERATURE ON OBSERVED PHASES P. Frugier(a), T. Chave(a), F. Rieutord(b), a)Commissariat à l’Énergie Atomique – CEA Valrhô

DIEC/SESC/LCLT, BP 17171, 30207 Bagnols-sur-Cèze Cedex, France, (b)Commissariat à l’Énergie Atomique – CEA Grenoble DSM/DRFMC/SI3M/PCM, 38045 Grenoble Cedex 9, France

The long term behaviour of the French R7T7 nuclear glass has been for many years an intensive field of research since it will define the overall resistance of the radionuclide containment matrix. As a matter of fact, recent studies show that the alteration kinetic of glass remains the same or is slightly decreasing with time however it never reaches zero. Thus, even if long term kinetic is about four orders of magnitude lower than the initial alteration rate, in a ten thousand year disposal most of the glass will be altered during this residual state with a 5 nm per year kinetic at 50°C. Two main mechanisms are considered in order to explain such behaviour. The first one is the diffusion of elements through an amorphous altered glass layer. The diffusion will inevitably improve the concentrations and the ionic force of the system and chemical changes will occur with time. Hence, neoformed

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phase precipitation of phyllosilicates or zeolites is considered as a second possible mechanism which can maintain the alteration kinetic or even trigger lixiviation resumption. The resulting phases can be mesostructured smectites with 15 Å interlayer spacing or well crystallized zeolite structure like analcime or pollucite. Nevertheless, these entities are not always observable. We will point out to what extend temperature is a key factor for their crystallisation thanks to SEM, TEM and XRD analysis.

E/PI.18 POLYMER-NANOCLAY HYBRIDS OBRTAINED BY EMULSION POLYMERIZATION OF VINYL

ACETATE IN PRESENCE OF POLYVINYL ALCHOL AND ORGANICALLY MODIFIED MONTMORILLONITE

Dan Donescu(a), Mihai Cosmin Corobea(a), Sever Serban(a), Catalin Ducu(b), Viorel Malinovschi(b), Ioan Stefanescu(b), (a)National R-D Institute for Chemistry and Petrochemistry- ICECHIM Bucharest, Spl.Independentei nr.202, 060021, Romania, (b)University of Pitesti, Research Center for Advanced Materials, Targul din Vale street, no.1, Pitesti, 110040, Romania

A novel polymer-nanoclay hybrid system based on polyvinyl acetate (PVAc)-organically modified montmorillonite (OMMT) has been developed via emulsion polymerization technique. Organically modified silicates are viable systems for dispersion polymerization of common monomers like methyl methacrylate, styrene, etc. By establishing the swollen capacity of montmorillonite Na and an organically modified montmotillonite with VAc, we deduced that compatibility between partners is related by hydrophobic interaction depending on monomer and montmorillonite hydrophobic nature. This interaction is very important for in-situ polymerization point of view. The hybrid materials were synthesized by one-step emulsion polymerization of VAc in presence of organically modified montmorillonite (OMMT) using polyvinyl alcohol (PVA) as stabilizing agent. Using an OMMT weight amount between 2.5-25 % related to monomer load, VAc polymerization occurs with good conversion, over 90 %. Conversions of VAc are not significantly affected by OMMT load in the polymerization system. From kinetic curves, the maximal reaction rates showed a variation between 1.12 - 2 g/min. related to OMMT wt. load. Stable latexes are obtained only with small amounts of OMMT. At higher concentrations of OMMT systems are stable for only few days, generating a phase separation with gel formation. For a better understanding APV-OMMT hybrids were prepared via solution intercalation to be compared with PVAc-OMMT hybrids obtained by emulsion polymerization using PVA. TGA and XRD analyses were performed to observe the structural behavior and electronic microscopy TEM for morphological determination, and structure confirmation.

E/PI.19 STRUCTURE AND ELECTRONIC PROPERTIES OF GRAPHITE OXIDE AND ITS POLYMER COMPOSITE

NANOFILMS Tamás Szabó, Imre Konfár, Judit Ménesi, Viktória Hornok and Imre Dékány, Department of Colloid Chemistry

and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vt. 1, 6720 Szeged, Hungary

Graphite/polymer composites are already known to have advantageous physicochemical properties, yet, advanced electronic and optical devices (sensors) can only be constructed if we are able to assemble these hybrid materials as ultrathin layers on a solid support. For the deposition of such films, the electrostatic self-assembly method is the best approach that requires hydrophilic and charged particles.

Since graphite itself does not stand these demands, we have controllably oxidized graphite by HNO3/NaClO3 to obtain graphite oxide (GO), which is hydrophilic and has negatively charged surface moieties. Thus, in contrast to graphite, it can be easily dispersed in aqueous solutions while retaining its layered structure. The chemical nature of GO and its dependence on the degree of oxidation have been revealed in detail by elemental analysis, XRD, FT-IR and EPR, indicating the formation of alcoholic and phenolic OH groups, with epoxide (1,2-ether) and –COOH groups on the carbon skeleton, and unoxidized graphitic regions. Ultrathin multilayer polymer/graphite oxide films were deposited on a glass support (a cationic polyelectrolyte, PDDA was used). The role of pH as well as the degree of graphite oxidation and the deposition time on the thickness and structure of the self-assembled layers was investigated by UV-Vis spectroscopy, XRD, TEM and AFM. The latter two imaging techniques revealed a crumpled conformation for graphite oxide. The insulator polyelectrolyte/GO assembly was transformed to a semiconductive graphitic nanofilm by reducing agents and heat treatment. Conductivity of deposited GO films was found to change strongly by incorporation of TiO2 particles between its carbonaceous layers.

E/PI.20 STRUCTURAL CHARACTERIZATION OF LITHIUM IODATE/LAPONITE NANOCOMPOSITE THIN

LAYERS Y. Lambert, J. Teyssier, R. Le Dantec, Y. Mugnier, C. Galez, J. Bouillot, LAIMAN, Université de Savoie, BP

806, 74016 Annecy Cedex, J.C. Plenet, LPMCN,Université Claude Bernard lyon 1 et CNRS, Bâtiment Léon Brillouin, 43 Boulevard du 11 novembre 1918, 69622 Villeurbanne, France

Lithium iodate/laponite nanocomposite thin layers have been elaborated for non-linear waveguiding applications. Layers are deposited on silicon or glass substrates by using dip coating technique from a solution made of a laponite colloidal suspension mixed with lithium iodate (LiIO3) aqueous solution. With a LiIO3/laponite volume ratio in the dry material ranging from 10 to 60%, transparent layers with thickness between 200nm and 3µm are obtained with this process. 2nd order non-linear optical properties in low cost waveguides are demonstrated showing a potential for frequency conversion applications.

The organization of individual Laponite particle (disk shaped crystals of about 30nm diameter and 1nm thickness) in a pure Laponite layer has been investigated with X-ray diffraction. Then, atomic force microscopy and polarized light microscopy has been used to understand the mechanisms of lithium iodate nanocrystals formation. Indeed, the drying of composite layers after the elaboration does not causes crystallization of lithium iodate dissolved in the inter-particles space. The nucleation of LiIO3 crystals occurs after annealing and the growth of the crystals is limited to nanometer size (30 to 50nm) by the confinement in the laponite matrix. In addition to the large natural orientation of individual Laponite particles parallel to the surface, a preferential orientation of the LiIO3 nanocrystals x-axis perpendicular to the layer plane has been observed. Moreover, a control of the nanocrystals orientation can be achieved by applying an external electric field during the annealing (ie nucleation) leading to increase and optimize the non-linear optical properties of the nanocomposite.

E/PI.21 NANOCOMPOSITES PAN-PANI OBTAINED IN THERMOCENTRIFUGAL FIELDS S. Vulpe, Ioan Stamatin, F. Nastase, Claudia Nastase, G. Stoian, 1University of Bucharest, Polymer Science

Department,P.O. Box MG-11, 077125 Magurele - Bucharest, Romania 2Advanced Reserch Institute for Electrical Engineering, Splaiul Unirii 313, Bucharest, Romania

EMI-shielding, anticorrosion, antistatic, trace detector for radiation particles remain an open subject for nanocomposites to find appropriate solution. In many practical aspects need, ready for use thin foils and bundle

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nanofibriles in ropes where the properties should be combined with high mechanical strength and thermal stability. In this respect, we report a method to obtain nanocomposites films using deposition in thermocentrifugal field of the polyacrylonitrile with ultrahigh dispersion of Polyaniline. The films have a very good anisotropy in electrical conduction over percolation threshold determined by chain orientation. XRD, FT-IR, AFM and Raman used for characterizations show a high degree of orientation of the macromolecular chains and follow same anisotropy as in electrical conductivity. The films have strong attenuation in large frequency range from KHz to GHz. The thermal stability measured by DTA/DTG up to 600K evidenced no structural changes.

E/PI.22 DIRECT MEASUREMENT OF THE INTERACTION BETWEEN MICA SURFACES WITH ADSORBED

STAR POLYMERS Y. Hiotelis(a), G Sakellariou(a), C. Toprakcioglu(a), N. Hatzichristidis(b), A.A. Vradis(a), (a)Department of

Physics, University of Patras, Patras 26500, Greece, (b)Department of Chemistry, University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece

We have measured the force-distance profiles between two curved mica sheets bearing end-functionalized polystyrene of different molecular weights M and architectures in good solvent (toluene). The polystyrene molecules are end-capped with a small butadiene oligomer terminating in a zwitterionic end-group (PS-X, where X represents the zwitterionic entity). We have studied polystyrenes with one, two, and three zwitterionic groups (PS-X, PS-X-X, and PS-X-X-X) as well as polystyrenes with one, two, and three tails, but only one zwitterionic end-group (PS-X, PS-PS-X, PS-PS-PS-X). The polymers adsorb on mica via these end-groups while the PS tails dangle in solution. We find that the presence of multiple zwitterionic end-groups has little effect on the adsorbance of the polymers on mica. We find a layer thickness dependence on molecular weight as in past studies (L0~M0, 6) and increase of mean interanchor spacing with M. The chain architecture seems to influence the interanchor spacing and the force profile, especially for PS-PS-PS-X. The presence of more than one tail per macromolecule has a strong influence on the adsorbance as well as the force-distance profile. This is attributed to the extra chain stretching caused by the close proximity of the multiple tails, which leads to a lower surface coverage

E/PI.23 POLY(CAPROLACTONE-CONTAINING BIPYRIDINE RUTHENIUM COMPLEXES AND QUADRUPLE

HYDROGEN-BONDING MOIETIES FOR DYE-SENSITIZED SOLAR CELLS Veronica Marin, Elisabeth Holder and Ulrich S. Schubert, Laboratory of Macromolecular Chemistry and

Nanoscience, Eindhoven University of Technology (TU/e), P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands

Recently Kim et al. reported successful results on the fabrication of a quasi-solid-state dye-sensitized solar cell based on a hydrogen-bonded poly(ethylene glycol) electrolyte (for comparison: 0.07% efficiency when employing high molecular weight PEO, and 3.34% for the case of the supramolecular PEO).

Motivated by this development we have synthesized a polymeric bipyridine functionalized with a quadruple hydrogen-bonding unit which will be further used for the synthesis of a Grätzel type ruthenium(II) complex. In addition a model compound has been synthesized. The synthesis of the poly(e-caprolactone)-containing bipyridine functionalized with a hydrogen-bonding unit is straightforward. The ureidopyrimidinone building block has been prepared in bulk from 2-amino-4-hydroxy-6-methylpyrimidine using an excess of 1,6-hexyldiisocyanate. Subsequent reactions with the poly(e-caprolactone)-containing bipyridine in the presence of dibutyltindilaureate resulted in the formation of the supramolecular bipyridine. Characterization was carried out by IR, UV-vis and 1H-NMR spectroscopy. The integration of the ruthenium precursor into the polymeric ureidopyrimidine-functionalized bipyridine could be easily checked by UV-vis spectroscopy: one can notice the appearance of the characteristic metal-to-ligand charge transfer band for a trisbipyridine-ruthenium(II) species at around 450 nm.

E/PI.24 SYNTHESIS AND CHARACTERIZATION OF HIGHLY PREFERRED ORIENTED LEAD BARIUM

TITANATE THIN FILMS USING ACETYLACETONE AS CHELATING AGENT IN A SOL-GEL PROCESS Wein-Duo Yang, Department of Chemical Engineering, National Kaohsiung University of Applied Sciences,

Kaohsiung 807, Taiwan, ROC and Sossina M. Haile Materials Science 138-78, California Institute of Technology, Pasadena CA 91125, USA

Ferroelectric (Pb1-x,Bax)TiO3 (PBT) materials can be synthesized by a sol-gel process incorporating acetylacetone as a chelating agent to form ligand with titanium isopropoxide. It was found that at a lower content of water, a slower rate of hydrolyzation occurred, which caused to a slower shift rate in the condensation. Therefore, a less cross-linking gel that pyrolyzed easily was observed. This less cross-linking gel could be converted to perovskite phase at temperatures as low as 450 oC. A high purity of (Pb0.5,Ba0.5)TiO3 powder was obtained at 500 oC, with a nano-meteric size of about 30-50 nm the specific surface area of 21.91 m2/g. Furthermore, a highly oriented PBT thin films were obtained by utilizing the as-prepared sol spin-coating on (100) MgO substrate. The oriented films were synthesized from all compositions between x = 0.2 and x = 0.8, at a crystallization temperature of 600 oC. In particular, for the Ba content in the range of x = 0.5~0.6, highly preferred (001)/(100) planes were observed.

E/PI.25 INVESTIGATION OF POROUS SILICON COMPOSITION AND MORPHOLOGY T.I. Gorbanyuk, A.A. Evtukh, V.G. Litovchenko, V.S. Solnsev Institute of Semiconductor Physics, National

Academy of Science of Ukraine, 41 prospect Nauki, 03028 Kiev, Ukraine The study of hydrofluoric acid concentration influence on the resulting microstructure and composition of porous

silicon by scanning electron microscopy (SEM) and Fourier transform infra-red (FTIR) spectroscopy has been performed. If the current density was kept constant, the microstructure of the porous layers changes with variations of HF concentration in electrolyte. The SEM investigations and the FTIR transmission spectra reveal the different types of porous silicon formed under various anodization conditions, namely: (a) the polymerized nanoporous films formation under high HF concentration; (b) the nanocrystalline porous silicon formation under weak HF solution. Fourier transform IR investigation confirms that the surface of polymerized nanoporous films silicon was covered by hydride. Secondary ion mass spectrometry observations correlated with IR data for these samples. The interference, observed on FTIR spectra, indicates that the polymerized nanoporous films are rather homogeneous. The nanocrystalline porous silicon layers exhibit the completely difference of microstructure from polymerized nanoporous films. Such layers was oxidized very fast and, as a result, on FTIR spectra we can see the increase in the oxide peaks. The model of polymerized nanoporous and nanocrystalline porous silicon growth have been proposed. Also comparative photoluminescence studies on different types of porous silicon was carried out.

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E/PI.26 EFFECT OF ALUMINIUM CONCENTRATION ON EXTENDED STATES IN RANDOM DIMER-BARRIER AlxGa(1-x)N/GaN SUPERLATTICES

H. Dakhlaoui and S. Jaziri We study in this paper electron transmission in AlxGa(1-x)N/GaN superlattices with structural short range-

correlations in the Al mole fraction of the AlxGa(1-x)N layers. The Al fraction in the equal width AlxGa(1-x)N layers takes at random three different values. We find that the superlattice contains two types of extended states; one of them is obtained from resonnance effects at dimmer barriers, while the other type arises as a consequence of the nature of this structure. The nature of the transition between these two regimes is investigated relevant physical quantities

E/PI.27 NOVEL “TRANSROTATIONAL” MESOSTRUCTURES IN CRYSTALLIZING AMORPHOUS FILMS V. Yu. Kolosov, Physics Dept., Ural State Economic University, 8th March St. 62, 620219 Ekaterinburg, Russia In recent 20 years the growing interest has been observed to the unusual (for condensed matter physics) structures:

quasi-crystals, fullerenes, nanotubes and derivatives thereof. In this paper we present other, less known unusual crystal aggregates: "transrotational" crystals with regular internal lattice bending observed as a result of amorphous-crystalline transformations in thin (10-100 nm) films of different chemical nature, produced by various methods. The main data are obtained by transmission electron microscopy (TEM), involving bend-contour method and in situ studies, combined with atomic force microscopy in due cases.

Unusual "transrotational" atom ordering (translation accompanied by small rotation, see fig. 7b [1]) results in strong regular, dislocation independent internal bending of the crystal lattice planes during crystal growth in amorphous film. The geometry (cylindrical, ellipsoidal, toroidal, saddle-like, etc.,) and the magnitude of lattice bending depend upon the substance, film preparation and crystallization conditions, orientation of the crystal nucleus and lattice symmetry, sublayers, composition and thickness. The most distinctive features of the structure appear at the meso scale (around 100 nm) where strong regular rotation (up to 10-30 degrees) of the lattice is attained. At the nano scale and at the micro scale it is often difficult to distinguish such structure by TEM from the normal deformed lattice (misorientations are too small) and fine-grained textured structure (disorientations are too large) accordingly. 1. V.Yu. Kolosov and A.R. Tholen, Acta Mater. v. 48 (2000), p. 1829. This work is supported by INTAS (00-100), pending support from RFBR (04-02-96072/05-02-17214).

E/PI.28 ELABORATION AND CHARACTERIZATION OF Bi2Sr2CaCu2O8+δ

N. Boussouf, M.-F. Mosbah, A. Ait-Kaki, F. Bouaicha, S. Chamekh., Université Mentouri de Constantine, Laboratoire de Couches Minces et Interfaces, Campus de Chaabet-Erssas, 25000 Constantine, Algérie

The conditions of preparation the samples Bi2212are found to improve their properties. These samples were synthesized by solid state reaction technique in air. The formation of superconducting and their microstructure were studied using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM).The content phase has been determined by use of XRD peak intensities.The superconducting transition temperature Tc was determined from resistivity measurement. The effect of sintering temperature and time leads to decrease the content of secondary phases such as Bi2201, CuO, Bi4413, CaCO3 The intergrowth layer of Bi2201 within the Bi2212 grains is evaluated by changes of 00l reflections in XRD. The unit cell constants change by sintering temperature. The morphology of plate-like particles microstructure seen by SEM is characteristic of superconductors phases.

E/PI.29 CHARACTERIZATION BY INFRA-RED TRANSMITTANCE SPECTROSCOPY OF TEXTURED BORON

NITIDE THIN FILMS SYNTHESISED BY PECVD P. Thévenin(a), M. Eliaoui(a,b), A. Ahaitouf(b), A. Bath(a), (a)LMOPS-Supelec, 2 rue E. Belin, 57070 Metz,

France, (b)FST Fès-Saïs, University of Fès, BP 2202, Fès, Marocco We have developped a program to calculate the optical transmittance of a thin film, which is based on the classical

parallel plate model, and which workes at normal as well as oblique incidence. The calculation includes the Fresnel coefficients as well as the refraction angles in their complex expressions. This program is used to analyse experimental IR transmittance spectra of boron nitride layers deposited onto silicon by PECVD. The optical response of the material is taken into account thanks to the dispersion equation of its permittivity, and in order to fully fit the measurements we also have to consider the texturation of the film.

The calculated results are in very good agreement with the experimental spectra, the most important adjustement parameter being the angle of preferential orientation of the nanocrystallites in the film. This later is shown to depends on the deposition process. This model can be applied to all uniaxial anisotropic media, and it offers a very simple and non destructive method to investigate the texturation of a film.

E/PI.30 MORPHOLOGICALLY DEPENDENT STRUCTURAL PECULIARITIES OF Ce-Zr-Al-O SYSTEM E. Frolova, M. Ivanovskaya, Y. Kosareva, Research Institute for Physical Chemical Problems, BSU,

Leningradskaya str. 14, 220050 Minsk, Belarus Alternative ways to high temperature solid-state reactions for producing of mixed oxides afford the sol-gel and

related soft chemistry methods that used solutions in the initial step of the preparation process, which leads to the many advantages. Herein we report on successful preparation of the Ce-Zr-Al oxide thin films and highly porous glassy products by a totally inorganic sol-gel technique. TEM, XRD, FTIR, ESR, UV-Vis, PL and XPS methods were used to investigate the structural composition and some properties of the morphologically different Ce-Zr-Al-O samples that are conditioned by different preparation techniques. TEM data show no visible difference in all dried in air at 50oC Ce-Zr-Al-O samples. However the further thermal treatment of the samples reveals the significant distinction in their properties dependent on their morphology. Indeed, ESR data of the obtained films, glasses and powders indicate the appearance of the Ce3+-defects with morphologically dependent concentration, that rich it’s maximum (~2·10/sup.18 spin/g) in the powdered samples. XRD investigation confirmed the considerable shift in crystallization process to the higher temperature going from powder to glasses (500 and 900oC) resulting in c-ZrxCe1–xO2 solid solution for all types of samples. No structural changes happened during further heating of the films and glasses up to 1200oC during 8 h in air, while the powdered samples are appeared to be three-phase system.

The work was supported by INTAS (grant 01-2162). E/PI.31 MESOSTRUCTURED THIN FILMS DEPOSITED BY PECVD FROM TMGE P. Kazimierski, echnical University of Lodz, Faculty of Process and Environmental Engineering, 90-924 Lodz,

Wolczanska 215, Poland The Plasma Enhanced CVD (PECVD) is proposed as an effective tool for preparation of the mesostructured thin

films. The technique is compatible with silicon technology what makes it interesting from potential application

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point of view. Thin layers deposited by this method, using tetramethylgermane (TMGe) as a source compound, can be deposited in forms characterized by various structure in nanometer-scale range. Depending on the process parameters both homogenous distribution of carbon and germanium atoms in the material as well as specific nanostructure with germanium and carbon reach regions can be fabricated. The structure differences have an obvious impact on the electronic properties of the material and results in two kinds of electronic structure - namely amorphous insulator (a-I) and amorphous semiconductor (a-S) respectively. The two-level-structure has been observed in the a-S films. The first level consists of germanium grains (few nm size)embedded in the carbon matrix. The grains are not randomly distributed in the material but agglomerate forming domains of about 60 nm in size defining the second level structure.

The paper concentrates on the deposition technology which leads to the a-S films and presents results of investigations implying the existence of the mesostructure in this material. Among applied experimental techniques the most interesting results have been achieved by: Raman spectroscopy, impedance spectroscopy and charge sensitive scanning probe microscopy (SPM).

E/PI.32 STRUCTURAL AND OPTICAL INVESTIGATIONS OF AS-GROWN AND ANEALED Cu-DOPED CdTe

THIN FILMS M. Rusu, G.G. Rusu, M. Girtan, “Al. I, Cuza” University, Faculty of Physics, Blvd. Carol I 11, Iasi 700506,

Romania An essential problem in technology of CdTe thin films is the control of the films stoichiometry. Depending on the

preparation conditions, these films may contain in excess one or other of the components. This fact strongly influences the physical properties of respective films. A possibility to decrease such excess is to include into the films, during their preparation, of some chemical elements in a convenient approach.

Our previous studies revealed that an inclusion of amount of cooper into CdTe thin films evaporated onto unheated glass substrates determines a decrease of the tellurium excess. In present paper we investigate the structure and optical properties of such CdTe doped films. Films with thickness about 900 nm were evaporated under vacuum onto unheated glass substrates using the stacked layer method. During deposition process, the substrates holder periodically passed in front of two separately evaporation sources for CdTe and Cu, having the temperatures of 925 K and 1200K respectively. Structural analysis revealed the X-ray diffraction characteristics of the cubic CdTe structure, with [111] preferential orientation parallel to the substrate, without additional peaks for Cu or Te structures. The heat treatment determines an improvement in the crystallinity of the films. In the paper, the effect of thermal annealing on the transmission and absorption spectra of the films are also studied. The energy gap value of 1.49 eV, deduced from absorption spectra, is in good agreement with those for bulk CdTe crystal.

E/PI.33 SYNTHESIS, STRUCTURE AND SOME PROPERTIES OF Fe2O3-In2O3 THIN FILMS M. Ivanovskaya, D. Kotsikau, Research Institute for Physical Chemical Problems of the Belarusian State

University, 14 Leningradskaya, 220050 Minsk, Belarus, A. Taurino, S. Capone, P. Siciliano, Institute of Microelectronics and Microsystems, IMM-CNR, Lecce Department, Via Arnesano, 73100 Lecce, Italy

Composites based on iron oxide find applications in different areas due to their advanced magnetic, optical and adsorption-catalytical properties. Structural peculiarities and some properties (electrical conductivity, gas sensitivity) of Fe2O3-In2O3 (Fe:In 9:1, 1:1, 1:9) thin films, obtained by sol-gel method, have been studied in this work. Technical approaches, which provide the formation of films, consisting of oxide phase grains with the size of 2-8 nm, were proposed. The structure of the films was studied by TEM, ED and Mössbauer Spectroscopy. The synthesis conditions, allowing to stabilise nonequilibrium gamma-Fe2O3 phases with either cubic or tetragonal symmetry in highly dispersed Fe2O3-In2O3 composites, were revealed. The influence of both grain size and phase composition of Fe2O3-In2O3 composites on electrical conductivity and gas-sensing properties of the corresponding thin-film layers (100 nm), deposited onto micromachined Si-substrates, were considered. A considerable distinctions in adsorption and gas-sensing behaviour of Fe2O3-In2O3 films, containing different structural modifications of iron oxide (cubic, tetragonal and hexagonal), as well as Fe-In2O3 and In-Fe2O3 solid solutions, were achieved.

E/PI.34 ADSORPTION PROCESS IN LAYER-BY-LAYER FILMS OF NITSPC AND PAH Nara C. de Souza(a), Josmary R. Silva(b), Osvaldo N. Oliveira Jr.(b), José A.Giacometti(a), (a)Depto. de Física

Química e Biologia, Faculdade de Ciências e Tecnologia, Universidade Estadual Paulista, CP 467, 19060-900, Presidente Prudente/SP, Brazil, (b)Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970,São Carlos/SP, Brazil

The investigation of adsorption processes in layer-by-layer (LBL) films obtained with ionic attraction of oppositely charged layers is important not only for the characterization of such films but also for the design of new molecular architectures with improved properties. In this work we monitor the adsorption of tetrasulfonated nickel phthalocyanine (NiTsPc) and poly(allylamine hydrochloride) (PAH/NiTsPc) LBL films using UV-vis spectroscopy. The kinetics of adsorption of NiTsPc displayed the usual monotonic increase in the amount of material adsorbed with time, with the results being interpreted with a 2-step adsorption process. The first step could be represented by a first-order kinetics while the second one was fitted with a Johnson-Mehl-Avrami (JMA) function, with the Avrami parameter n  1.5. Multilayers could also be built, with the absorption in the UV-VIS. spectra increasing with the number of PAH/NiTsPc bilayers deposited on the glass substrate. In order to be able to neglect substrate effects, the adsorption process was also investigated for a NiTsPc layer deposited on top of 10 PAH/NiTsPc bilayers.

E/PI.35 SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF NANOSTRUCTURED La1-xCaxMnO3/ C60

THIN FILMS COMPOSITES O. Pana(a), C. M. Teodorescu(b), D. Macovei(b), R. Turcu(a), Al. Darabont(c), M.L. Soran(a), (a)National

Institute R&D for Isotopic and Molecular Technologies, PO Box 700, Cluj-Napoca, Romania, (b)National Institute R&D of Materials Physics, P.O.Box MG-7 Bucuresti-Magurele, Romania, (c)“Babes-Bolyai” Univ. of Cluj, Faculty of Physics, 1 Kogalniceanu str. Cluj-Napoca, Romania

There were various approaches to synthesize and characterize fullerene based composites with various magnetic and non-magnetic metals.

The aim of the present study is focused on the synthesis and structural characterization of the nanostructured La1-xCaxMnO3 (LCMO)/ C60 thin films by using the co-evaporation method on chemically etched Si(100) substrates. More precisely, fullerene molecules were obtained by sublimation from a Knudsen cell at 520 - 570 °C, whereas the LCMO composite is evaporated by electron bombardment from a Ta crucible hit by a current 50 - 100 mA of electrons accelerated at 1.5 - 2.5 keV. The relative concentration of composite and fullerite is obtained by variation of the relative deposition rates, as measured by a quartz microbalance with typical error is less than 1 %. The

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LCMO concentration ranges between 2 % and 35 %. SEM and EDX methods are used to investigate the surface morphology and composition of the material. Comparative structural peculiarities of both LCMO and LCMO)/ C60 thin films are analyzed by using X-ray diffraction in order to determine the lattice strain and disorder of the fullerite, and, in correlation with the electron microscopy, the average size of nanoparticles embedded in the fullerite matrix. Further, XPS investigations gives additional information on (i) relative composition of the deposited layers, (ii) chemical (oxidation) states of the components; (iii) charge transfer occurring between composite nanoclusters and the surrounding fullerite matrix and (iv) surface states of the composite nanoparticles. Comparisons of magnetoresistance and magnetic susceptibility behaviors vs. temperature between bulk LCMO and LCMO / C60 thin films composites are also evidenced.

E/PI.36 PREPARATION AND CHARACTERISATION OF CdSe/Cu MULTILAYERED THIN FILMS C. Baban, G.G. Rusu, M. Girtan, “Al. I, Cuza” University, Faculty of Physics, Blvd. Carol I 11, Iasi 700506,

Romania CdSe/Cu multilayered films were deposited onto glass substrates using vacuum evaporation. Cu and CdSe were

evaporated from different sources and the substrate holder was rotated making the substrate to pass successively in front of Cu and CdSe evaporators. Simultaneously, Cu and CdSe thin films were prepared for reference.

The electrical conductivity of CdSe/Cu films is high and can be determined by the existence of Cu layers inside the sample. The temperature dependence of electrical conductivity is typical for semiconducting materials and is determined by the CdSe layers. After annealing at 300oC the conductivity is decreasing. As deposited samples show small transmission and high reflectance. After annealing at 300oC the transmission increases up to 70 % while the reflectance decreases. For the as deposited samples, both electrical and optical properties can be determined by the multilayer structure of the films. For annealed samples the results can be explained by Cu diffusion into adjacent CdSe layers.

E/PI.37 TITANIUM NITRIDE NANOTUBES GROWN BY REACTIVE MAGNETRON SPUTTERING M.A. Auger(a), O. Sánchez(a), M. Hernández-Vélez(a,b), D. Navas(a), M. Jaafar(a), R. Sanz(a), K. R. Pirota(a),

A. Asenjo1 and M. Vázquez(a), (a)Instituto de Ciencia de Materiales de Madrid (CSIC).Cantoblanco 28049 – Madrid. Spain, (b)Departamento de Física Aplicada - C-XII, Universidad Autónoma de Madrid, Cantoblanco 28049 – Madrid, Spain

Development of new methods in the formation of hollow structures, in particular, nanotubes and nanocages are currently generating much interest as a consequence of the growing relevance of these nanostructures on many technological fields, ranging from optoelectronics to biotechnology. Different processes have been developed to achieve this goal and the most commonly used approaches are based in arc-discharge and laser ablation methods, in which the main disadvantage is that the substrates are exposed at high temperatures. In this work, we report the formation of Titanium Nitride (TiN) nanotubes via reactive sputtering magnetron processes. Anodic Alumina Membranes (AAM) were used as template substrates for growing the TiN nanostructures. The AAM were obtained through electrochemical anodization processes by using oxalic acid solutions as electrolytes. These highly ordered templates displayed nanoporous sizes between 30 and 60 nanometers and interpore distances around 100 nanometers. The nanotubes were produced at temperatures below 100ºC, and using titanium of a purity of 99.99% as sputtering target and nitrogen as reactive gas. After the TiN growth mechanical and electrochemical techniques were used to detach the TiN nanostructure from the nanoporous alumina substrates. High Resolution Scanning Electron Microscopy (HRSEM) and Atomic Force Microscopy were used to elucidate both the surface order and morphology of the different nanostructures that were grown. The crystalline structure of the samples was examined using X-ray Diffraction patterns (XRD) and their chemical composition by using X-ray Energy Dispersive Spectroscopy (EDX) in a scanning electron microscopy. Finally the formation of highly ordered Titanium Nitride Nanotubes with inner diameters in the range 20 - 50 nm is demonstrated.

E/PI.38 CHANGES IN CORE-LEVEL AND VALENCE BAND SPECTRA OF GOLD PARTICLES UPON THIOL

ADSORPTION AS A FUNCTION OF THE MEAN PARTICLE SIZE M. Büttner, P. Oelhafen, Department of Physics, University of Basel, Klingelbergstr. 82 , 4056 Basel, Switzerland Electronic properties of gold nanoparticles are of great interest due to their potential application in electronic and

optical devices. Despite the wide-spread use of chemically synthesized monolayer-protected particles, the interaction of the metal core with the various passivating molecules is not fully understood. Thiol molecules are a often used as a ligant shell, as they easily bind to gold surfaces via their sulfur headgroup. In this work, we investigate the influence of the sulfur-gold interaction on the electronic properties of the gold particle.

Gold nanoparticles have been grown on carbon substrates by thermal evaporation of the bulk metal. The mean particle size has been varied by depositing different amounts of gold. In a next step, thiol molecules (hexadecanethiol) have been adsorbed on the sample by exposure to a thiol atmosphere (1x10e-6 mbar) for one hour. This was done without breaking the vacuum, as the thiol was introduced into the vaccum chamber through a leak valve. Between each preparation step gold and sulfur core-levels and valence band spectra have been obtained by monochromated X-ray Photoelectron Spectroscopy. Our results show a positive shift of the Au 4f core-level binding energies after thiol exposure which is increasing with decreasing particle size.. The corresponding valence band spectra present a distinct change in line shape due to thiol adsorption. We will comment the possibility of a sulfur-induced metal-insulator transition in the gold particles.

E/PI.39 VAPOR INFILTRATION TECHNIQUES FOR SPIN-ON MESOPOROUS SILICA FILMS Shunsuke Tanaka(a), Hiromi Tada(a), Norikazu Nishiyama(a), Yoshiaki Oku(b), Yasuyuki Egashira(a) and

Korekazu Ueyama(a), (a)Osaka University, (b)ASET-MIRAI project, Japan Spin-coating method is a simple way to synthesize nanostructured silica films. However, the thin films by spin-

coating have low thermal stability because the reactions proceed at room temperature. In this study, we have developed a vapor treatment using a silica source for spin-on nanostructured silica films to improve the structural stability. The vapor treatment promotes condensations of silanol groups. The silica wall is densified and hardly contracts under a calcinations process. This result indicates that vapor treatments effectively enhance structural stability. We have studied effect of vapor treatments on mechanical strength and hydrothermal stability of the nanoporous silica films prepared from tetraethoxysilane (TEOS)/Brij 30 (C12(EO)4) mixtures. The results of pressure tests and hot water-resisting tests show that the vapor-treated films exceed non-treated films in mechanical strength and hydrothermal stability. The vapor-treated nanoporous silica films are promising materials as low-k films with high mechanical strength and high porosity.

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E/PI.40 ACID-BASE POST-SYNTHESIS TREATMENTS EFFECTS ON MESOPOROUS THIN FILMS TEMPLATED BY P123: STRUCTURAL STUDIES

Jean-François Bardeau(a), Agnès Gourbil(a), Maggy Dutreilh-Colas(a), Sandrine Dourdain(a), Ahmad Mehdi(b), and Alain Gibaud(a), (a)Laboratoire de Physique de l’Etat Condensé, Faculté des Sciences, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans Cedex 09, France, (b)Laboratoire de Chimie Moléculaire et Organisation du Solide, Université de Montpellier II, UMR 5637 CNRS, Place E. Bataillon, 34095 Montpellier Cedex 5, France

The aim of this work is to show the effects of post-synthesis treatments on the structured mesoporous films and to verify the possibility to stabilize structured materials without coating the pore interiors or grafting molecules onto the pore surface. We present the effects of a series of ambiant temperature acid-base post-synthesis treatments on 2D hexagonal mesoporous silica thin films templated by PEO/PPO/PEO (polyethylene oxide/polypropylene oxide) triblock copolymer (P123). The films were prepared by dip-coating a cleaned glass slide onto an alcoholic acid solution of TEOS and Pluronic P123. Then, the different post-treatments were introduced in the procedure before rinsing the mesostructured films in ethanol to remove the surfactant. The evolution of the 2D hexagonal structures was investigated by X-ray Reflectivity before and after removing the surfactant from the silica matrix. X-ray reflectivity curves exhibit Kiessig fringes and Bragg reflections related to the total thickness of the film and the internal well-organized multilayers, respectively. The detailed effects of post-synthesis treatment on the structural order have been deduced from the full analysis of the X-ray reflectivity curves. The evolution of cell parameters, average electron densities of the films, wall thickness and electron densities of the walls will be presented for treatments which do not affect too much the structure.

E/PI.41 INTERACTION OF SMALL AMOUNTS OF BOVINE SERUM ALBUMIN WITH PHOSPHOLIPIDS IN

LANGMUIR MONOLAYERS AND LANGMUIR-BLODGETT FILMS Nara C. de Souza(a), Wilker Caetano(b), Marystela Ferreira(a), Rosangela Itri(b), Osvaldo N. Oliveira Jr.(c), José

A. Giacometti(a), (a)Depto. de Física Química e Biologia, Faculdade de Ciências e Tecnologia, Universidade Estadual Paulista, CP 467, 19060-900 Presidente Prudente/SP, Brazil, (b)Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970, São Paulo/SP, Brazil, (c)Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970,São Carlos/SP, Brazil

The influence from small amounts of the protein bovine serum albumin (BSA) on lateral organization of phospholipid monolayers at the air-water and air-solid interfaces was investigated. The kinetics of adsorption of BSA onto the phospholipid monolayers was monitored with surface pressure isotherms in a Langmuir trough, for the zwitterionic dipalmitoyl phosphatidyl ethalonamine (DPPE) and the anionic dipalmitoyl phosphatidic acid (DPPA). A monolayer of DPPE or DPPA incorporating BSA was transferred onto a solid substrate using the Langmuir-Blodgett technique. Atomic force microscopy (AFM) images of the one-layer LB films displayed protein-phospholipid domains, whose morphology was characterized using dynamic scaling theories to calculate roughness exponents. For DPPA-BSA films the surface is characteristic of self-affine fractals that may be described with the Kardar-Parisi-Zhang (KPZ) equation. On the other hand, for DPPE-BSA films the results indicate a relatively flat surface within the globule. The height profile and the number and size of globules varied with the type of phospholipid. The overall results, from kinetics of adsorption in Langmuir monolayers and surface morphology in LB films, could be interpreted in terms of the higher affinity of BSA to the anionic DPPA than to the zwitterionic DPPE.

E/PI.42 ANISOTROPICALLY CONDUCTING LANGMUIR-BLODGETT FILMS FABRICATED IN MAGNETIC

FIELD A.I. Alexandrov, A.V. Krasnov, T.V. Pashkova, Ivanovo State University, Ermak St, 39, Ivanovo 153025, Russia Langmiur-Blodgett techique allows to create structures with monoaxial orientational order in the absence of

macroscopic molecular orientation along layers. Use of paramagnetic molecules of some lanthanide metallomesogens in a planar magnetic field allows to create biaxial textured LB films [1]. This approach has underlain the method of LB films fabrication with azimuthal anisotropy of planar electric conductivity.

For creation of anisotropically conducting LB films paramagnetic molecules of terbium complex with Schiff base ligands and dodeciloxysulphate counter ions were used for orientation of diamagnetic complexes with ionic transport on the base of crown-ether and sodium laurate(guest-host effect). Applying of a relatively weak planar magnetic field results in orientation of guest-host system molecules on water surface. Molecular orientation on air-water interface stimulated by a magnetic field is saved in LB films fabricated of magneto modified monolayers that is proved by means of electron diffraction. Electron diffraction patterns obtained from magneto modified LB films show the existence of biaxial texture. The expected existence of azimuthal anisotropy of planar electric conductivity in the investigated LB films is proved by direct measurements of conductivity in different azimuthal directions. [1] Alexandrov A.I., Krasnov A.V., Pashkova T.V., Syn. Met., Vol.147/1-3(2004), pp.205-208.

E/PI.43 ADSORPTION-DESORPTION ISOTHERMS OF NANOPOROUS THIN FILMS MEASURED BY X-RAY

REFLECTOMETRY M. Klotz, Laboratoire CNRS/Saint-Gobain “Surface du Verre et Interfaces” UMR 125, 39 quai Lucien Lefranc,

BP 135, 93303 Aubervilliers Cedex, France, D. Rébiscoul, CEA-LETI, D2NT/LBE, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France, A. van der Lee, V. Rouessac, J. Durand and A. Ayral, Institut Européen des Membranes, UMR 5635, CNRS-ENSCM-UMII, CC047, Université Montpellier II, 34095 Montpellier Cedex 5, France

An attractive method for the characterisation of the porosity of thin films is proposed. The adsorption and desorption of vapour is coupled to the measurement of the thickness and of electron density of the films by X ray reflectometry. The variation of the density by vapour adsorption and capillary condensation enables us to determine the amount of adsorbed vapour as a function of the solvent relative pressure and therefore to draw adsorption-desorption isotherms. From these isotherms, the specific surface area, the pore size distribution, the total pore volume as well as the volume fractions of open and closed porosity can be determined. This method allows to overcome the limitation of the classical volumetric adsorption techniques successfully applied for powder or porous but requiring a large amount of sample. Moreover X-ray reflectometry is applicable with usual substrates, as long as the substrate is flat enough and its density is different from that of the supported film.

The isotherms of sol-gel derived silica coatings will be given as examples. The results will be compared with those determined from N2 adsorption-desorption measurements using a conventional volumetric apparatus and special cells containing a large number of coated slides.

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E/PI.44 ELECTRON SPIN RESONANCE OF SILICON NANO-WIRES B.D. Shanina(a), S.P. Kolesnik(a), T.I. Kamins(b), S. Sharma2, P.M. Lytvyn(a), A.I. Klimovskaya(a), G.V.

Beketov(a), I.V. Prokopenko(a), I.P. Ostrovskii(c), (a)Institute of Semiconductor Physics, Kyiv 03028 Ukraine; (b)Quantum Science Research, Hewlett-Packard Laboratories, Palo Alto CA 94304, USA; (a)State University “Lvivska Politehknika”, Lviv, Ukraine

Several sets of self-assembled silicon nanowires grown using two different catalytically enhanced methods are characterized using electron spin resonance, scanning electron microscopy, and x-ray diffraction. The nanowires were grown either in a sealed tube with bromine as transporting agent or in a gas-flow reactor using SiH4+HCl+H2; in the latter case, the nanowires were grown on Si (001) substrates. Some of the samples were highly doped by paramagnetic atoms (P31). Undoped samples of unattached nanowires show the resonance signal of dangling bonds with g=2.0055 and a signal of weakly bound electron states located under the nanowire surface. In doped samples a single line of P31 narrowed by exchange interaction, a spectrum of E-centers and a set of thermal defects are observed. In addition, anisotropy of P31 g-factor is found that indicates a compressive strain T in the nanowires. The dependence of g on strain is analyzed, and the value of T along the [100] direction is found: T=278 MPa. In addition, in all the samples with wires grown on a substrate, the resonance signal of acceptors from the boron-doped substrate is observed. In stress-free silicon, this signal is not observed due to degeneracy of the valence band. Its appearance here suggests a uniaxial strain of the substrate that is estimated from the value of g-factor to be 25 MPa.

E/PI.45 A NOVEL METHOD FOR THE PORE SIZE ANALYSIS OF THIN SILICA FILMS BASED ON KRYPTON

ADSORPTION AT LIQUID ARGON TEMPERATURE (87.27K) Matthias Thommes, Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach FL 33426, USA Thin mesoporous (silica) films have important applications in many fields (e.g., low-k dielectrics) and detailed

knowledge of the pore size distribution and pore volume is crucial in order to optimize their applications. Nitrogen and argon sorption at 77.4 K and 87.3 K are suited for conventional micro/mesopore size analysis, but cannot be applied for the pore size analysis of thin porous films. Because of the very small absolute surface area and pore volumes of such thin films, krypton adsorption has to be considered. However, the interpretation of krypton sorption data obtained on porous materials at 77.4 K and 87.3 K is not straightforward, because these temperatures are well below the bulk triple point temperature of krypton (Tr = 115.8 K)and the sorption, phase and wetting behavior in this temperature range is still subject of research.

In order to address these problems we (i) studied the effect of confinement on the phase behavior of krypton by performing sorption experiments at 87.3 K in mesoporous silica molecular sieves of different mean pore sizes (ii) further, we obtained from our experiments a clear correlation between the pore size (calculated by applying the NLDFT method on nitrogen and argon isotherms measured on the same samples used in the krypton studies) and the pore filling pressures of krypton. This unique calibration curve allows one to obtain an accurate pore size analysis of thin silica films from below 2nm up to ca. 10 nm (above which Kr pore condensation cannot be observed anymore), and the pore sizes obtained in this way are traceable to NLDFT pore size analysis. We will discuss the application of this new method on various mesoporous silica film samples.

E/PI.46 PHOTO-EMISSION-ELECTRON-MICROSCOPY FOR CHARACTERISATION OF ORGANIC

SEMICONDUCTROS AT APPLIED VOLTAGES Klaus Müller, Yevgen Burkov, Dieter Schmeißer, Brandenburgische Technische Universität Cottbus, Angewandte

Physik-Sensorik, 03013 Cottbus, P.O. Box 101344, Germany Characterisation with Photoemission-electron-microscopy (PEEM) is introduced as a tool for the characterisation

of organic transistor structures with channel lengths in the µm-range. Semiconducting regioregular Poly(3-Hexylthiophene-2,5-diyl) (P3HT) was deposited as thin film by spin coating. For the characterisation of the polymer at applied voltages, we use source-drain-electrode structures of different organic materials like carbon-black or graphite, plotted on a printing foil. For our PEEM-measurements we use illumination by a standard high pressure Hg-lamp (4.9eV), D2-illumination (7.3eV), and synchrotron radiation. PEEM enables a simultaneous analysis of the lateral distribution of electron densities. µPES at selected areas gives informations on the chemical homogeneity of the organic semiconductor in lateral resolution and the absolute values of surface potentials. PEEM images with applied voltages at the source- and drain-electrode, compared with UPS-spectra, gives informations on the electron densities, the chemical composition and the surface potential of the organic semiconductor. In conclusion, PEEM is shown to become a complementary method for characterization of the surface potential with Scanning-Kelvin-Probe-Microscopy (SKPM).

E/PI.47 MICROSTRUCTURAL STUDY OF SOL-GEL ZIRCONIA THIN FILMS USING X-RAY REFLECTIVITY,

DIFFRACTION AND GRAZING INCIDENCE SMALL ANGLE X-RAY SCATTERING P. Lenormand(a), A. Lecomte(b), D. Babonneau(c), A. Dauger(b), (a)Centre Interuniversitaire de Recherche et

d’Ingéniérie des MATériaux, Laboratoire de Chimie des Matériaux Inorganiques et Energétiques Université Paul Sabatier, Bât. 2R1,118 route de Narbonne, 31062 Toulouse cedex 4, France, (b)Science des Procédés Céramiques et de Traitements de Surface, CNRS UMR 6638, ENSCI, 47-73 av. A. Thomas, 87065 Limoges Cedex, France, (c)Laboratoire de Métallurgie Physique, UMR N°6630, Université de Poitiers - UFR Sciences, SP2MI, Boulevard Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil cedex, France

In the recent years, material science has been intense interest in the development of nanostructured oxide materials and more particularly in the form of thin films, leading consequently to renew a number of characterization techniques such as X-ray reflectometry (XRR), grazing incidence diffraction (GIDRX) or small angle X-ray scattering (GISAXS). In this study, we evidence that the combination of these three techniques is a relevant and powerful structural characterization tool to thin oxide films.

Continuous, homogenous and crack-free thin films of zirconia oxide, which is a key material in number of optic, optoelectronic and microelectronic potential applications, were synthesised on various mirror-polished substrates (glass, silicon and sapphire) by a sol-gel route using a dip-coating process in modified Zr n-propoxide solutions. Microstructural parameters of crucial importance like film thickness, density, crystalline phase, grain size and spatial correlation have been determined for various synthesis parameters such as Zr-alkoxide concentration, withdrawal speed and thermal treatments. During annealing at low temperature, 200-1000°C, the removal of organics induces a film thickness decrease while its density increases up to about 85% of theoretical density. Simultaneously, we observe the film crystallisation in the zirconia tetragonal form. The very narrow size distribution of the randomly oriented tetragonal zirconia crystallites leads to self-organized coatings with a close-packing structure. These nanostructured films, with typical thickness ranging from 20 to 100 nm, behave as conventional massive zirconia xerogels independently of the interface presence or the chemical nature of the substrates.

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E/PI.48 CHARACTERIZATION OF MESOSTRUCTURED TIO2 THIN LAYERS BY ELLIPSOMETRIC POROSIMETRY

V. Rouessac(a), F. Bosc(b), J. Durand(a) and A. Ayral(a), (a)Institut Européen des Membranes CNRS UMR5635 - ENSCM - UMII, CC047, 2 Place Bataillon, 34095 Montpellier cedex 5, France, (b)Laboratoire des Matériaux, Surfaces et Procédés pour la Catalyse CNRS UMR 7515 – ECPM –ULP, 25 rue Becquerel, 67 087 Strasbourg cedex 2, France

Isothermal ellipsometric measurements were carried out under controlled vapour pressure from vacuum to saturation on mesostructured anatase-based thin layers. Thin films were prepared by the sol-gel route using the templating effect of lyotropic mesophases. Ellipsometric porosimetry (EP) has been applied for analysing both as-deposited hybrid films and thermally treated films with an ordered mesoporosity resulting from the removal of the template. EP reveals that the behaviour of the dense hybrid films submitted to a solvent atmosphere is drastically different from that of the calcined layers with a rigid oxide skeleton and capillary condensation occurring in the mesopores. The EP results will be discussed and correlated with those of other analyses by conventional volumetric nitrogen adsorption-desorption and small angle x-ray diffraction coupled with nitrogen adsorption-desorption.

E/PI.49 OPTICAL PROPERTIES OF ORDERED MESOPOROUS SILICA LAYERS P. Cheyssac, Laboratoire de Physique de la Matière Condensée, UMR 6622 CNRS, Université de Nice Sophia-

Antipolis, France, M. Klotz, E. Sondergaard, Unité Mixte de Recherche CNRS/Saint-Gobain, Surface du Verre et Interfaces, Saint-Gobain, France

Mesoporous layers of silica are of interest for many optical applications, including the creation of devices ranging from optical sensors to laser sources with promising characteristics. Their optical characterization goes through the interpretation of measurements. We propose to give experimental results of reflectance and scattering measurements concerning mesoporous layers of silica deposited onto silicium substrates. This work shows that their interpretation in therms of optical indices or dielectric function have to be taken with care since scattering is present and thereby, the Kramers-Kronig relations appear not to be fulfilled.

E/PI.50 ELECTRICAL CONDUCTIVITY OF FREE-STANDING MESOPOROUS SILICON THIN FILMS M. Khardani, M. Bouaïcha, W. Dimassi, B. Bessaïs, Laboratoire de Photovoltaïque et des Semi-conducteurs,

Institut National de Recherche Scientifique et Technique, B.P. 95, 2050 Hammam-Lif, Tunisia

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Thursday, June 2, 2005 Morning Jeudi 2 juin 2005 Matin Session V : Nanoporous and/or textured layers Session chairs : Oswaldo L. Alves and Pilar Aranda E-V.01 8:30 -Invited- SYNTHESIS OF MESOSTRUCTURED ORGANOSILICA HYBRID FILMS S. Inagaki, Y. Goto, O. Ohtani, S. Fujita, Y. Kumai, M. Ohashi, Toyota Central R&D Labs.,

Inc., Nagakure, Aichi, 480-1192, Japan Periodic mesoporous organosilicas with integral organic functionality derived from bridged

organosilanes [(R'O)3Si-R-Si(OR')3] in the presence of surfactant have homogeneous distribution of organic fragments and silica moieties within the framework. The materials have uniform pores, higher stability, and control on morphologies and potential application in a variety of areas, including optoelectronics, sensing, enantioselective separation and catalysis. The main object of contemporary hybrid mesoporous materials synthesis is to control the geometry of a material at the molecular level and macro-scale level of design. Recently, we have succeeded in the formation of periodic arrangement of organosilica moieties in the pore walls exhibiting crystal-like 7.6 Å periodicity along the channel direction by using self-assembly of interactive phenylene-bridged organosilane precursors. The crystal-like mesoporous organosilicas are expected to exhibit unique optoelectrical properties and catalysis. Here, we report our recent studies on the modification of the crystalline mesoporous organosilicas with functional groups such as sulfonic groups, amine groups, amino acids and metal complexes for applications to electrolyte and catalysis. And, we also report the synthesis of coating thin film and self-standing film of mesoporous organosilicas.

E-V.02 9:00 MORPHOLOGY, MESOPORE, AND PARTICLE SIZE CONTROL OF

MESOCELLULAR FOAM VIA MODIFIED SYNTHESIS OF VARYING OPERATIONAL PARAMETER

W. Ratanachaithong(a,b,c), P. Hartley(a), M.L. Gee(b), G.W. Stevens(c), A.J. O’Connor(c), (a)CSIRO Molecular Science, Private Bag 10, Clayton, Victoria 3169, Australia, (b)School of Chemistry, The University of Melbourne, Victoria 3010, Australia, (c)Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010, Australia

A mesoporous siliceous material of MCF type was characterized by nitrogen adsorption, Coulter Particle Size Measurement, and Scanning Electron Microscopy. Its pore diameter, external and internal surface, pore volume, wall thickness, and pore wall density were determined.

Special attention was paid to the effect of varying aging temperature, stirring speed and mechanism on the particle size and its distribution. There is evidence that calcined mesocellular foam swell at lower aging temperature combined with an optimum stirring speed during its synthesis. By modifying the operational parameters during the synthesis, the particle size of silica can be continuously modulated from nanoparticle to micrometric spherical particles (up to 1m). In this way, the primary particle size of the obtained porous silica can be easily selected and controlled in a wide range between 30nm and 1000nm. (More results to be presented)

E-V.03 9:15 STUDY OF THE MICROSTRUCTURE, MECHANICAL PROPERTIES AND WEAR

BEHAVIOR OF THERMALLY SPRAYED ALUMINA-TITANIA COATINGS S. Guessasma, T. Sahraoui, Laboratory of study and research in materials, processes and

surfaces (LERMPS) - UTBM, Site de Sevenans, Belfort, France In this paper the relationship between the process parameters, microstructure, mechanical

properties and in-service properties of thermally sprayed alumina-titania coatings is investigated. Energetic parameters (arc current, plasma gas flow rate and hydrogen ratio) were varied to permit a significant variation of the microstructure features (porosity, phase ratios, unmolten particles). Mechanical properties namely hardness, Young modulus and adhesion were measured and correlated to the microstructure. These, in turn, were considered as a control factors with the microstructure for the study of the friction and wear behavior of the coatings using Pin-On-Disc arrangement. Statistical analysis of experimental results was carried out using artificial neural networks to improve the quantitative interpretation.

E-V.04 9:30 IMPACT OF MESOPOROUS MSQ CROSSLINKING ON MECHANICAL

PROPERTIES: APPLICATION TO MICROELECTRONIC INTERCONNECTIONS F. Ciaramella(a), V. Jousseaume(a), S. Maitrejean(a), M. Verdier(b), B. Rémiat(a), A.

Zenasni(a) and G. Passemard(c), (a)CEA-DRT-LETI, 17 rue des Martyrs, 38054 Grenoble cedex 9, France, (b)LTPCM, 1130 rue de la Piscine, 38402 Saint Martin d'Hères, France, (c)STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles, France

Due to integrated circuits performances increase, insulator materials with dielectric constant lower than 2.4 are requested for microelectronic interconnections. Porous organosilicate thin films are promising candidates for this application. Previous studies reported low mechanical properties for mesoporous MSQ films and these properties were usually modelized using cellular solids mechanic. In this work, a new approach based on MSQ crosslinking evaluation is proposed to understand mechanical properties of mesoporous organosilicate thin films. Several synthesis ways were used to deposit MSQ layers with different porosity and matrix crosslinking. The material structure was improved using different curing methods (furnace cure or UV assisted cure). Impact of deposition process and cures on crosslinking were investigated using FTIR analysis and spectroscopic

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ellipsometry. The mechanical properties were determined by nanoindentation. A correlation between mechanical properties and FTIR SiOSi contribution is observed for all the samples studied. A physical model is proposed which allow to predict mechanical properties with the matrix crosslinking.

E-V.05 9:45 ION IMPLANTATION OF NANOCAVITIES IN InP TO IMPLEMENT COMPLIANT

SUBSTRATES M. Chicoine(a), S. Roorda(a), P. Desjardins(a), and R.A. Masut(a,b), (a)Regroupement

québécois sur les matériaux de pointe (RQMP), Département de Physique, Université de Montréal and Département de Génie Physique, École Polytechnique de Montréal, CP 6079 succ. Centre-ville, Montréal PQ H3C 3A7, Canada, (b)Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Cantoblanco, 28049 Madrid, Spain

Room temperature He ion implantation and subsequent thermal annealing allows the introduction of a buried uniform layer of nanocavities in InP and other III-V compound substrates. We have developed a process to use these nanocavities to effectively decouple the thin upper layer of the substrate, in order to implement a compliant InP substrate for heteroepitaxy. Metalorganic vapor phase epitaxy of InAsP/InP heterostructures grown simultaneously on substrates with nanocavities and on conventional substrates were characterized by high-resolution X-ray diffraction, transmission electron microscopy, and optical absorption. The strain relaxation is enhanced for heterostructures grown on substrates with nanocavities and the dislocations propagate partly in the compliant layer instead of the epilayer. The critical thickness of heterostructures grown on conventional substrates is roughly double that of structures grown on substrates containing nanocavities.

E-V.06 10:00 NOVEL APPROACH TOWARDS SYNTHESIS OF MESOSTRUCTURED SnO2 THIN

FILMS USING SPRAY PYROLYSIS Young Kyu Hwang, Niranjan Ramgir, Hye-kyung Kim, Imtiaz S. Mulla and Jong-San

Chang, Research Centre for Nanocatalysts (RCNC), Korea Research Institute of Chemical Technology (KRICT), Yuseong, Korea

Pure and Pt-doped mesostructured SnO2 thin films were successfully prepared using non-anionic surfactant Brij-58 (polyoxyethylene acyl ether) as organic template and tin tetrachloride and hydrogen tetrachloroaurate (III) trihydrate as inorganic precursor. Thin films were deposited onto the glass substrates, at 450 oC by simple spray pyrolysis technique. The novel mesostructured tin oxide thin films with various Pt concentration exhibit highly selective response towards CO. The correlation of the Pt incorporation in the mesostructure with specific morphology and gas sensing behavior is discussed using scanning electron microscopy (SEM), X-ray diffraction (XRD), BET surface area, transmission electron microscopy (TEM) studies.

E-V.07 10:15 NANOSTRUCTURED MANGANESE FERRITE THIN FILMS FOR GAS SENSOR

APPLICATION I. Sandu, L. Presmanes, P. Alphonse, P. Tailhades, CIRIMAT – LCMIE, CNRS UMR 5085,

Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex, France Ferrite compounds are very important because of their optical, electrical or magnetic

properties. Moreover, many papers relate to their development as possible gas sensor. In this study, we were interested in using manganese ferrite as sensitive layer for CO2

sensor devices. Such an application required a high surface activity, and consequently a small crystallite size and a large surface area. The physical vapor deposition (RF-sputtering) is widely used for thin film synthesis. In this work, porous thin films were obtained from a Mn1.5Fe1.5O4 target sputtered under pure argon plasma, by optimizing the deposition parameters (gas pressure, power). The deposition time was adjusted in order to obtain an average thickness of 300 nm. Structural (G-XRD) and microstructural (SEM-FEG, gas adsorption, electron microprobe) analyses were carried out on these thin films. The chemical composition was found to be homogeneous on the whole surface of the samples. The grain size ranged from 15 to 25 nm. The surface enhancement factor (SEF) was about 100 m2/m2, which is equivalent to a specific surface area of 70 m2/g for the ferrite layer. In conclusion, these nanostructured manganese ferrite films appear to be quite suitable for an application as gas sensors.

10:30 BREAK

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Session VI : Functionalization Session chairs : Shinji Inagaki and Norikazu Nishiyama E-VI.01 11:00 -Invited- STRUCTURAL AND PHOTOCATALYTICAL PROPERTIES OF SELF-ASSEMBLED

ULTRATHIN FILMS PREPARED FROM INORGANIC/ORGANIC COLLOIDS I. Dékány, L. Korösi, R. Kun, T. Szabó, J. Ménesi and Sz. Papp, Department of Colloid

Chemistry and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi v.t.1.Hungary, 6720 Szeged, Hungary

The layer structured self-assambled materials can be used for the fixation of polymers or colloidal nanoparticles. They can adsorb on the surface of the glass support with their protecting layers allowing the preparation of semiconductor and noble metal nanocomposites by this method. These synthesis strategies were successfully applied for the preparation and intercalation of Pd, Ag metal and TiO2, ZnO and SnO2, semiconductor nanoparticles in layer-structured materials. The structural properties of these composites have been investigated by optical measurements (band-gap energies), X-ray diffraction, small angle X-ray scattering, atomic force and transmission electron microscopy.

Natural and synthetic layer structured materials (silicates, layer double hydroxides and graphite oxides) were used for stabilization of semiconductors by layer-by-layer methods. The nanoparticles of 2-5 nm diameter can be incorporated into the interlayer space of the support materials. The fluorescence properties of ZnO nanoparticles were also strongly influenced by structural and intercalation properties of nanoparticles. Pure hydrophobic graphite macrocrystal was converted to hydrophilic graphite oxide (GO) in strongly oxidizing medium. The degree of reduction of graphite oxide to nanostructured graphite influenced the optical and electrical properties of GO/ TiO2, and GO/ZnO multilayer films. Zn/Al layered double hydroxides (LDH) were prepared by sol-gel method and amorphous silica (SiO2) sol were used for the film deposition. For comparison the LBL films as catalyst and bulk suspensions were used to determine the differences between the preparation methods of catalysts in the photocatalytic efficiency studies.

E-VI.02 11:30 -Invited- MODIFIED MESOPOROUS THIN FILMS OF SiO2, TiO2 AND ZnO Jiri Rathousky, J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the

Czech Republic, Dolejskova 3, 18223 Prague 8, Czech Republic The application potential of mesoporous thin films and their significance for fundamental

physico-chemical studies can be substantially enhanced by their modification. The present communication is aimed at the preparation of mesoporous thin films of SiO2, TiO2 and ZnO, whose surface is modified by organic moieties. Special attention has been given to the achievement of optimum texture, as it often decisively influences the performance of the films in, e. g., photocatalysis and photoelectrochemistry.

The three-step preparation procedure comprises the synthesis of a mesophase by the sol-gel/dip-coating technique (SiO2, TiO2) or potentiostatic electrodeposition (ZnO) exploiting the ordering action of surfactant aggregates or dye molecules, the removal of the template and either direct introduction of dye molecules, or the surface functionalization followed by the immobilization of electroactive molecules. SiO2 films exhibit very narrow pore size distribution, the pore size typically decreasing due to the functionalization and anchorage of redox species via ionic or covalent bonds from 6 nm to 5 nm. As an example of covalent anchorage, ferrocenecarboxylic acid was linked to the aminofunctionalized silica film via peptide bonding. Their response is about four times higher comparing with a monolayer on the electrode. By covalent binding -Si(CH3)3 groups on the surface of mesoporous TiO2 films, substantial hydrophobicity has been achieved, leading to increased efficiency of the photocatalytic destruction of methylene blue and thionine. The readsorbed ZnO/eosine Y films display substantially developed mesoporosity in comparison with non-porous as-synthesized ones, resulting in a large improvement of the dye-sensitized photoelectrochemical performance.

E-VI.03 12:00 ORDERED MESOPOROUS ORGANOSILICA FILMS Muriel Matheron, Thierry Gacoin, Jean-Pierre Boilot, Groupe de Chimie du Solide,

Laboratoire de Physique de la Matière Condensée, UMR CNRS 7643, Ecole Polytechnique, 91128 Palaiseau, France, Alexis Bourgeois, Aline Brunet-Bruneau, Laboratoire d’Optique des Solides, UMR CNRS 7601, Université Paris VI, Campus Boucicaut, 140 rue de Lourmel, case 80, 75015 Paris, France, Pierre-Antoine Albouy, Laboratoire de Physique des Solides, Université Paris-Sud, 91405 Orsay Cedex, France

Ordered silica-based mesoporous films are well-known materials that may find applications in microelectronics and optics. They are often synthesized by the sol-gel process in the presence of surfactants. The TEOS-CTAB system leads to three periodic mesostructures (3D-hexagonal, cubic, 2D-hexagonal). The porous films contain mesopores and micropores, which are inside the polymeric silica clusters and hence in the walls separating the mesopores. Ellipsometric porosimetry experiments coupled to infrared ellipsometry showed that, in the 3D-hexagonal structure, the microporous volume fraction represents 1/3 of the total porosity.

One can take benefit from the large surface area of the mesoporous films to functionalize them. New properties may be induced, depending on the choice of the organic group. Furthermore, it is necessary to incorporate organic groups in order to stabilize the porous silica structure towards chemical contaminations from the environment. The functionalization of a mesoporous film may be achieved either by post-synthesis grafting or cocondensation of TEOS and a functionalized alkoxyde. Usually, the cocondensation leads to a loss of the periodic arrangement when the molar ratio of functionalized alkoxysilane/TEOS reaches 20-30%. Our work presents a new synthesis that allows to incorporate high loadings of organic groups into the mesoporous films without loss of long-range order. Periodic films can be prepared with a molar ratio of

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methyltriethoxysilane/TEOS of up to 1. Three different structures are formed, corresponding to the ones obtained with the TEOS-CTAB system. The evolution of the phase stability domains as a function of the nature and amount of methyltriethoxysilane is explained from the structure and reactivity of the hybrid silica clusters.

E-VI.04 12:15 ADSORPTION OF CATIONIC PORPHYRIN AND TRIS(2,2'-BIPYRIDINE)

RUTHENIUM(II) ONTO NANOPOROUS SILICAS Atsuko Yoshida(a), Minoru Somiya(a), Makoto Ogawa(a,b), (a)Graduate School of Science

and Engineering, Waseda University, Nishiwaseda 1-6-1, Shinjuku-ku, Tokyo 169-8050, Japan, (b)Department of Earth Sciences, Waseda University, Nishiwaseda 1-6-1, Shinjuku-ku, Tokyo 169-8050, Japan

Encapsulation of dyes into mesoporous silicas has been investigated to construct photofunctional supramolecular materials. Here the adsorption of cationic porphyrin and tris(2,2'-bipyridine)ruthenium(II) onto nanoporous silicas was reported. The adsorption of a cationic porphyrin, tetrakis-(N-methyl-4-pyridiniumyl)porphine, into nanoporous silica films and powders was investigated. The nanoporous silica films were prepared by rapid solvent evaporation method and the dye introduction into the films was conducted by the reaction using methanol solutions of tetrakis-(N-methyl-4-pyridiniumyl)porphine p-toluenensulfonate at room temperature. The cationic porphyrin was adsorbed effectively onto nanoporous silica films to give blown colored films. The absorption and luminescence spectra of the films and the effects of the external stimuli on them will be reported. The adsorption and immobilization of tris(2,2'-bipyridine)ruthenium(II) ([Ru(bpy)3]2+) in mesoporous silicas modified by the sulfonic acid groups was also investigated. The complex was immobilized by the cooperative effects of electrostatic interactions between [Ru(bpy)3]2+ cation and sulfonic acid group and the interactions with the phenyl rings of the mesopore surface and the bipyridine rings.

E-VI.05 12:30 SYNTHESIS AND CHARACTERIZATION OF TRANSITION METAL OXIDE DOPED

MESOSTRUCTURED SILICA FILMS R. Supplit, Institute of Materials Chemistry, Getreidemarkt 9/165, 1060 Vienna, Austria, N.

Hüsing, Division of Inorganic Chemistry I, University of Ulm, Albert-Einstein Allee 11, 89069 Ulm, Germany

Thin silica films doped with transition metal oxides (Ti, Fe, Hf) are of special interest for application such as sensors, membranes or catalysts. The focus of this work is on the preparation of mesostructured silica films doped with transition metal oxides relying on a combination of ligand-assisted templating and evaporation-induced self-assembly. By this approach, the surfactant not only serves as structure directing agent, but also acts as an agent to control and slow down the hydrolysis and condensation rate of the transition metal alkoxide and to position the latter at the template-silica interface to achieve high homogeneity and dispersion within the silica matrix.

The first step is the synthesis of a surfactant – metal alkoxide complex. Surfactants, such as poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) or polyether-based Brij-56, were reacted with titanium isopropoxide, hafnium ethoxide and iron ethoxide. By using these modified surfactants as templates, well ordered mesostructured silica/metal oxide films with high loading of the metal were prepared. The influences of a varying ratio of block copolymer to silica precursor and of a subsequent heat treatment on the mesostructure were studied by GI-SAXS, TEM, and N2-sorption techniques.

12:45 LUNCH

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Thursday, June 2, 2005 Afternoon Jeudi 2 juin 2005 Après-midi Session VII : Innovative Characterization methods Session chairs : Kuei-jung Chao and Pierre-Antoine Albouy E-VII.01 14:00 -Invited- X-RAY DIFFRACTION STUDY OF MESOSTRUCTURED THIN FILMS USING

ULTRA-THIN SUBSTRATES P-A. Albouy, Laboratoire de Physique des Solides, Bât.510, Université de Paris-Sud, 91405

Orsay, France An important drawback for the X-ray study of thin films is due to the opacity of the

deposition substrate that limits the accessible fraction of reciprocal space. This fraction is maximised using a grazing incidence geometry with incidence angle close to the substrate critical angle where the substrate background is reduced. However exploring higher incidences, up to normal incidence, may be necessary and remains forbidden. It is presently shown that ultra-thin silicon wafers (ca. 10µm thick) offer an interesting alternative. They present a high transparency to Cu-Kα photons and a low background contribution. A first "historical" example will be furnished by Langmuir-Blodgett films of a rigid rod polymer. Due to the sequential deposition process, it is normally assumed that L-B films present a layered structure. The substrate transparency allowed diffraction patterns to be taken from normal to grazing incidences demonstrating the existence of a purely nematic-like order without any layering. Further examples will concern mesoporous thin films. For instance, disordered silica-based mesoporous films deposited on similar substrates revealed diffraction ellipsoids instead of spheres: this was interpreted in terms of purely unidirectional (normal to the plane) lattice shrinkage occurring during solvent evaporation. More generally, it is shown that the use of ultra-thin substrates makes the conditions of grazing incidence much less stringent. In particular, the existence of in-plane diffraction spots that can be masked by the shadow of massive substrates, is easily and unambiguously revealed.

E-VII.02 14:30 -Invited- CHARACTERIZATION OF SIO2 MESOPOROUS FILM AND THE REDUCTION OF

ITS WATER UPTAKE Kuei-jung Chao, Kuo-ying Huang and Zhi-ping He, Department of chemistry, Tsinghua

University, Hsinchu, Taiwan Mesoporous silica films supported on glass and silica wafer substrates have been fabricated

by sol-gel coating method through P123 and Brij-56 surfactant templating synthesis, their calcined forms exhibit high porosity (~ 50%) and channel or interconnected pore structure of uniform pore size in the range of 2-7 nm. The resulting mesostructure and film texture are controlled by the specific chemical and processing parameters. Optical and electronic applications of these continuous thin films depend on their mesostructure and water up-take. The template-free mesoporous silicas are usually rich in surface silanol groups and thus adsorb water molecules easily. The hydrophilic mesoporous silica films have been modified to achieve an acceptable hydrophobicity through in-situ trimethylsilane silylation during the preparation of precursor sol and post-treatment with hexamethyldisilazane vapor. In this report, the properties of mesostructured films such as porosity, density and thickness as affected by environmental humidity or water uptake and silylation treatment are emphasized. The thermal stability of hydrophobicity and related reduction of water uptake are examined. These are investigated using X-ray diffraction, X-ray reflectivity, infrared and temperature- programmed desorption with mass spectroscopy. The detailed mechanism of hydrophobic modification of mesoporous silica is also studied by 29Si- and 13C-NMR.

E-VII.03 15:00 DETERMINATION OF POROUS PROPERTIES OF MESOPOROUS SILICA THIN

FILMS BY QUANTITATIVE X-RAY REFLECTIVITY ANALYSIS AND GISAXS S. Dourdain(a), A. Mehdi(b), J.F. Bardeau(a) and A. Gibaud(a), (a)Laboratoire de Physique

de l'Etat Condensé, UMR CNRS 6087, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans Cedex 09, France, (b)Laboratoire de Chimie Moléculaire et Organisation du Solide, UMR 5637 CNRS, Université de Montpellier II, Place E. Bataillon, 34095 Montpellier Cedex 5, France

Porosity and "specific surface" of mesoporous powders are usually obtained by BET measurements. In thin films this technique cannot be used because of the tiny quantity of matter they offer. We report a novel approach for determining the porous properties of the mesoporous silica thin films in which the surfactant was removed by washing. X-ray Reflectivity (XR) curves, analyzed above and below the critical angle of the substrate[1], are evaluated by suitable approaches to obtain the average electron density of the films, the wall thickness, the electron density of the walls, the radius of the pores and subsequently the meso and microporosity of such films. In combination with Grazing Incident Small Angle X-ray Scattering (GISAXS), the "specific surface" of the mesopores is ascertained, thereby for the first time providing a complete analysis of the porosity in thin films by x-ray scattering methods[2].

E-VII.04 15:15 POROSITY AND MECHANICAL PROPERTIES OF MESOPOROUS THIN FILMS

ASSESSED BY ELLIPSOMETRIC POROSIMETRY (EP) Cédric Boissiere(a), David Grosso(a), Lionel Nicole(a), Adrien Darragon(b), Clément

Sanchez(a), (a)Laboratoire de Chimie de la Matière Condensée, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 PARIS Cedex 5, France, (b)CTO SOPRA, 26 Rue Pierre Joigneaux, 92270 Bois Colombes, France

Accurate descriptions of ordered mesoporous structures made of pure and mixed metal-oxides thin films prepared by Evaporation Induced Self Assembly (EISA) with several types

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of structuring agents (CTAB or block copolymers F127 and/or KLE) were obtained by combining 2D-SAXS analysis, Ellipsometry and Ellipsometric-Porosimetry (EP) with water to produce adsorption-desorption isotherms. A specially designed experimental ellipsoporometer was used to allow rapid analysis of mesoporous structures at ambient pressure and temperature. Calculated via the modelisation of pore contraction during the removal of surfactants and a modified Kelvin equation, structural and mechanical properties were accurately measured and characteristic signatures of structures and compositions were evidenced.

E-VII.05 15:30 MECHANICAL PROPERTIES OF MESOPOROUS SILICA THIN FILM: EFFECT OF

SURFACTANT REMOVAL PROCESSES N. Chemin(a), M. Klotz(a), V. Rouessac(b), A. Ayral(b), E. Barthel(a), (a) Laboratoire

CNRS/Saint-Gobain “Surface du Verre et Interfaces”UMR 125, 39 quai Lucien Lefranc, BP 135, 93303 Aubervilliers Cedex, France, (b)Institut Européen des Membranes, UMR 5635, CNRS-ENSCM-UMII, CC047, Université Montpellier II, 34095 Montpellier Cedex 5, France

Mechanical properties including hardness and Young's modulus of ordered mesostructured silica thin films are characterized by nanoindentation measurements. PE6800 and CTAB are used as templating agents. Emphasis is given on the effect of template removal by thermal treatment, solvent extraction or UV-Ozone irradiation. The mechanical properties of the film are intimately correlated to the microstructure of the silica network and the film porosity, as studied by IR, X-ray diffraction, N2 adsorption and ellipsometry.

Particularly, the position and shape of the longitudinal optical vibration mode of the Si-O-Si asymmetric stretch are correlated to the mechanical response as a function of the treatments. We observe a contrasted behaviour between PE6800 and CTAB templated films. PE6800 templated films present low initial silica condensation state and high network contraction after post-synthesis treatment whereas CTAB templated films exhibit higher initial silica condensation degree and lower contraction after template removal. These behaviours are correlated to the strengthening of the silica structure and the decrease of the film porosity during template removal, which evolve differently according to the nature of the template and the template removal process.

E-VII.06 15:45 DEPENDENCE OF MOLECULE DIFFUSION WITH PORE SURFACE FEATURES IN

MESOPOROUS FUNCTIONALISED THIN FILMS ASSESSED BY ELECTROCHEMICAL TOOLS

E. Otal(a), P.C. Angelomé(b), S. Aldabe-Bilmes(a) and G.J.A.A. Soler-Illia(b), (a)DQIAyQF and INQUIMAE, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, C1428 EHA, Buenos Aires, Argentina, (b)Unidad de Actividad Química, Comisión Nacional de Energía Atómica, CAC, Av. Gral Paz 1499, B1650KNA, San Martín, Buenos Aires, Argentina

Mesoporous functionalised thin films are highly interesting for applications ranging from sensors to tailored sorbents to bioactive nanocomposites. A fundamental issue is the accessibility and transport of molecules (analytes, reaction products, biomolecules...) within the pore system, and the role of the pore surface modification in the controlled behaviour of the cavity. Electrochemical methods afford the possibility to evaluate pore accessibility and exposed area to electroactive probes.

Mesoporous thin MO2 films (M=Si, Ti, Zr, Si/Ti...) with organic functions (phenyl, polyol, alkyl...) are deposited on conducting substrates (Pt, ITO) by dip-coating, using block copolymer templates. Organic functions are added by post-grafting (using silane or phosphate anchoring groups) after template removal, leading to modified mesoporous electrodes. Film features (eg. exposed substrate area) and properties can be readily evaluated by using electrochemical techniques coupled with spectroscopy. The diffusion of electrochemical probes with different size and polarity (eg. H+, ferrocyanide, ferrocene derivatives, viologen...) was evaluated by cyclic voltammetry. Diffusion values for redox probes in modified MO2 are drastically affected by changing the function size or polarity. All the studied systems present ip = v1/2. While relatively small modifiers (phenyl, glycerol) partially block the pore system, the use of longer chains or bilayers (dodecylphosphate) completely hinders probe diffusion.

16:00 BREAK

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Session VIII : Environmental and analytical applications: membrane separation, catalysis, sensors Session chairs : Peter Alberius and Mihail Barboiu E-VIII.01 16:30 -Invited- FROM MOLECULAR INFORMATION TO HYBRID MEMBRANES, AS TOOLS FOR

INFORMATION TRANSFER DEVICES Mihail Barboiu, Institut Européen des Membranes, Montpellier, France The chemistry of membrane transport systems of interest for molecular information transfer

has been extensively developed during the last twenty years. The membrane selectivity may be induced either by carrier molecules or by transmembrane channels. Looking to the important amount of the papers concerning the transport mechanism in membranes the concept of carrier was every time associated with liquid membranes and the term of channel with bilayers membranes. From the mechanistic point of view, we use carriers which self-assemble in functional aggregates which would present combined (hybrid) intermediate features between the former carrier-monomers and the resulted pseudo-channel-forming structures. Thus, we therefore studied the membrane transport properties in solid heteropolysiloxane materials of such supra-molecular and organic-inorganic hybrid polymers resulted by the dynamic self-assembly of the hydrogen-bonded functional receptors. Individual and collective transport properties of such supramolecular hybrid assemblies have been emphasized.

1.Barboiu, M.; Guizard, C.; Hovnanian, N.; Palmeri, J.; Reibel, C.; Luca, C.; Cot, L. J. Membrane Sci. 2000, 172, 91-103. 2.Barboiu, M.; Guizard, C.; Hovnanian, N.; Cot, L. Sep. Tech. Pur., 2001, 25, 211-218. 3.Barboiu, M.; Vaughan, G.; van der Lee A., Org. Lett., 2003, 5 (17), 3073-3076. 4.Barboiu, M., J. Incl. Phenom. Mol Rec. 2004, 49, 133-137. 5.Barboiu, M.; Cerneaux, S.; Vaughan, G.; van der Lee, A.. J. Am. Chem. Soc., 2004, 126, 3545-3550.

E-VIII.02 17:00 STUDIES ON FORMATION OF SUPPORTED LIPID BILAYERS CLOSE TO THE

PHASE TRANSITION TEMPERATURE B. Seantier(a), C. Breffa(a), O. Félix(a) and G. Decher(a,b), (a)Institut Charles Sadron

(CNRS, UPR 22), 6 rue Boussingault 67083 Strasbourg Cedex, France, (b)Université Louis Pasteur, 4 rue Blaise Pascal 67000 Strasbourg, France

E-VIII.03 17:15 CORRELATIONS BETWEEN DIP COATING-FABRICATED CELLULOSE ACETATE

MEMBRANES CHARACTERISTICS AND THEIR PERMEABILITY TO GLUCOSE AND GLUCOSE OXIDASE MEMBRANES

L. Setti, A. Fraleoni-Morgera, A. Filippini, D. Frascaro, Dept. of Industrial and Materials Chemistry, Univ. of Bologna, V. Risorgimento 4, 40136 Bologna, Italy

E-VIII.04 17:30 ANATASE-BASED MESOSTRUCTURED THIN FILMS AND MEMBRANES Florence Bosc(a),André Ayral(b) and Christian Guizard(b), (a)Laboratoire des Matériaux,

Surface et Procédés pour la Catalyse, UMR n°7515 CNRS-ECPM-UPL, Strasbourg, France, (b)Institut Européen des Membranes, UMR n°5635 CNRS-ENSCM-UMII, Montpellier, France

E-VIII.05 17:45 CATALYTIC COATINGS ON STAINLESS STEEL PREPARED BY SOL-GEL ROUTE Dimitri Truyen, Matthieu Courty, Pierre Alphonse, Florence Ansart CIRIMAT, UMR-

CNRS 5085, Paul Sabatier University, 118 route de Narbonne, 31062 Toulouse Cedex 04, France

E-VIII.06 18:00 PROCESSING AND STRUCTURAL CHARACTERIZATION OF POROUS

REFORMING CATALYST FILMS Xianghui Hou, Jey Williams, Kwang-Leong Choy, School of Mechanical, Materials and

Manufacturing Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, U.K.

18:15-20:00 POSTER SESSION II

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POSTER SESSION II Thursday, June 2, 2005

18:15 – 20:00

Session chairs : Eduardo Ruiz Hitzky and André Ayral E/PII.01 EFFECTS OF NiO/TiO2 ADDITION IN ZnFe2O4 – BASED GAS SENSORS IN THE FORM OF POLYMER

THICK FILMS K. Arshak and I. Gaidan, Microelectronic and semiconductor Research Group, ECE Department, University of

Limerick, Plassey Technological Park, Limerick, Ireland Zinc ferrite (ZnFe2O4) was prepared in accordance with reference [1]. A combination of ZnFe2O4, nickel oxide

(NiO) and titanium dioxide (TiO2) powders were used to fabricate a novel thick film gas sensor. NiO and TiO2 powders were added to improve the grain size, which results in the increased gas sensitivity. The smaller the grain size, the larger the specific surface area, which results in greater oxygen adsorption and higher sensitivities, and vice versa [2]. The sensor was connected with three resistors to form a bridge circuit. After balancing, this arrangement was used to detect butanol and pentanol at a concentration range of 0-1000 ppm and hexanol in 0-250 ppm range. It was found that the change in bridge output voltage, ∆V = Vgas-V0 increases linearly with increasing the concentration of gas vapour. The sensitivity was calculated as the slope of the graph (bridge output voltage (mV) versus gas concentration {ppm}). The sensitivity of the sensor to butanol, pentanol and hexanol were: 0. 096, 0.106 and 0.8 mV/ppm respectively. The response/recovery times are defined as the times required to reach 90% of response/recovery when the gas is turned on or off respectively and they were: 60/120 sec, 120/180 sec, and 150/220 sec, for butanol, pentanol and hexanol respectively.

[1] K. Arshak, I.Gaidan, L. Cavanagh (IMAPS), International symposium on microelectronics Conference, 2003. [2] J.Xu, Q pan, Y. Shun, Z. Tian "Grain size control and gas sensing properties of ZnO gas sensor " Journal of Sensors and Actuators B, Vol, 66, pp, 277-279, 2000.

E/PII.02 PREPARATION, CHARACTERIZATION AND DEPOSITION OF LANGMUIR-BLODGETT Co, Al

ORGANIC FILMS FOR THE CATALYTIC APPLICATIONS J. Lojewska(a), A. Kolodziej(b), P. Dynarowicz-Latka(a), (a)Faculty of Chemistry, Jagiellonian University,

Ingardena 3, 30060 Kraków, Poland (b)Institute of Chemical Engineering PAS, Baltycka 5, 44100 Gliwice, Poland

Volatile organic compounds combustion is a demanding process for both reactor and catalyst design. One of the major problems is diffusional limitation of the reaction rate. As we have proved before, this may be overcome by designing the reactor metallic microstructure. Application of metallic carriers on industrial scale depends on the development of an efficient method of catalyst layering on the mesoscopic level.

In this study, the Langmuir-Blodgett (LB) method to deposit various metals in form of catalyst organic precursors was proposed. The film forming abilities of the precursors were checked by BAM and by monolayers stability measurements. The amount of deposited materials was controlled by the LB transfer parameters. The materials obtained were characterized at various stages of the preparation by SEM/EDX, XPS, RM methods and tested in n-hexane combustion. Catalyst activation by oxidation of organic groups led to the formation of highly dispersed metal oxides (Al2O3, Co3O4 spinel). Low-loaded cobalt catalysts obtained were active in combustion showing resistance to sintering. Compared to standard Pt supported catalyst it had twice as low activation energy(50 kJ/mol).

E/PII.03 THIN ORGANIC LAYERS PREPARED BY MAPLE AND GAS SENSOR APPLICATION R. Frycek, P. Fitl, V. Myslík, M. Vrnata, Department of Solid-State Engineering, Institute of Chemical

Technology Prague, Technická 6, 166 28 Prague 6, Czech Republic, M. Jelínek, T. Kocourek, The Academy of Sciences of the Czech Republic, Institute of Physics, Na Slovance 2, 18000 Prague 8, Czech Republic

It was shown that organic materials can be used as an active layer for conductivity gas sensors. It was found that Pulse Laser Deposition (PLD) is convenient technology for producing thin layers (from nanometer to micrometers). Metal Acetylacetonates (MAcAc) exhibit high sensitivity to oxidizing gases as well as reducing atmospheres. New technology -MAPLE - Matrix Assisted Pulse Laser Deposition has been developed for deposition of thin films from large organic molecules (up to several hundreds of amu). Starting material is embedded in frozen matrix which plays important role during energy transfer while laser pulse hits the target.

First experiments have been done with Indium(III) acetylacetonate, Tin(IV) bis(acetylacetonate) dichloride and Nickel(II) phthalocyanine. To certify successful transfer of original material FTIR and Raman spectroscopy have been used. Chemical sensors with those layers were tested at different atmospheres and temperature dependent sensitivity was acquired. Results from AC and DC measurements show that MAPLE technology is very perspective for preparation of high demand chemical sensors.

E/PII.04 COMPUTER- AIDED ANALYTE-RECEPTOR INTERACTION FOR SENSOR DESIGN C. Berlic, Ioan Stamatin University of Bucharest, Faculty of Physics, MG-11, 077125 Bucharest-Magurele,

Romania The fundamental understanding of the interaction between analytes and receptor surface in sensing chain system is

crucial in order to guide the design the appropriate materials of sensor devices. The interaction analyte-receptor rise to a signal, which amplified and correlated with analyte concentration give the sensibility and performances of any sen-sor usually composed of a chemical sensing system and a pattern-recognition system, such as an artificial neural network. Each analyte vapor presented to the sensing system produces a signature or "fingerprint". Our goal is to develop computational approaches to facilitate the design of polymer-receptor interaction with analytes. Two approaches are taking in account. The first is a lattice embedded with conducting polymer chains over percolation threshold and analyte molecules modify electrical conduction (am-perometric- potentiometer sensor). The second the lattice is embedded with a polymer-chromophor pendant group and analyte molecules induce an amplified fluorescence (smell -sensor). The simulation on simplified models shown the sensor response depend of characteristic times determined by diffusion -interaction processes and polymer con-figuration on lattice.

E/PII.05 PHOTOCATALYTIC PROPERTIES AND PHOTOCONDUCTIVITY OF HIGH SURFACE AREA

PHOSPHATED TITANIA FILMS László Korösi(a), Szilvia Papp(a), Vera Meynen(b), Imre Dékány(a,c), (a)Nanostructured Materials Research

Group of the Hungarian Academy of Sciences, University of Szeged, Aradi v. t. 1, 6720 Szeged, Hungary,

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(b)Department of Chemistry, Laboratory of Adsorption and Catalysis, University of Antwerpen, Drie Eiken Campus, Universiteitsplein 1, 2610 Wilrijk, Belgium, (c)Department of Colloid Chemistry, University of Szeged, Aradi v. t. 1, 6720 Szeged, Hungary

A series of high surface area phosphated titania samples (P-TiO2) with various amounts of phosphate have been prepared by a sol-gel technique. The structural characterization of the samples included X-ray powder diffraction (XRD), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, diffuse reflectance spectroscopy (UV-VIS-DR) and nitrogen adsorption measurements. The results of XRD and N2 adsorption measurements indicated that the structure of P-TiO2 depends on the phosphate content and the calcination temperature. XRD patterns revealed the stabilization of the anatase phase of TiO2 up to 900 °C in the presence of phosphate. The surface area of P-TiO2 increased with increasing phosphate content. The optical properties of these samples were investigated by UV-VIS-DR measurements and band gap energies were calculated.

The photocatalytic activity of P-TiO2 was studied in the liquid phase degradation of phenol. The rate of degradation by the catalyst was found to be improved at 1 mol% phosphate content. Any further increase of the phosphate concentration decreased the efficiency of the catalyst. The photoconductivity of P-TiO2 films depends on the phosphate content and calcinations temperature.

E/PII.06 INVESTIGATION OF PROPERTIES OF THIN SnOx FILMS ANNEALED IN VARIOUS ATMOSPHERES V.A. Botvin, K.A. Mit, D.M. Mukhamedshina, Institute of Physics and Technology, Almaty, Republic of

Kazakhstan Various specific and unique properties of SnO2 make the material useful for many applications. It is often applied

to fabricate the transparent conductive coatings for solar cells and opto-electric devices. The gas sensitive layers of SnO2 are widely used in making sensors for control of poisonous and combustible gas leakage.

In this work an influence of heat treatments of SnOx films in hydrogen gas, vacuum and air on optical and electrical properties are studied. The films were prepared by magnetron sputtering. The observed dependence of the refractive index of SnOx films from the atmosphere composition permits to make the conclusions about dynamics of processes related with the film structure. From the transmission spectra the optical parameters of films have been determined, and their density and porosity are evaluated as well. Correlation between the measured values of gas sensitivity and porosity is observed.

E/PII.07 CHARACTERIZATION AND PHOTOCATALYTICAL APPLICATION OF TiO2/SiO2 AND ZINC-

ALUMINUM LAYER DOUBLE HYDROXIDE MULTILAYERED FILMS PREPARED BY LBL IMMERSION METHOD

Robert Kun and Imre Dékány Department of Colloid Chemistry and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1., 6720 Szeged, Hungary

Multilayered self-assembled films from colloidal particles with constant or variable surface charge were prepared on the surface of glass plates using the “layer by layer” (LBL) immersion technique. As spherical particles with variable surface charge, TiO2 photocatalysts and silica sol particles were used for the preparation of multilayered, up to 20-layer films. Lamellar particles of zinc-aluminum layer double hydroxide with constant surface charge was a suspension (ZnAl-LDH), which were deposited on the surface of glass plates using the LBL dipping technique also. The multilayer preparation was monitored by absorbance measurements at a wavelength of l = 500 nm. The ZnAl-LDH layers were also controlled by XRD measurements. The thicknesses of the films were determined by ellipsometry measurements. The values were found to vary between 40 – 100 nm in the case of TiO2 and 150 – 1000 nm in the case of ZnAl-LDH.

Both TiO2 or TiO2/SiO2 multilayered films and ZnAl-LDH multilayered films were shown the destruction of acridine orange dye via photooxidation. In the photocatalytic experiments a photoreactor equipped with a 400 W high-pressure mercury lamp was applied. The emitted UV-photons below 320 nm were cut off using glass reaction vessel. UV-VIS spectroscopy was applied for the quantitative analysis of the organic dye molecule. The photocatalytic efficiency of the new photocatalyst ZnAl-LDH is close to the well-known P25 Degussa titanium dioxide.

E/PII.08 PHOTOCATALYTIC PROPERTIES OF PTHALOCYANINES ON TIO2 THIN FILMS M. Drobek(a), T. Strasak(a), P. Kluson(a), M. Karaskova(b) and J. Rakusan(b), (a)Institute of Chemical

Technology – ICT Prague, Faculty of Chemical Technology, Technicka 5, 166 28 Prague, Czech Republic, (b)Research Institute of Organic Syntheses 532 18 Pardubice-Rybitvi, Czech Republic

There is a gap between progress in fundamental research of photoactive functional nanoparticles and industrial demands for cheep, active coatings "working" with visible light. Central to this point is the search for an effective sensitizing molecule and for a suitable method of its surface deposition. Photodegradation of organics using dye-sensitized thin layers of TiO2 (titania) is an attractive process highly perspective for industrial use. Activation of TiO2 for the visible region is e.g. possible with phthalocyanine kind of compounds absorbing photons in the range from 400 to 800 nm. In this work we report on the role of metal phthalocyanines - namely Al and Zn, deposited on TiO2 thin films. Various deposition techniques are compared in terms of the physical and chemical properties of the sensitized thin layers. Activity tests of the produced sensitized layers have been conducted in a model photooxidation of acetone in gas phase.

E/PII.09 DEVELOPMENT OF ORIENTED NANOPOROUS THIN FILMS AND MEMBRANES S. Suzuki, Y. Yoshino, H. Taguchi and B.N. Nair, R&D Center, Noritake Company LTD., Aichi, Japan Thin films and porous membranes with oriented microstructure could offer great technological benefits in

catalysis, separation, fuel cells, microelectronics and bio-chemical applications. Under usual film forming conditions orientation of particles and pores is very difficult to attain. In this presentation, we show that thin films and porous membranes with very good orientation of structure could be produced by pulsed laser deposition technique. A homogenous microstructure made of uniform nano-particles and uniform nano-channels extending through the thickness of the membrane could be made by the method. Membranes with an oriented pore structure are very helpful due to the low tortuosity of such pores. This will greatly reduce the diffusion distance of permeating particles and molecules and therefore will enhance the permeability of the membrane. Moreover, in advanced membrane and electrolyte processing methods such as pore filling method the availability of oriented substrate microstructure will significantly improve the processability as well as reduce the practical electrolyte thickness. Functionalization of the pores could also lead to advancements in medical and bio-chemical applications.

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E/PII.10 FORMULATION OF A THIN CATALYTIC MEMBRANE LAYER FOR OZONOLYSIS OF ORGANIC WATER POLLUTANTS

Samuel Heng(a,b,c), Antoine Godde(b), King Lung Yeung(b), Anne Julbe(c), Jean-Christophe Schrotter(d), (a)Environmental Engineering Program and (b)Department of Chemical Engineering, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, (c)European Institute of Membranes, Place E. Bataillon, 34095 Montpellier Cedex, France, (d)Anjou Recherche, Veolia Water Research Center, Chemin de la Digue, BP 76, 78603 Maisons-Laffitte Cedex, France

Ozone is a strong oxidizing agent that has been widely used in disinfection and for color and taste removal in water and wastewater treatments. However ozonolysis reaction rate is slow and does not necessary lead to total mineralization of the organic pollutants. Therefore, this research targets the development of a catalytic membrane reactor that can significantly improve ozonolysis yield for biorefractory organic pollutants. This task requires the formulation of an active catalyst and casting material into a suitable membrane for the application. The ?-Al2O3 supported metals and metal-oxides are common catalysts used in ozonolysis of organic pollutants. Also, ?-Al2O3 is a common material for ceramic micro- and ultra-filtration membranes.

The catalytic activity of ?-Al2O3, TiO2/?-Al2O3 and Cu/ ?-Al2O3 were tested for catalytic ozonolysis of phenol. The phenol concentration was monitored with UV-Vis spectrometer and the organic content of the solution was measured from its total organic carbon (TOC). Both qualitative and quantitative analyses of adsorbed species on the catalysts were carried out using infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). These measurements provide an exact accounting of the carbon in both liquid and solid phases. Results showed that phenol conversion is not affected by the addition of ?-Al2O3 and there is no phenol adsorption on the ?-Al2O3. The TOC however showed a significant drop when ?-Al2O3 was added, mostly due to the adsorption of the carboxylic byproducts. A plot of the TOC degradation as a function of time indicated that there is no significant difference in the activity of TiO2/?-Al2O3 catalyst and ?-Al2O3. Better TOC degradation is obtained using a Cu/?-Al2O3 catalyst.

These results strongly suggest that for phenol ozonolysis, the ?-Al2O3 can be employed as either a membrane separator or contactor. As a membrane contactor, the adsorption of byproducts on ?-Al2O3 traps the organic species within the reaction zone for a longer time leading to their eventual mineralization. The selective removal of the less refractory ozone byproduct through a membrane could also significantly improve the treatment performance.

E/PII.11 ENCAPSULATION OF ENZYMES IN ALUMINA MEMBRANES OF CONTROLLED PORE SIZE M. Darder, P. Aranda, E. Manova, E. Ruiz-Hitzky, Instituto de Ciencia de Materiales de Madrid, CSIC,

Cantoblanco, 28049-Madrid, Spain; and M. Hernández-Vélez, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain

Controlled anodization of aluminium foils in different experimental conditions results in nanoporous alumina membranes with cylindrical pores of uniform diameter (from 200 to 20 nm) and length, in which is also possible to control the pore wall size. One interesting point is to have the possibility to design membranes with variable characteristics in order to prepare nanostructured materials for different applications. For instance, the encapsulation of bioactive species in home-made membranes of controlled dimensions has been tested in order to build electrochemical biosensors. Glucose oxidase (GOx) has been successfully immobilized in a set of membranes of different thickness and pore size. The porous structure in the thin film provides a high surface area, leading to the retention of a higher amount of enzyme.

Calibration curves, representing the anodic current vs. glucose concentration, were obtained for the prepared biosensors. The Michaelis-Menten constant values indicate that the response of biosensors based on membranes with the same thickness is slower as the pore diameter decreases, being also slower as the thickness increases and the pore size is kept constant. In these last cases, the biosensor response is linear in a wider concentration range for thicker membranes, although the glucose degradation kinetics is retarded. Thus, the control of membrane dimensions, pore diameter and thickness, is a key factor in the performance of these GOx/thin film-based biosensors.

E/PII.12 PHOTOCATALYTIC ACTIVITIES OF TiO2 THIN FILMS PRODUCED BY SURFACTANT-ASSISTED SOL-

GEL PROCESSING Urh Černigoj(a), Urška Lavrenčič Štangar(a), Polonca Trebše(a) and Dušan Strmčnik(b), Milena Zorko(b),

(a)Laboratory for Environmental Research, Nova Gorica Polytechnic, P.O.B. 301, 5001 Nova Gorica, Slovenia, (b)National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia TiO2 thin films were prepared from a titanium isopropoxide precursor by sol-gel processing in the presence or absence of various nonionic surfactant molecules (Brij 56, Triton X-100 or Pluronic F-127). The efficiency of the transparent films obtained by a dip-coating technique depended strongly on the use of and type of surfactant added. Titania/Pluronic sols resulted in homogeneous and crack-free TiO2 anatase films with a thickness of as much as 300 nm after one dipping and heat-treatment (500oC) cycle. Their morphology and mesostructure were characterized by microscopic techniques (SEM, AFM) and correlated with their photocatalytic and adsorption properties. To enhance the photocatalytic activity of the films SiO2 protective layer was deposited on the glass substrate prior to the deposition of the titania film. A monoazo dye Plasmocorinth B was chosen as a model compound for photodegradation studies as it is stable under environmental conditions and its degradation products are not coloured. The titania film was immersed in an aqueous solution of the dye, which was purged with oxygen and irradiated using a 125 W Xe lamp (with wavelenghts below 335 nm cut off). Changes in the absorption of the solution at 527 nm were monitored on-line as a function of irradiation time. A special continuous-flow reactor was designed for this purpose. All photodecolorisation curves indicate first-order kinetics. The highest photodegradation rate constant (2.1×10-4 s-1) was found for the films deposited from the sol with addition of the Pluronic surfactant and was almost twice higher than for films deposited from sols without the surfactant (1.1×10-4 s-1).

E/PII.13 EPOXY POLYMER SURFACE MODIFICATION THROUGH WET-CHEMICAL ORGANIC SURFACE

SYNTHESIS FOR ADHESION IMPROVEMENT IN MICROELECTRONICS S. Siau, A. Vervaet and A. Van Calster, ELIS-TFCG microsystems, Universiteit Gent, Sint-Pietersnieuwstraat 41,

9000 Gent, Belgium, Etienne Schacht, Polymer materials, Universiteit Gent, Krijgslaan 281, 9000 Gent, Belgium and Ulric Demeter, Solid state sciences, Universiteit Gent, Krijgslaan 281, 9000 Gent, Belgium

Wet-chemical surface synthesis reactions were performed on thin epoxy layers for usage as a build-up layer in microelectronics. The synthesis reactions, based on heterocyclic organic coupling agents, were used to imprint iminodiacetic acid and imidazole groups at the surface of the epoxy polymer, based on nucleofilic substitution reactions. The synthesized surfaces are examined by means of XPS and ATR-IR measurements. XPS

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measurements illustrate that the identity of the chemical groups near the interface (top 10 nm of the polymer surface) has been altered by the procedure. After the synthesizing procedure, copper was electrochemically deposited using an electroless/electroplating scheme. The type of groups located at the surface of the polymer has a pronounced influence on the adhesion strength of electrochemically deposited copper. Hence the interface between the copper and epoxy determines the adhesion properties between both. The surfaces of the peeled polymer layers and the backs of the copper strips were examined by XPS after the peeling procedure in order to determine the interface failure mechanism.

E/PII.14 AMBIPOLAR PENTACENE FIELD EFFECT TRANSISTORS BY ELECTRONIC INTERFACE

MODIFICATION Roland Schmehel, Marcus Ahles, Heinz von Seggern, Darmstadt University of Technology, Material- and Geo-

Science Department, Germany Pentacene is well known as an interesting organic semiconductor for p-channel field effect transistors. However,

the realization of an n-channel transistor based on pentacene usually failed. In this study, deep electron traps were detected at the Pentacene/SiO2 interface by means of capacitance measurements. These electron traps are suspected as origin for the missing electron mobility for n-channel transport. Therefore Ca has been introduced at the gate oxide in order to fill these electron traps by electron donation. This doping allows for an n-channel operation. In order to demonstrate the ambipolar character of pentacene, an ambipolar transistor with top-gold and top-calcium contacts is realized by shadow mask evaporation techniques. By means of an equivalent circuit model based on a resistor-capacitor network the basic electrical properties of the transistor are determined. The model yields comparable hole and electron mobilites in the order of 0.1 cm2/Vs. It is further shown that the insertion of a thin PMMA-layer between pentacene and SiO2 reduces the electron trap density significantly, which indicates that the origin for the electron traps is probably related to SiO2.

E/PII.15 PHASE TRANSITION AND LUMINESCENCE PROPERTIES FROM VAPOR ETCHED SILICON S. Aouida, M. Saadoun, K. Ben Saad, B. Bessaïs Institut National de Recherche Scientifique et Technique,

Laboratoire de Photovoltaïque et des Semiconducteurs, BP 95, 2050 Hammam-Lif, Tunisie In this work, we propose to present the structure and photoluminescence (PL) properties, under different excitation

sources, of a white powder-like ammonium hexafluorosilicate (NH4)2SiF6) obtained from HF/HNO3 chemical vapor etching (CVE) of silicon wafers [1]. The CVE method leads either to the formation of luminescent Porous Silicon (PS) or to the (NH4)2SiF6) depending on the experimental conditions. It was found that the CVE technique can generate, at specific conditions (i.e., HF/HNO3 volume ratio > 1/4), the (NH4)2SiF6 phase instead of PS. The (NH4)2SiF6 marketed powder is not luminescent, while that obtained from silicon vapor-etching presents a noticeable intense and stable photoluminescence (PL) having two shoulders. Two processes have been proposed to explain this PL property. First, the powder was found to contain silicon nanoparticles, which contribute efficiently to visible luminescence at the low energy side. Second, the formation of SiOx features around the silicon nanoparticles lead to oxide related states that may trap electrons or excitons, depending on the silicon nanopraticle size [2], from which radiative recombination leads to a specific PL shoulder at higher energy.

[1] M. Saadoun, N. Mliki, H. Kaabi, K. Daoudi, B. Bessaïs, H. Ezzaouia, R. Bennaceur, Thin Solid Films 405 (2002) 340. [2] M. V. Wolkin, J. Jorne, P. M. Fauchet, G. Allan, C. Delerue, Phys. Rev. Lett.82 (1999) 197.

E/PII.16 NOVEL DEVICE APPLICATIONS OF THIN SELF-SUPPORTED LAYERS E.D. Gu, J. Zhou and M. Wu, State key laboratory of advanced technology for materials synthesis and processing,

Wuhan University of Technology, Wuhan 430070, P.R. China Due to their unique physical properties such as high transmissibility and low thermal conductance, thin and ultra-

thin self-supported layers with thicknesses ranging from a few ten to a few hundred nanometers play an increasingly important role in novel device developments and applications. Special device functionalities and superior performances can be achieved by integrating devices with such thin self-supported layers. In this paper, we report the fabrication of both epitaxial and amorphous thin self-supported layers and the integration of these layers with magnetic and temperature sensor devices. Thin and ultra-thin self-supported layers were formed by layer growth and then dry reactive ion etching or wet chemical etching. In order to integrate the self-supported thin layers with the delicate devices which are incompatible with the etching process, novel techniques for fabricating integrated devices have been developed. We demonstrate that thin and ultra-thin self-supported layers up to several millimeters in size can be successfully fabricated and integrated with the devices. These thin self-supported layers and devices fabricated on them have been characterized. The performances of the devices were also measured.

E/PII.17 DOSE DEPENDENCES OF THE OPTICAL PROPERTIES OF FULLERENE FILMS UNDER ELECTRON

IRRADIATION I.P. Dmytrenko, N.P. Eulish, N.I. Belyi and Yu.I. Prylutskyy, Kyiv National Shevchenko University, Department

of Physics and Biophysics, Volodymyrska Str., 64, 01033 Kyiv, Ukraine; V.V. Shlapatskaya, Institute of Physical Chemistry of NAS of Ukraine, pr. Nauky, 31, 03028 Kyiv, Ukraine; H. Bernas, CNRS-UMR 8609, University Paris XI, France; P. Scharff, Technical University of Ilmenau, Institute of Physics, 98684 Ilmenau, Germany

The studies of optical properties and crystal structure of the solid C60 and C70 films under the electron irradiation (Ее=1,8 MeV) in the range of dose loads from 0,5 to 4 MGy show that the radiation displacement of carbon atoms from the shells of molecules and their introduction into the interstitial positions of crystal lattices of condensed C60 and C70 takes place. Moreover, the appearance of additional intermolecular interaction in this case affects on the lattice parameters, the radiant emittance of the excitons, occupied by the X-centers, the electron spectra of molecules in the region of inter-zone transitions, and also the behavior of vibrational Ag and Hg modes. The further growth of radiation dose to 10 MGy leads to the increase of the content of the polymerized phase and to the essential radiation distortions of the fullerene molecules, that is manifested on the crystal structure and the optical properties. It is important to note that with an increase in the radiation dose the relaxation of the above properties for the C70 molecules is observed, that is absent for the C60 fullerenes. This work is supported by the “Dnipro” Program.

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E/PII.18 EVAPORATED THIACALIX[4]ARENE FILM ON SEMICONDUCTORS SUBSTRATES AS COPPER ION SENSING

M. Ben Ali(a,b), M.ALI MAAREF(b), C.Martelet(c), N. Jaffrezic-Renault(c), (a)Institut Supérieur des Sciences, Appliquées et de Technologies, Cité Taffela–Ebn Kaldoun, 4003 Tunisia, (b)Laboratoire de physique de semi-conducteurs et Capteurs, IPEST la Marssa, 2070 Tunis, Tunisia, (c)ICEGELY, Ecole Centrale de Lyon, Avenue Guy de Collongue, 69134 Ecully Cédex, France

Thin thiacalix[4]arene (TCA)film was deposited using the technique of thermal evaporation under vacuum to fabricate chemical on EIS micosensors. Electrochemical measurements were made to study the sensitivity and selectivity of thiacalix[4]arene based sensors towards cooper metal ions.

The sensitivity of the sensor depend of the thickens of the sensitive layer. Only a weak response of 18 mV/decade was observed with a thiknes of 100nm of TCA layer. However, a Nernestian response ( about 30 mV/decade) was obtained using a thin films of thiacalix[4]arene 20 nm. This results can be explained by the orientation of thiacalix[4]arene molecules in evaporation process. For 100 nm films of thiacalix[4]arene, the deposition process depend of the interaction between TCA-TCA. Wheras, for the thin films(20 nm), the surface of the oxyde substrate can interact with TCA molecules and controlled their orientation that make easy the diffusion of the copper ions to the cavities of thiacalix[4]arene molecules and can contribute to improve the sensibility of the sensor.

E/PII.19 OPTICAL PROPERTIES OF CADMIUM SELENIDE HETEROSTRUCTURES WITH QUANTUM-SCALE

SURFACE FORMATIONS V.P. Makhniy, M.V. Demych, M.M. Slyotov, P.P. Horley, V.V. Gorley, Chernivtsi National University, 2

Kotsyubynsky Str., 58012 Chernivtsi, Ukraine, and Yu.V. Vorobiev, J. Gonzalez-Hernandez, CINVESTAV Unidad Queretaro, Libramiento Norponiente 2000, Fracc. Real de Juriquilla, 76230 Queretaro, QRO, Mexico

Isovalent replacement method was used to obtain heterolayers of alpha- and beta-CdSe with high structure perfection, deposited on scintillator CdS<Te> and ZnSe<Te> crystals. Resulted monolith device has good properties for ionizing radiation detector applications. Our preliminary investigations showed the possibility to control device properties by depositing a quantum-scale formations over its surface, which also leads to overall device efficiency be improvement. This paper is dedicated to investigation of surface quantum-scale structure influence on optical characteristics of CdSe heterolayers. Structure modification was carried out by annealing process using technology developed by the authors. It was shown, that the device with modified surface feature significant increase of edge luminescence, shifting of transmission edge towards long-wave region and appearance of spectral lines corresponding to the energies higher than CdSe bandgap. Observed characteristics of high-energy luminescence band depending on excitation level, time, temperature, as well as the shift of transmission edge were explained in the frame of quantum-scale effect theory.

E/PII.20 PROCESSING AND CHARACTERIZATION OF HIGH DISPLACEMENT MONOLITHIC PIEZOELECTRIC

ACTUATOR Jong-Hoo Paik, Sei-Ki Kim, Mi-Jae Lee, Byung-Hyun Choi, Eun-Kyeong Lim, Korea Institute Ceramic

Engineering and Technology A new type of monolithic piezoelectric bending actuator called reduced and initially baised oxide

wafer(RAINBOW) is fabricated by selectively reducing one surface of piezoelectric materials at elevated temperature.

In this study, RAINBOW composition of 0.4Pb(Ni&#8531;Nb&#8532;)O3-0.6Pb(ZrxTi1-x)O3 were prepared. Its dielectric and piezoelectric properties were investigated in the vicinity of MPB. RAINBOW actuators with different reduction layer thickness are prepared by changing reduction temperature and time. The high displacement performance of RAINBOW can be achieved by choosing a suitable thickness ratio of reduced layer to the piezoelectric layer.

E/PII.21 PHOTOLUMINESCENCE STUDY OF HIGHLY RESISTIVE P-TYPE SILICON ANODIZED IN HF/

ETHYLENE GLYCOL SOLUTIONS N. Chiboub, N. Gabouze, S. Sam, L. Guerbouze In this work, photoluminescent porous layer were formed by annodization of highly resistive p-type silicon

substrates (0.1- 10 k&#8486;cm) in HF/ ethylene glycol solutions. The substrates were illuminated with different light intensities and wavelength (energies). The proprieties of

porous silicon layer formed by this method as a function of etching time, solution concentration, illumination intensities were investigated by Scanning Electron Microscopy (SEM), X- Ray Diffraction Spectroscopy and photoluminescence (PL), Infrared Fourier Transformed Spectroscopy (IRFT). It shows that under several conditions the surface is porous and the layer thickness is not limited by an instability as observed on non-illuminated samples. Photoluminescence measurements show that the emission PL peak position and the intensity strongly depend on the HF concentration. The PL spectra exibits emission peaks at 478 nm and 650 nm, corresponding to samples anodized in 30 %HF and 50% HF in ethylene glycol, respectively. While a weak PL emission for HF concentration up to 70 % is observed. Finally, the PL results have been attributed to the variation of nanocristallites size, in agreement with the quatum confinment model.

E/PII.22 PROCESSING OF Si WIRE ARRAY FOR APPLICATION IN TELECOMMUNICATION I.P. Ostrovskii, V.M. Myshchyshyn, Lviv Polytechnic National University, 1 Kotlarevsky Str., 79013 Lviv,

Ukraine, and A.I. Klimovskaya, Institute of Semiconductor Physics of Ukrainian NAN, Kiev, Ukraine Advanced development of telecommunication demands new techniques, particularly nanotechnology. So, recently

physical aspects of teleportation on a quantum dot array, which consists in exchange of electron between quantum dots were described. The proposed idea is to use Si wire array for preservation, transferring of information, i.e., for teleportation on principles of visible luminescence signal processing.Si wires are known to be heterostructures consisted of Si strained core and porous Si envelope. Thickness of envelope is of about 5-20 nm depending on the wire diameter (500-5000 nm). Visible light electro-, photoluminescence is observed in such structures, originated from porous layers. The aim of present paper is processing of Si wire array on Si substrate and studies of its luminescence signal. The growth method consists in regular deposition of Au dots on Si substrate. Then Si substrate is loaded in a reactor of open vapour-transport system. Thermoprocessing of the reactor at 800oC provides the wires growth from Si-Au droplets according to VLS mechanism.The results of investigation of Si wire structure by AFM as well as studies of visible photoluminescence response of the wires are provided.

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E/PII.23 STRUCTURAL AND OPTICAL PROPERTIES OF POROUS-Si NANOSTRUCTURES FOR NANO-SCALE SENSORS

K. Das, S.S. Sarkar, A. Dhar and S.K Ray Department of Physics, Indian Institute of Technology Kharagpur, India

Several reports of strong visible luminescence at room temperature from porous silicon have stimulated the possibility of a Si-based optoelectronics technology. Porous silicon (PS) is also attractive for nano-scale gas/chemical sensors, because of its very large surface-to-volume ratio, high surface reactivity and its potential compatibility with conventional silicon process technology, leading to strong dependence of optical and electrical properties of PS on the environment. In this paper we report the fabrication of porous silicon with its optical and electrical characteristics. Samples were prepared by anodically etching silicon wafers in an equal volume of aqueous HF and ethanol with pore size varying from 20-80nm in diameter. The High-Resolution x-ray analysis of Si(0 0 4) reflection for the etched sample shows an additional diffraction Bragg peak, characteristic of strained Si nanowire. A shift in the peak position and broadening with increasing etching time can be attributed to increase in lattice strain and decrease in Si nanowire size on etching. A typical room temperature photoluminescence (PL) spectrum of porous silicon sample shows peak in the visible region. The shift in the Raman peak position and asymmetry can be explained by phonon confinement model for low dimensions. The C-V measurements of test structures have been carried out for sensing chemical vapors. The sensor was biased laterally between the two contacts at a constant voltage (4.5V) and the capacitance was measured. The response of the as deposited porous layers and the oxidized porous layers shows a complete reversibility indicating the reversible nature of the adsorption and the desorption process of acetone in silicon nanopores.

E/PII.24 ELECTRIC FIELD AND TEMPERATURE DRIVEN INSULATOR-METAL TRANSISIONS IN

POLYCRYSTALLINE VOX THIN FILMS Choong-Rae Cho, SungIl Cho, and InKyeong Yoo, U_team, Samsung Advanced Institute of Technology, Suwon

440-600, Korea, Jinhee Heo, Jaejin Lee and Ilsub Chung, School of Information & Communications Engineering, SungKyunKwan University, Suwon, Kyunggi-do 440-746, Korea

Insulator-to-metal transitions (IMTs) in polycrystalline VOx thin films have been performed both by applying electric field and elevating temperature. The films are prepared by using rf magnetron sputtering on Pt/Si substrates held at room temperature. Oxygen partial pressure and post-annealing conditions have been found to be critical parameters on the various properties of the films, such as structural phases, electrical conductivity, adhesion to the substrate, and reactivity towards water.

Typical current-voltage (I-V) hysteretic curves for ~400nm thick VOx layer in Pt/VOx/Pt vertical capacitor structures revealed threshold voltage, Vth, of ~0.7V and the holding voltage, Vh, of ~0.3V, respectively. On the other hand, sharp IMT transitions are observed at around 67oC in resistance-temperature (R-T) hysteresis curves in the same sample. Systematic studies for size effects; VOx thickness and electrode area dependencies, on both IMTs will be presented. To understand the mechanisms for eventual IMTs, we investigated current mapping images using conductive Atomic Force Microscope (AFM). By analyzing the correlation between current image and topology of VOx film under various biases and temperatures, we could find nano areal conductive paths and their transition behaviors. In addition, local I-V hysteresis curves are measured by conducting cantilever tip for comparison with those for in Pt/VOx/Pt structures. Based on above results, we will suggest and discuss models for both kinds of IMT in polycrystalline VOx thin films.

E/PII.25 NANOPARTICLE PATTERNING USING SELF-ASSEMBLED CONDUCTING/INSULATING BLOCK

COPOLYMERS Yi-Huan Lee(c), Chi-Jen Kao(c), Chi-An Dai(a,c), Chiun-Chi Ho(b), Wei-Fang Su(b,c), (a)Department of

Chemical Engineering, (b)Department of Materials Science and Engineering and (c)Institute of Polymer Science and Engineering National Taiwan University, Taipei, Taiwan

Nanoparticle/polymer hybrid materials have been found useful in the fabrication of devices such as light emitting diode, photovoltaic, etc. In order to achieve high device efficiency, it is desired to have nanoparticles well organized and well dispersed in the polymer matrix. We are proposing to pattern nanoparticles in self-assembled conducting/insulating block copolymers to achieve the goal. The conducting/insulating block copolymers of poly (para-phenylene)-b-Poly (2-vinyl pyridine) (PPP-PVP) were synthesized by using sequential anionic polymerization to produce a precursor of PPP-PVP, poly (1,3 cyclohexadiene)-b-poly (2-vinyl pyridine) (PCHD-PVP). PCHD-PVP copolymers were subsequently derivatized through an aromatization reaction and reduced to PPP-PVP. Block copolymers that can be self-assembled to different morphologies e.g. lamellae, cylinders and spheres were synthesized. Semiconducting nanoparticles of cadmium sulfate (CdS) was incorporated into PPP-PVP nanostructure using in-situ synthesis of CdS in the PVP domain. The structure of the nanoparticle/copolymer hybrid was determined by AFM and TEM. Optoelectronic property of the hybrid material was measured by UV-Vis absorption and photoluminescence. The structure-property relationship of the patterned nanoparticle/copolymer hybrid will be discussed.

E/PII.26 ENHANCED CARRIER INJECTION OF ORGANIC LIGHT EMITTING DEVICES USING SELF

ASSEMBLED MONOLAYER IN THE CATHODE/ORGANIC INTERFACE U. Manna(a), Sunyoung Sohn(b), Donggeun Jung(b), M. Gowtham(a), H. M. Kim(a), J.Yi(a), (a)School of

Information and Communication Engineering, Sungkyunkwan University, Suwon 440-746, Korea, (b)Department of physics, Brain Korea 21 Physics Research Division and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746, Korea

Self assembled monolayers (SAM) are generally used at the anode/organic interface to enhance the carrier injection in organic light emitting devices which improves the electroluminescence performance of organic devices. This paper reports the use of SAM of 1-decanethiol (H-S(CH2)9CH3) at the cathode/organic interface to enhance the electron injection process for organic light emitting devices. Aluminum (Al), tris-(8-hydroxyquionoline) aluminum (Alq3), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) and indium-tin-oxide (ITO) were used as bottom cathode, an emitting layer (EML), a hole-transporting layer (HTL) and a top anode, respectively. The results of the capacitance-voltage (C-V), current density -voltage (J-V), brightness-voltage (B-V) and quantum efficiency measurements show a considerable improvement of the device performance. The dipole moment associated with the SAM layer decreases the electron schottky barrier between the Al and the organic interface, which enhances the electron injection into the organic layer from Al cathode and a considerable improvement of the device performance is observed. The turn-on voltage of the fabricated device with SAM layer was reduced by 3V, the brightness of the device was increased by 5 times and the quantum efficiency of the device was increased by 0.06%.

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E/PII.27 THE IMPROVEMENT OF PENTACENE-BASED ORGANIC THIN-FILM TRANSISTOR (OTFT) BY INSERTING LITHIUM FLUORIDE (LiF) THIN LAYER BETWEEN PENTACENE LAYERS

D.S. Park, S.J. Kang, C.Y. Kim and C.N. Whang, Institute of Physics and Applied Physics, Yonsei University, Seoul, Korea

The pentacene-based organic thin-film transistor (OTFT) with inserted lithium fluoride (LiF) thin layer (1 nm) between pentacene layers was fabricated in ultrahigh vacuum (UHV) condition with all in-situ. processes, and improved electrical properties were achieved. The fabricated device structure is gold (30 nm) / pentacene / LiF (1 nm) / pentacene / SiO2 (100 nm) / p+-Si (substrate): the ratio of upper pentacene layer thickness and lower pentacene thickness was varied, keeping the sums of two pentacene layer thicknesses with 100 nm. As varying the ratio of two pentacene layer thicknesses, the field effect mobility and threshold voltage was affected. The field effect mobility increased when LiF layer was near gold layer and decreased when LiF layer was near SiO2 layer. In addition, the threshold voltage was minimum value when LiF layer was in the middle of two pentacene layers. By inserting thin LiF layer, the field effect mobility and threshold voltage increased from 0.39 cm2/Vs to 0.66 cm2/Vs and from -21.89 V to -8.65 V, respectively.

E/PII.28 DOPED AROMATIC DERIVATIVES WIDE-GAP CRYSTALLINE SEMICONDUCTOR STRUCTURED

LAYERS FOR ELECTRONIC APPLICATIONS A. Stanculescu(a), F. Stanculescu(b), H.V. Alexandru(b), M. Socol(a), (a)National Institute for Materials Physics,

P.O. Box MG 7 Magurele, Bucharest, Romania, (b)Faculty of Physics, University of Bucharest, Romania Lately organic molecular materials are considered as a potential alternative for inorganic semiconductors in the

manufacturing of electronic components and electrically active devices. To investigate the electrical conduction properties in microstructured crystalline layers of doped meta-

dinitrobenzene (m-DNB) and benzil, we have prepared sandwich type silicon /wide-gap organic semiconductor/ silicon (SIS) heterostructures. Silicon wafers properties, as resistivity and conduction type, surface processing, doping and structural defects (as local electronic states in the band gap), are strongly influencing the transport of carriers in these structures. The low intrinsic conductivity of optical wide-gap organic semiconductor, (Eg=2.8 eV in benzil respectively Eg=2.9 eV in m-DNB), have been improved by doping with [Ag(NH3)2Cl] (p-doping) or sodium (n-doping) for benzil or 1,3 dihydroxybenzene and 8-hydroxyquinoline for m-DNB. To drawn the I-V characteristics we have used a typical 2 points perpendicular contact method emphasising the effect of the pressures on the electrical resistance across the structure and on the conduction mechanism by the deformation and reorientation of the crystallites in the organic film and a strong super-linear I-V characteristic for meta-dinitrobenzene doped with 8-hydroxyquinoline suggesting potential applications in the manufacturing of the electric non-linear devices.

E/PII.29 ELECTRICAL PROPERTIES OF SOME NEW HIGH RESISTIVITY ORGANIC SEMICONDUCTORS IN

THIN FILMS L. Leontie(a), I. Druta(b), R. Danac(b), G.I. Rusu(a), (a)Faculty of Physics, "Al.I. Cuza" University, 11 Carol I

Boulevard, 700506 Iasi, Romania, (b)Faculty of Chemistry, "Al.I. Cuza" University, 11 Carol I Boulevard, 700506 Iasi, Romania;

The temperature dependence of d.c. electrical conductivity, ?, and Seebeck coefficient, S, for seven new synthesized 1-(p-X-benzoyl)-1,2,3,3a-tetrahydropyrrolo-[1,2-a][1,10]-phenanthrolin-2,3-(N-R)-dicarboximide compounds, has been investigated. Thin film samples (d=0.09-0.94 ?m) deposited by an immersion technique (from dimethylformamide solutions) onto glass were used.

XRD analyses were performed for the investigation of crystalline structure of as-prepared films, while AFM and SEM techniques, corroborated to optical microscopy were used for the examination of surface morphology. The behavior of ? and S as a function of temperature is typical for polycrystalline semiconducting (n-type) materials. The activation energy of electrical conduction laid in the range 1.21-1.82 eV, while the ratio of charge carrier mobilities ranged between 1.05 and 1.15. Static current-voltage characteristics of metal/organic compound/metal thin-film sandwich structures have been also studied. Some correlations between semiconductor properties and molecular structure of the compounds were established. The model based on band gap representation can be satisfactory used for the explanation of electronic transport in investigated compounds.

E/PII.30 PHOTO INDUCED AND PLASMA TREATMENT OF DIMETHACRYLATE-BASED POLYMER FOR

LIQUID CRYSTAL ALIGNMENT Song-Shiang Lin, Chein-Dhau Lee, Yu-Jen Chan, Vladimir Syromyatnikov, Lyudmyla Vretik, Ling-Na Tsai, Po-

Jen Chu, Yu-Der Lee Conventional rubbing process generates unwanted static electricity, dusting and non-uniformity on the surface of

LC alignment layer. Therefore, new non-rubbing methods are recently being developed such as photo or plasma alignment method. We have developed a new photosensitive material, which is applicable for polarized UV photo-induced and plasma-treated alignment layer for LCD. The synthesis and characterization of bis-methacrylic derivatives of p-aminophenol is explored. We have successfully controlled the molecular weight of the dimethacrylate-based photosensitive polymer via free radical polymerization. The polymerization selectivity of the double bonds in homopolymer can be verified with the solid state NMR. In addition, excellent alignment uniformity has been achieved by using the polarized UV photo-induced process and the anode layer thruster plasma treatment. The pretilt angle of LC cell by plasma treatment is higher than that of polarized UV treatment. The azimuthal anchoring energy generated with plasma treatment is relatively higher than that by the photo-induced process. It was comparable to that due to the rubbing mode. The dimethacrylate-based photosentive polymer can be applied to the photo induced and plasma treated LC alignment layer. Excellent uniformity suitable for treating the large-area substrates has thus been achieved.

E/PII.31 NEW ROUTE FOR PERPENDICULAR ORIENTATION OF THE DOMAIN IN PS-b-PMMA THIN FILMS M. Dutreilh-Colas(a), J.-F. Bardeau(b), Sagrario Pascual(c), Laurent Fontaine(c) and A. Gibaud(b), (a)Centre de

Recherche sur les Matériaux à Hautes Températures, UPR CNRS 4212, 45071 Orléans Cedex 02, France, (b)Laboratoire de Physique de l’Etat Condensé, UMR CNRS 6087, Université du Maine, 72085 Le Mans Cedex 09, France, (c)Laboratoire de Chimie Organique Macromoléculaire, UMR CNRS 6011, Université du Maine, 72085 Le Mans Cedex 09, France

Many self-assembling methods have been investigated to obtain well-ordered nanoscopic structures in thin films. However, the self-assembly processes alone are not sufficient to control a spatial orientation of the domain on bare substrate. In thin films, the structuration of domains is mainly governed by the surface energies of the blocks and geometrical constraints introduced by confinement. These factors are now well established in the case of PS-b-

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PMMA thin film. The control of interfacial energies and wetting behavior of polymer in contact with solid surfaces have been widely studied by the Russell group. They have shown that substrates modified by an anchored random copolymer (Surface energy is neutral with respect to each component of the diblock) or the use of electric field to overcome interfacial interactions allowed them to get arrays of hexagonally close packed domains. They observed pores with diameters ranging from 14 to 50 nm and separations distances from 24 to 89 nm as a function of molecular weight of block copolymer and thickness of film.

In our present work, we report how to form an array of nanoscopic cylindrical domains of PMMA standing up in a PS matrix without anchoring a random copolymer or applying an electric field. We used a photocleavable PS-b-PMMA polymer with a molar fraction of PS of 72%. The structural investigations of the surfaces were carried out by atomic force microscopy. The average center-to-center distance between the cylindrical domains was determined at 40 nm with an average cylinder diameter D of 23 nm. The PMMA is then removed by UV radiation in order to form a nanoporous PS matrix directly on a silicon oxide wafer. The ability of such a system to allow further elaboration of nanopatterned surfaces is currently under study.

E/PII.32 ORDERED 2D PATTERN FORMATION OF BLOCK COPOLYMER DUE TO DEWETTING PHENOMENON A.J.F. Carvalho, M.A.P. da Silva and R.M. Faria, Instituto de Física de São Carlos, University of São Paulo,

P.O.Box 369, 13560-970, São Carlos, Brazil Spinodal dewetting followed by Rayleigh instability are two phenomena used to explain micro and

submicrometric stripes and droplets formations after the deposition of a solution of polymer thin layer onto a non-wettable solid substrate. The block copolymer used in this work was Poly(styrene)-block-poly(ethene-co-butene)-block-poly(styrene)having a mass average molar mass of Mw= 112,000 g/mol with a polydispersity index Mw/Mn = 1.15; and the used solvent was toluene. Films prepared by self-assembly on mica substrate evolved into spontaneous striking arrangement of stripes and "nano-pancakes": the former exhibiting a parallel arrangement and the last one arranged in a perfect 2D hexagonal structure. The images are obtained by AFM technique with excellent resolution. Such kind of structures have been studied for lithography and microcontact applications, as well as, for nanofabrication in organic electronics.

E/PII.33 P-PHENYLENE DERIVATIVES USING PLASMA POLYMERIZATION AND BINARY MIXTURES Ioan Stamatin(a), F. Nastase(a), Claudia Nastase(a), D. Mihaiescu(b), A. Moldovan(c), (a)University of Bucharest,

Polymer Science Department, P.O. Box MG-11, 077125 Magurele – Bucharest, Romania, (b)University of Agriculture Sciences and Veterinary Medicine, 59 Marasti, Bucharest, Romania, (c)National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, 077125 Magurele – Bucharest, Romania

Poly-phenylene proved to be a good competitor in molecular electronics to build wires and rectifying devices. As chemical synthesized is not appropriate to be deposited in thin films by usual methods as spin-coating or dip-drag with solvents. To get films ready for use the plasma polymerization is one of the key route in spite of not appropriate structure are obtained as in chemistry methods. Inserting in PPP backbone other pi-conjugate systems, a large variety of heterostructures can be induced. We report a combinatorial method of plasma polymerization with direct injection of p-xylene as liquid monomer to substrate (quartz and Si-100). FT-IR and Raman show structures of PPP with 4-7 repeat units, AFM - a specific morphology from rod-like to plate-like shapes, and UV-Vis a gap from ~ 3 eV to 1.5 eV when the copolymerization with aromatics takes place from shorter to larger delocalized pi-system (antracene - biphenyl - quarterphenyl - naphthalene). In addition is showed the possibility to accommodate the conduction mechanisms from SCLC to ohmic being observed in I-V characteristics measured for each system.

E/PII.34 PULSED LASER DEPOSITION OF PENTACENE THIN FILMS I. Virt, K. Zembrowska, G. Wisz, P. Potera , M. Labuz, M. Kuzma, Institute of Physics, Rzeszów University,

Rejtana 16a, 35-309 Rzeszów, Poland Pentacene is an aromatic molecule which is already used in transistor fabrication. In this paper we study the pulsed

laser deposition growth process of thin films of pentacene. The layers were formed on various types of substrates including patterned (001) Si surfaces as well as CdTe single crystals. Morphology, grain size and homogeneity were studied by scanning electron microscopy and optical microscopy. Reflection and transmission optical spectra were collected for various thicknesses of the samples. The morphology of layers was characterised by fractal dimension calculations.

E/PII.35 IONICALLY SELF-ORGANIZED THIN FILMS OF SEMI-CONDUCTING STARDOPANT-PROTONATED

OLIGO(KETANIL)S A. Iwan, D. Sek, Centre of Polymer Chemistry, Polish Academy of Sciences, 34 M. Curie-Sklodowska Street, 41-

819 Zabrze, Poland, and J.P. Bonnet, P. Rannou, A. Pron, Laboratoire de Physique des Métaux Synthétiques, UMR5819-SPrAM (CEA-CNRS-Univ. J. Fourier-Grenoble I), DRFMC, CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble Cedex 9, France

Oligo(ketanil)s containing vinylene group in their main chain have been investigated in their neutral and protonated states. The use of a specially designed, protonating agent of C3 symmetry (so-called "stardopant"), namely 1,3,5-benzenetricarboxamide derivative with -(CH2)2SO3H groups induces the formation of ordered supramolecular organizations in thin solid films of protonated-oligo(ketanil)s. Depending on the processing solvent used (aprotic DMA vs. protic m-cresol) the polarized optical microscopy (POM) investigations have shown the presence of feather-like vs. spherulite-like morphologies spanning over different length scales. The POM findings have been additionally corroborated by specific thermal transition features detected in their DSC curves. Protonation-induced changes in the absorption and emission spectra of these ionically self-assembled organic semi-conducting thin films are discussed in relation with their supramolecular organization.

E/PII.36 NEW FUNCTIONAL MATERIALS ON THE BASE FLUOROCONTAINING THERMOSTABLE POLYMERS E.V. Sheludko, G.A. Kovtun, O.N. Tsypina, Institute of Bioorganic Chemistry and Petrochemistry, National

Academy of Science of Ukraine, 1 Murmanskaya ul., 02094 Kyiv, Ukraine and Z.I. Kazantseva, P.S. Smertenko, S.V. Svechnikov, V. Lashkarev Institute of Semiconductors Physics, National Academy of Sciences of Ukraine, 45 prospekt Nauki, 03028 Kyiv, Ukraine

The development of novel nanomaterials (ultrathin films and their multilayer compositions) is of prime importance for progress of micro- and nanoelectronics. In this respect the use of thermostable heterochain fluorinated polymers-based ultrathin films is of special interest. Fluorocontaining thermostable polyheteroarylenes exhibit increased thermal stability, hydrophobicity and lipophobicity, chemical resistance and decreased intermolecular attractive forces in comparison to their hydrocarbon analogues. The composite molecular films will be formed by

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a step-by-step molecular engineering process that includes a combination of selective molecular adsorption on a surface, self-assembling and chemical binding to the surface, and LB transfer. Developed materials are applied as ultrathin molecular films (Langmuir-Blodgett films) for interlayer insulation of IC - chips (e = 2,3), self - assembled monolayers (SAMs) for modification of surface moving devices (for example, microvibromotors) components of MEMS and NEMS (friction factor f = 0,06-0,07), resistors that are proof against ionizing radiation, sensors and biocomposites.

E/PII.37 SURFACE POTENTIALS OF LAYER-BY-LAYER FILMS FROM NICKEL PHTHALOCYANINE AND

POLY(ALLYLLAMINE HYDROCHLORIDE) Josmary R. Silva(a), Nara C. de Souza(b), José A. Giacometti(b), Osvaldo N. Oliveira Jr (a), (a)Instituto de Física

de São Carlos, Universidade de São Paulo, CP 369, 13560 – 970, São Carlos, SP, Brazil, (b)Faculdade de Ciências e Tecnologia, Universidade Estadual Paulista, CP 467, 19060-900, Presidente Prudente, SP, Brazil

We investigate the surface potentials of layer-by-layer (LbL) films of tetrasulfonated nickel phthalocyanine (NiTsPc) alternated with poly (allyllamine hydrochloride) (PAH), and deposited on metallic substrates. Because the surface potential results from molecular dipole moments, injected charges from the electrodes and impurities in the film, it is found to depend on the various film fabrication conditions, such as pH and concentration of the solutions, and the number of bilayers deposited. The mechanisms responsible for the surface potential are discussed.

E/PII.38 RADIOFREQUENCY PLASMA TREATMENTS OF POLYMERIC NUCLEAR TRACK MEMBRANES:

MODIFICATION OF MORPHOLOGICAL, CHEMICAL AND PERMEATION PROPERTIES A. Lazea, G. Dinescu, M. Dinescu, National Institute for Plasma Lasers and Radiation Physics, Magurele MG-16,

077125 Bucharest, Romania L. Kravets, S. Dimitriev, Joint Institute for Nuclear Research, Flerov Laboratory of Nuclear Reactions, Dubna, Russia

The irradiation of polyethylene terephtalate thin foils with high energy accelerated ions followed by chemical removal of material along the ions trajectories was used for nuclear track membranes fabrication with narrow distributions of the pores size. The pores diameter is in the range of hundreds of nanometers. The membranes were submitted to radiofrequency (13.56 MHz) plasma treatments (air, ammonia) leading to the modification of morphological, chemical and permeation properties. The increase of roughness and modification of pores shape and size is noticed by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Either increase or decrease of the foils thickness was noticed which relates to etching or re-polymerization phenomena. The chemical nature of the surface changes, as shown by Electron Spectroscopy for Chemical Analysis (ESCA) investigations and contact angle measurements. This is due to surface functionalization by plasma species. Depending on the treatment parameters (rf power, gas pressure, duration) hydrophilic or hydrophobic surfaces compared to the initial ones were obtained. The plasma treatments lead to modification of water permeability through membranes, opening the way for improving their transport properties.

E/PII.39 THE EFFECTS OF THERMAL TREATMENTS AND DENDRIMERS CHEMICAL STRUCTURES ON THE

PROPERTIES OF HIGHLY SURFACE CROSS-LINKING POLYIMIDE FILMS Youchang Xiao, Tai-Shung Chung, Department of Chemical & Biomolecular Engineering, National University of

Singapore, 10 Kent Ridge Crescent, 119260 Singapore We have conducted an extensive study to investigate the effects of thermal treatments and dendrimers' structures

on the chemical and physical properties of the surface modified polyimide films. The amidation and cross-linking reaction between G0 PAMAM dendrimers and polyimide were examined by XPS (X-Ray Photoelectron Spectrometer) and FTIR-ATR (Attenuated Total Reflection) measurements after thermal treatments under different temperatures. Moderated thermal treatment (120oC) is proved to be able induce the highly amidation reaction and increase the degree of cross-linking on the polyimide surface. The gas separation performance of modified polyimide films is significantly improved, due to the enhanced "molecular sieving" ability by dendrimer modification, and the stronger interactions between the polyimide chains, such as covalent cross-linking bonding and hydrogen bonding. When the temperature of treatment reaches to 250oC, 1H-NMR and GPC test implied that the cross-linking structure between polyimide chains is broken and the degradation of polyimide backbone chains also occurs. Gas permeation tests also indicated that high temperature treatment of dendrimer modified polyimide films is not benefit to separation. In addition, the performance comparison between different dendrimers PAMAM and DAB modified films is carried out. The chemical structural differences in PAMAM and DAB dendrimers have also been verified as one of the important factors in determining the properties of modified polyimide films. At room temperature, PAMAM dendrimers show stronger cross-linking ability.

E/PII.40 SIMULATION OF SILICON NANOWIRE ENSEMBLE FORMATION BY CATALYTICALLY ENHANCED

CVD A.A. Efremov(a), A.I. Klimovskaya(a), T.I. Kamins(b), S. Sharma(b), R.S. Williams(b), (a)Institute of

Semiconductor Physics, National Academy of Sciences, Kyiv 03028, Ukraine, (b)Quantum Science Research, Hewlett-Packard Laboratories, Palo Alto CA 94304, USA

A phenomenological model for Au and TiSi2 catalyzed growth of dense ensembles of silicon nanowires on silicon substrates by a SiH4+H2 CVD process is developed. Gas phase delivery to the catalyst particle surface, silane chemisorption, and molecular transport inside the "forest" of nanowires, followed by direct silane adsorption on the nanowire side are considered. In addition, silicon adatom migration through and around the liquid or solid catalyst nano-particle, across the nanowire/catalyst interface and along the nanowire sidewall are included in the model. By including the relevant processes, both axial and radial growth, and the shape of the nanowire are predicted by the simulations.

A characteristic feature of such growth is that the molecular transport inside the ensemble is governed by the Knudsen effect, providing additional separation of the active gas and the gas carrier. Dependencies of growth rate and kinetics of nanowire shape formation on the main macroscopic parameters of the process are presented and compared with experimental data.

E/PII.41 MODELLING THE EFFECTS OF MESOSTRUCTURE ON ELECTRONIC APPLICATIONS OF POLYMER

THIN LAYERS Marta M.D. Ramos, Helena M.G. Correia, Hugo Carmo, Departamento de Física, Universidade do Minho,

Campus de Gualtar, 4710-057 Braga, Portugal There is considerable experimental evidence that the microstructure has important consequences for polymer-

based electronic and optoelectronic applications but few theoretical and computational models account for it. We

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produced several realisations of polydiacetylene networks exhibiting specific microstructures at the mesoscopic scale and we carried out computer experiments in which bipolar charge carriers were injected in the polymer system from the appropriate electrodes. The electronic properties of each polymer molecule were obtained from self-consistent quantum molecular dynamics calculations.

In the calculations reported here we explicitly include the percolation in charge transport, the recombination and the effects of other charges within the polymer layer as well the polarisation of the electrodes. Our results show that polymer microstructures resulting from different arrangements of polymer molecules have significant effects on the competition between charge trapping, current transport and recombination within the polymer layer.

E/PII.42 THE EFFECT OF FINITE FILM THICKNESS ON THE CRYSTALLIZATION KINETICS OF AMORPHOUS

FILM AND MICROSTRUCTURE OF CRYSTALLIZED FILM Vladimir I. Trofimov, Ilya V. Trofimov, Institute of Radioengineering & Electronics of RAS, 11/7 Mokhovaya

Street, 125009 Moscow, Russia and Jongil Kim, Cheonan Valley, CN-Regional Innovation Agency 43-5, Sameun-Ri, Jiksan-Eup Cheonan-Si, Chungnam-Do 330-816, South Korea

Model for crystallization kinetics of thin amorphous film is developed by extension a familiar Kolmogorov-Johnson-Mehl-Avrami (KJMA) model to take into account a finite film thickness. Two model versions: volume induced (VIC) and surface induced crystallization (SIC) with two nucleation mode: instantaneous nucleation (IN) at the process onset and continuous nucleation (CN) in the uncrystallized region are explored. The crystallites grow isotropically at constant rate before impingement and growth ceases where they impinge but continues in all other available directions. For all these model versions (CN-VIC, IN-VIC, CN-SIC and IN-SIC) a temporal evolution of the crystallized volume fraction, crystallites density and their profile distribution across a film are derived. Finite film thickness effects lead to important consequences in the VIC-behaviour: the crystallization profile reaches a maximum in film middle, whereas that of the crystallites density has a minimum, the crystallites population in a film is always higher than in a volume material, the thinner film the slower it crystallizes, and a spatially inhomogeneous microstructure with a fine-grained subsurface layer is formed. The VIC - kinetics follows a generalized KJMA equation with parameters depending on a film thickness and in extremely thin and thick film it reduces to classical 2D and 3D KJMA equation, respectively, and a film thickness range of the validity of the KJMA model is found. The SIC-kinetics obeys 2D KJMA equation in sufficiently thin film and is nearly linear in a thick film. The model is extended to the case of non-constant growth rate (non-isothermal annealing) and the crystallization of subsurface film layer, and comparison with experiment is presented.

E/PII.43 THEORETICAL ABSORPTION SPECTRA OF SILICON CARBIDE NANOCRYSTALS S.L. Shi and S.J. Xu Department of Physics and HKU-CAS Joint Laboratory on New Materials, The University of

Hong Kong, Pokfulam Road, Hong Kong, China, X.J. Wang and G.H. Chen, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China

Silicon Carbide (SiC) is an important wide gap semiconductor with many outstanding physical and chemical properties. Its nanostructures are attracting an increasing interest. In this presentation, we report on theoretical absorption spectra of 3C-SiC nanocrystals with different sizes and different surface termination foreign atoms using the semiempirical PM3 localized-density-matrix method. Pronounced size dependence of the absorption spectra is clearly demonstrated. Besides size effect, the influence of the surface configurations on the optical property of SiC nanocrystal is also studied. The absorption spectra of 3C-SiC nanocrystal terminated with OH or NH2 species are calculated. Compared with H-terminated case, the absorption edge of OH-terminated or NH2-terminated 3C-SiC exhibits a significant red shift. It is also found that there are more fine structures appearing at the lower energy side of the dominant absorption peak (~ 4.4 eV) for OH-terminated 3C-SiC nanocrystals.

E/PII.44 SYNTHESIS AND CHARACTERIZATION OF HIGHLY CONCENTRATED SILVER NANO SOL FOR

INKJET PRINTING Beyong-Hwan Ryu, Youngmin Choi, Han-Sung Park, Jong-Hoon Byun, Kijeong Kong, and Jeong-O Lee,

Advanced Materials Division, Korea Research Institute of Chemical Technology, Korea Recently the inkjet patterning technique has been expected to form a metal interconnects in flat panel displays, to

reduce processing cost especially for plasma and other large-size displays. However, a novel inkjettable conductive ink or metal paste instead of conductive polymer would be necessary to obtain enough conductivity for electrode interconnects.

The objectives of this study are the development of novel inkjettable conductive ink as a key material for flat panel display. The synthesis of highly concentrated silver nano sol assisted by polyelectrolytes for inkjet method was studied. The role of polyelectrolytes on the synthesis of silver nano sol was studied by varying molecular weights and the molar ratios (R=[COO-]/[Ag+]) of them. The concentrated silver nano sol was synthesized by reducing the cation (Ag+) and anionic polyelectrolytes (COO-) complex including the step of initial nucleation and growth of silver nanoparticles to achieve dispersion stability and controlling the size of silver nanoparticles. The maximum concentration of batch-synthesized silver nano sol was possible to 40 wt%. At the same time the particle size of silver nanoparticles was below 10~20nm. The synthesized silver nano-sol was tested the possibility of micro-patterning of electrode on ITO glass. The connectivity, width, and height of fine line depended largely on the wettability of silver nano-sol on ITO glass. These relationships will be understood by wetting angle. The fine line of silver electrode as fine as 50~100&#13211; was successfully formed on ITO glass. Furthermore, we could design the Ag nano sol, which could directly form the fine line on bare ITO glass.

E/PII.45 NUCLEATION AND COALESCENCE PROCESS OF Ag ON POLYMER SUBSTRATE I. Prosyčevas(a), J. Puišo(a,b), A. Juraitis(a), S. Tamulevičius(a,b), M. Andrulevičius(a), B. Čyžiūtė(b), (a)Institute

of Physical Electronics of Kaunas University of Technology, Savanoriu 271, Kaunas 50131, Kaunas, Lithuania, (b)Department of Physics, University of Technology, Studentu 50, Kaunas 51368, Lithuania Processes of nucleation and shaping of nanostructures on surface on polymer substrates were investigated. Ag thin films (thickness 20-100 nm) were deposited on PET by e-beam evaporation in vacuum. XRD and AFM were employed to study structural and morphological changes of the films. Surface composition of these films was investigated by XPS. It was found that the size of nanostructured formations can be changed by the evaporation rate and substrate temperature (essentially reaching the polymer glassing temperature region -80°C). Changes optical and electrical properties after thermal treatment (140°C) were registered by optical absorption and ressitivity measurements. It is shown that annealing of the discontinuous films on PET at temperatures close to the polymer glassing temperature brings about the formation of a transient nanocomposite layer.

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E/PII.46 CONTROL OF THE SURFACE ROUGHENING IN THE EPITAXIAL GROWTH OF MANGANITE FILMS F. Sánchez, I.C. Infante, Ll. Abad, U. Lüders, Ll. Balcells, B. Martínez, J. Fontcuberta Institut de Ciència de

Materials de Barcelona, CSIC, Campus U.A.B., 08193 Bellaterra, Spain To fabricate magnetic tunnel junctions the morphology of the films is a key, and two-dimensional (2D) growth and

very smooth film surfaces are required. In the epitaxy of manganites like La2/3Ca1/3MnO3 is frequently found a roughening transition at low thickness: growth starts by a layer-by-layer mode, but roughness increases fast as three-dimensional islands form on the surface. We have analysed the morphology of La2/3Ca1/3MnO3 epitaxial films in several series (thickness, substrate temperature, substrate miscut angle). Here we report on the roughening process and the methods to avoid it.

The roughening is due to the formation of "wedding-cake" islands. Initially, there are 2D islands on the surface, but before the full coverage of the layer, new 2D islands nucleate and grow on the top. As new 2D layered islands grow, the "wedding-cake" islands form. We demonstrate that the islands do not appear if the growth is by step flow mechanism. Alternatively, if the growth is by layer-by-layer, the growth processing parameters can be adjusted to tailor the islands size or to prevent its formation. These findings get insight on the epitaxy of complex oxides and provide rules to control the morphology in manganite epitaxy for the standards required to fabricate magnetic tunnel junction devices.

E/PII.47 GIANT STEP BUNCHING IN EPITAXIAL SrRuO3 FILMS ON VICINAL SrTiO3(001) F. Sánchez(a), G. Herranz(a), C. Ferrater(b), M.V. García-Cuenca(b), M. Varela(b), J. Fontcuberta(a), (a) Institut

de Ciència de Materials de Barcelona, CSIC, Campus U.A.B., 08193 Bellaterra, Spain, (b) Dep. de Física Aplicada i Òptica, Universitat de Barcelona, Diagonal 647, Barcelona 08028, Spain

Step bunching is a growth instability that can typically occur in epitaxy under step flow mechanism and that origins wide film terraces separated by steps several lattice unit cells high. In SrRuO3 films on vicinal SrTiO3(001) step bunching is giant, with steps even more than 30 unit cells high. Thus, the surfaces are suitable to be used as templates for the growth of other functional materials. Moreover, the giant size favours the study of the formation of the bunching, a phenomenon of still unclear origin. Therefore, we investigated the progression of the morphology with the film thickness. At early stages there are wedge-like islands, likely formed from initial two-dimensional (2D) plates nucleated at the substrate steps. The wedge-like islands become wider and straighter when coalesce until turning into terraces. The terraces are separated by macrosteps with the height of the front edge of the wedge-like islands just prior its coalescence. The results show that 2D islands can grow from nucleation at steps and that bunching phenomena can occur without true step flow growth mechanism. Considering that the growth starts by nucleation at steps, the formation of terraces of a width of several substrate terraces is a self-organized process. Moreover, taking profit of the formation by nucleation, we demonstrate that bunching size can be tailored by adjusting the growth rate.

E/PII.48 STRAIN EFFECT AND CURRENT-INDUCED ELECTRORESISTANCE IN EPITAXIAL THIN FILMS OF

LA0.9SR0.1MNO3 H. Yao, F. X. Hu, and J. Gao Department of Physics, The University of Hong Kong, Pokfulam Road, Hong

Kong, China As the doping level x changed, the compounds La1-xSrxMnO3 exhibit a rich variety of electronic, magnetic, and

structural phasese.[1] La0.9Sr0.1MnO3 in bulk displays insulating behavior in the whole temperature range. In our study, attentions were focused on the strain effect and current-induced electroresistance(ER) in La0.9Sr0.1MnO3 thin films, which were deposited on SrTiO3(100) substrates by using Pulsed Laser Deposition(PLD) with a thickness varying from 10nm to 50nm. We find that an insulator-metal transition can be developed with decreasing the thickness of the film. The strain compression of the lattice induced by substrate strongly influences the static Jahn-Teller distortion and causes an increase of double exchange interaction. Subsequently, the metallic conductivity was observed blow Curie temperature TC. The current-induced ER illustrates the influence of an electric current on the transport properties. On a film of 100 nm thickness with TC near room temperature deposited by adjusting oxygen content, significant reduction in resistance was induced by a dc current. The reduction of the peak resistance reaches &#65374;34% for current increasing from 0.01mA to 5mA(current density changed from 200 to 100000 Acm-2 ). This behavior is similar to that of La0.7Ca0.3MnO3 and La0.85Ca0.15MnO3 films.[2] The large reduction of the peak resistance may be ascribed to the strong interaction between carrier spins and localized spins in Mn ions, and the percolative mechanism of phase separation.

This work has been supported by the Research Grant Council of Hong Kong (Project No. HKU 7024/04P) and the National Natural Science Foundation of China (Project No. 10474066). [1] A.Urushibara,et al,Phys.Rev.B 51, 14103(1995) [2] J.Gao,et al, Appl.Phys.Lett. 82, 4732(2003)

E/PII.49 STRUCTURAL AND MAGNETIC CHARACTERISTICS OF FeCo THIN FILMS MODIFICATED BY

COMBINATORIAL ION IMPLANTATION S. Groudeva-Zotova, A. Savan, J. Feydt, B. Wehner, T. Walther, A. Ludwig, CAESAR, L.-Erhard Allee 2, 53175

Bonn, Germany, and H. Karl, B. Stritzker, University of Augsburg, 86135 Augsburg, Germany Sm implanted FeCo thin films can serve as precursor for synthesis of multi-phase exchange-spring magnetic

materials. This work presents results on the magnetic properties modification of as-implanted samples induced by high dose Sm, Xe and combined (Xe+Sm) ion implantation into magnetron sputtered FeCo thin films. A combinatorial approach was applied in order to screen a wide range of implantation doses up to 1.6e17 at/cm2 and to study the differences between pure Sm- and (Xe+Sm)- implanted samples.

Selected material libraries of as-implanted films were investigated by EDX and SIMS analysis for the film composition and the depth profile distribution, TEM and XRD analysis for the film morphology and crystalline structure, VS-magnetometry for the magnetization behaviour and texture; 4-point probe measurements for the film resistivity. Two main effects were found on the basis of this combinatorial study: strong in-plane magnetic texture only in the pure Sm implanted samples, and local maxima in the Hc and Hk values for specific doses above 1e16 at/cm2. The XRD spectra of the libraries show that both effects are closely related to the film strains introduced by the implantation process.

E/PII.50 PREPARATION AND CHARACTERIZATION OF ZNO-BASED NANOSTRUCTURED AND

NANOPOROUS THIN LAYERS Virginie Feuillad(a), Lívia Naszályi(a,b), Z. Hórvölgyi(b) and André Ayra(a), (a)Institut Européen des

Membranes, UMR n° 5635 CNRS-ENSCM-UMII, cc047, Université Montpellier II, Place Eugène Bataillon, 34095 Montpellier cedex 5, France, (b)Budapest University of Technology and Economics, Department of Physical Chemistry, Centre for Colloid Chemistry, 1521 Budapest, Hungary.

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E/PII.51 PREPARATION AND CHARACTERIZATION OF MESOPOROUS SILICA FILMS AS CATALYST

SUPPORTS ON BOROSILICATE GLASS O. Muraza(a), P.J. Kooyman(b), E.V. Rebrov(a), M.H.J.M. de Croon(a), J.C. Schouten(a), (a)Laboratory of

Chemical Reactor Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands, (b)National Centre for High Resolution Electron Microscopy, Delft University of Technology, Delft, The Netherlands

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Friday, June 3, 2005 Morning Vendredi 3 juin 2005 Matin Session VIII : Environmental and analytical applications: membrane separation, catalysis, sensors Session chairs : Jin-Ho Choy and Corinne Gerardin E-VIII.07 8:30 TiO2 THIN-FILMS ON POLYMER SUBSTRATES AND THEIR PHOTOCATALYTIC

ACTIVITY Jae-Hun Yang(a,b), Yang-Su Han(b) and Jin-Ho Choy(a), (a)Intelligent Nanohybrid

Materials Laboratory, Division of Nanoscience & Department of Chemistry, Ewha Womans University, Seoul 120-750, Korea; (b)School of Chemistry and Molecular Engineering, Seoul National University, Seoul 151-747, Korea

We have developed dip-coating process for TiO2-thin film on polymer substrates (acrylonitrile-butadiene -styrene polymer: ABS, polystyrene : PS). At first, a monodispersed and transparent TiO2 nanosol solution was prepared by the controlled hydrolysis of titanium iso-propoxide in the presence of acetylacetone and nitric acid catalyst at 80&#8451;. Powder X-ray diffraction patterns of the dried particles are indicative of crystalline TiO2 with anatase-type structure. According to the XRD and transmission electron microscopy (TEM) studies, the mean particle size was estimated to be ca. 5 nm. The transparent thin films on ABS and PS substrates were fabricated by dip-coating process by changing the processing variables, such as the number of dip-coating and TiO2 concentration in nano-sol solution. Scanning electron microscopic (SEM) analysis for the thin film samples reveals that the acetylacetone-modified TiO2 nanosol particles are effective for enhancing the interfacial adherence between films and polymeric substrates compared to the unmodified one. Photocatalytic degradation of methylene blue (MB) on the TiO2 thin-films has also been systematically investigated.

E-VIII.08 8:45 TIO2 MESOPOROUS THIN LAYER-BASED PHOTOCATALYSTS FOR VISIBLE

LIGHT GAS-PHASE TOLUENE DEGRADATION Florence Bosc, David Edwards, Nicolas Keller, Valérie Keller, Laboratoire des Matériaux,

Surface et Procédés pour la Catalyse, UMR 7515 CNRS, and ELCASS (European Laboratory for Catalysis and Surface Sciences), Université Louis Pasteur, 25 rue Becquerel BP 08 67087 Strasbourg Cedex 2, France, and André Ayral, Institut Européen des Membranes, UMR 5635 CNRS, ENSCM, Université de Montpellier II, CC047 – Place Eugène Bataillon, 34095 Montpellier Cedex 5, France

Photocatalysis has proved to be very promising for the purification of polluted air. We report on the use of coupled photocatalysts made of anatase TiO2 mesoporous thin layer supported WO3 nanoparticles for gas-phase toluene degradation with visible light (VL) activation. This photoexcitation usually requires semi-conductors with band gaps lower or equal to 3.0 eV, such as WO3 or rutile TiO2, thus ruling out the sole use of the 3.2 eV band gap anatase phase. The mesoporous thin layers were obtained by dip-coating of an anatase sol onto slides of soda lime-silica glass, which was subsequently mechanically removed. This sol was first prepared by introducing a templating mesophase into a room temperature-aged anatase hydrosol [1]. Depending on the template, hexagonal or cubic structures were finally obtained. WO3 was introduced by impregnating the anatase mesostructure with a paratungstate precursor aqueous solution. The coupling of low contents of WO3 (4wt.%) with TiO2 mesoporous anatase achieved high degradation levels, around the efficiency of WO3 coupled to pure rutile phase, and twice that of WO3 coupled to standard sol-gel anatase. The hypothesis of a confinement effect of the toluene inside the mesoporous structure will be put forward and developped to explain how a low amount of VL-activated WO3 leads to high performances using non VL-activated anatase as co-photocatalyst. This confinement would increase the partial pressure of the pollutant on the photocatalyst surface and thus the degradation activity. [1] F. Bosc, A. Ayral, P.-A. Albouy, C. Guizard, Chem. Mater. 15 (2003) 2463.

E-VIII.09 9:00 A GENERAL CO-CONDENSATION PROCESS LEADING TO HIGHLY

FUNCTIONALISED ORDERED MESOPOROUS SILICA FILMS: GENERAL APPROACH AND APPLICATION AS ADVANCED SELECTIVE OPTICAL SENSORS

L. Nicole, F. Cagnol, D. Grosso, C. Boissière, C. Sanchez, Laboratoire de Chimie de la Matière Condensée, UMR 7574, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 5, France

Various organic moieties, such as alkyl, amine, pyrrole, pyridine, methacylate, isocyanate, phenyl, mercaptopropyl or diphenylphosphine, were homogeneously co-condensed with silica precursors in presence of surfactant molecules in order to produce mesostructured hybrid porous thin films of optical quality. Influences of these sylilated functions, presenting different physico-chemical properties, on the self-assembly mechanism and on the final mesostructure were investigated using in-situ SAXS experiment and TEM analyses. The example of an accurate and selective optical sensor, composed of functionalised B-diketone silica films, exhibiting mono, bi and tri dimensional highly ordered mesostructures is detailed.

These porous films were successfully tested for selective detection of metal cations such as Fe(III), Cu(II) or U(VI) by direct absorbance at the ppm level, while homologous non mesoporous films provided no sensing properties. In addition, they are promising matrix for BF3 or benzene gas sensing by fluorescence.

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E-VIII.10 9:15 A SELECTIVE CHEMICAL SENSOR BASED ON PLASMONIC RESPONSE OF PHOSPHININES-STABILIZED GOLD NANOPARTICLES HOSTED ON A PERIODICALLY ORGANISED MESOPOROUS SILICA THIN FILM

A. Moores(a), F. Goettmann(b), P. Le Floch(a), C. Sanchez(b), (a)Laboratoire «Hétéroéléments et Coordination» UMR CNRS 7653 (DCPH), Département de Chimie, Ecole Polytechnique, 91128 Palaiseau cedex, France, (b)Laboratoire de Chimie de la Matière Condensée, UPMC-CNRS, 4 place Jussieu, 75005 Paris, France

Due to the increasing number of biological and environmental issues, reliable, sensitive, selective and user friendly chemical sensors have become more and more attractive.[1] Among various optical methods, the position of the surface plasmon band (SPB), a specific absorbance in the UV-visible spectrum of both metal layers and nanoparticles (NPs), has been widely used.[2, 3] Besides, it is well known that the capability of a coordinated ligand to increase or decrease electron density in NPs strongly influences the position of the SPB in solution. This property had never been directly used as transducer for designing sensors. Recently, our group performed the first synthesis of sp2 phosphorus hybridised gold NPs stabilised by phosphinine ligands.[4] These objects were thought to be ideal candidates for following ligand exchange processes with phosphines and thiols by UV-visible spectroscopy.

Herein we present these displacement reactions as well as the sensitivity of the UV-visible plasmon peak spectroscopy for the detection of this exchange. In order to provide an integrated detection system, we have also hosted the nanoparticles in a periodically organised mesoporous silica thin film, which is a novelty in the field. The organisation of the silica porous host shaped as thin films provides better accessibility, sensibility and faster responses than conventional amorphous oxide based hosts. [1] A. B. Ellis, D. R. Walt, Chem. Rev. 2000, 100, 2477-2738. [2] J. Homola, Anal. Bioanal. Chem. 2003, 377, 528-539. [3] J. J. Shi, Y. F. Zhu, X. R. Zhang, W. R. G. Baeyens, A. M. Garcia-Campana, Trac-Trends Anal. Chem. 2004, 23, 351-360. [4] A. Moores, F. Goettmann, C. Sanchez, P. Le Floch, Chem. Comm. 2004, 2842-2843.

E-VIII.11 9:30 HYBRID MESOPOROUS NANOREACTORS AS NEW SENSORS FOR BORON TRIFLUORIDE AND BORON TRICHLORIDE

Loïc Legagneux(a),Thu-Hoa Tran-Thi(a), Peter Hesemann(b), Jöel Moreau(b), Lionel Nicole(c), D. Grosso(c), C. Boissiere(c), A. Quach(c), Clément Sanchez(c), (a)CEA/Saclay, DSM/DRECAM/SPAM, Laboratoire Francis Perrin, URA CNRS 2453, 91191 Gif-sur-Yvette Cedex, France, (b)Ecole Nationale Supérieure de Chimie, UMR 5076, 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 5, France, (c)Laboratoire de Chimie de la Matière Condensée, UMR CNRS 7574, Université Pierre et Marie Curie, 4, Place Jussieu, 75252 Paris Cedex 05, France

Among the ordered and constrained media that have been investigated in the literature, porous solids such as silica, zeolites, alumina were found to provide nanocages in which the reactivity of organic compounds could be enhanced [1] or catalysed by the surface [2]. In the present work, we investigate the reaction of beta-diketones incorporated in mesoporous hybrid silicas, with boron trifluoride and trichloride, two gases commonly used in semiconductor industry.

In solutions, it is well known that boron trifluoride etherate reacts with beta-diketones to yield the difluoride adduct [3] while the reaction with boron trichloride gives a boronium salt. These two reactions are re-investigated, in the absence of solvent, in a variety of mesoporous thin films doped with beta-diketone and displaying either cubic, or 3D-hexagonal and lamellar phase. We demonstrate that borohalogen gases react easily with beta-diketones yielding strongly absorbing and luminescent adducts, whose intensity can be used to quantify the gas concentration. We will provide the description of all the steps, from the synthesis of the sylilated beta -diketone to the characterisation of the structures of the various organized mesoporous silica matrices grafted with &#61538;-diketones, via X-rays diffraction, transmission electron microscopy, atomic force microscopy and to the optical detection of the product reaction via absorption and fluorescence spectroscopy. References [1] V. Ramamurthy (Ed), Photochemistry in organized and confined media, VCH publishers, New York, 1991) [2]G. B. Carter, J. Dewing, N. W. J. Pumphrey, Catalysis, Proceedings on the 5th international congress on catalysis, 2, 1445, (1973). [3] N.M.D. Brown, P. Bladon, J. Chem. Soc. A, 69, 526, (1969)

E-VIII.12 9:45 THIN FILMS OF NANOSTRUCTURED UREASE - LAYERED DOUBLE HYDROXIDE

HYBRID MATERIALS FOR APPLICATION AS UREA BIOSENSORS S. Vial, C. Forano, Laboratoire des Matériaux Inorganiques, CNRS 6002, Université Blaise

Pascal, Aubière cedex, France, B. Mailhot, Laboratoire de Photochimie Moléculaire et Macromoléculaire, CNRS 6505, Université Blaise Pascal, Aubière cedex, France, H. Barhoumi, C. Martelet, N. Jaffrezic, CEGELY, UMR 5005, Ecole Centrale de Lyon 69134 Ecully Cedex, France

Immobilization of enzymes in Layered Double Hydroxides (LDH) constitute a new generation of bioinorganic hybrid materials to find applications as biosensors. Indeed, due to their high anion exchange capacities and their opened layered structure, LDH are very appropriate inorganic host structures for the intercalation of high amount of enzymes, an easy accessibility to the molecular target and the preservation of biological integrity. The self-assembling and the nanostructuration of the biomolecules/LDH hybrid system are determining parameters for the biosensor performances, and can be tailored by well adapted "Chimie Douce" synthetic processes and the realization of bioinorganic thin films. Our study concerns the preparation of urea biosensors for medical or environmental diagnosis, built from the confinment of urease in [Zn-Al] LDH structures. We will present unique results either on the immobilization of urease in LDH but also on the preparation, for the first time, of LDH thin films by the Langmuir-blodgett technique, and their structural (XRD) and textural (SEM, TEM, AFM) characterizations. The structures and the stabilities of the

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air-water interface urease/LDH and LDH monolayers will be discussed on the basis of the p-A isotherms. The biosensors have been realized by urease/LDH films deposited on IS surface and their electrochemical performances (sensitivity, Vmax) analyzed by capacitance-potential C(V) measurements under various urea concentrations.

E-VIII.13 10:00 NiO/Fe2O3 POLYMER THICK FILMS AS ROOM TEMPERATURE GAS SENSORS K. Arshak and I. Gaidan, Microelectronic and semiconductor Research Group, ECE

Department, University of Limerick, Plassey Technological Park, Limerick, Ireland Thin films based on iron oxide (Fe2O3) and zinc oxide (ZnO) prepared by Liquid Phase

Deposition on interdigitated gold electrodes has been used to detect CO and NO2 at an operating temperature of 150-400°C [1]. NiO films were used to detect other gases, such as methanol, toluene and chloroform operating at temperatures of 400-600°C [2]. This work investigates the use of NiO/Fe2O3 as a polymer thick film gas sensor that works at room temperature (RT). Various compositions of NiO and Fe2O3, e.g. 75/25, 50/50 and 25/75 wt. %, were used to form the thick films pastes. These pastes were then screen-printed onto glass substrates with interdigitated Ag electrodes. The final composition of each film was determined using XRD analysis. The films were used to detect methanol, ethanol, propanol, toluene, Acetone and chloroform at RT. The sensitivity of the devices were defined using the formula S = 100x(Rgas - Rair)/Rair where, Rair is the resistances of the films in air and Rgas is the resistance of the exposed film. These sensors showed the highest response to propanol and toluene. The sensitivities of the films with 3 various compositions were 24.16, 18.04 and 16.3 to 5000 ppm of propanol, while for toluene the calculated sensitivities were 33.33, 22.50 and 23.44 respectively. The devices with various sensitivities may find their application in electronic nose systems. The effect of alumina and glass substrates on the sensitivities of the sensors was also studied. The sensors that were fabricated on glass substrates showed better sensitivities than those on alumina.

[1] G. Neri et al, Sens & Act. B, 2002 [2] A.James et.al Sens & Act. B, 2001 E-VIII.14 10:15 CO SENSOR ACTUALIZED FROM MESOSTRUCTURED Au-DOPED SnO2 THIN

FILMS USING SPRAY PYROLYSIS Young Kyu Hwang, Niranjan Ramgir, Hye-kyung Kim, Jin-Soo Hwang, Imtiaz S. Mulla

and Jong-San Chang, Research Centre for Nanocatalysts (RCNC), Korea Research Institute of Chemical Technology (KRICT), Yuseong, Korea

The spray pyrolysis technique has been demonstrated to get pure and Au-doped mesoporous tin oxide using a non-anionic surfactant Brij 58 and the hydrous tin chloride (SnCl4·5H2O) and hexacloroplatinic acid as the inorganic precursor and the controlled amount of water for hydrolysis under acidic conditions at ambient temperature. Thin films were deposited onto the glass substrates, at 450 oC by simple spray pyrolysis technique. The novel mesostructured tin oxide thin films with various Au concentration exhibit highly selective response towards CO. The correlation of the Au incorporation in the mesostructure with specific morphology and gas sensing behavior is discussed using scanning electron microscopy (SEM), X-ray diffraction (XRD), BET surface area, transmission electron microscopy (TEM) studies.

10:20 BREAK

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Session IX : Electronic and optical applications Session chairs : Hugh W. Hillhouse and Frank Marlow E-IX.01 11:00 -Invited- SOME CHALLENGES IN THE INTEGRATION OF SEMICONDUCTOR

TECHNOLOGY AND MOLECULAR ASSEMBLY Michael H. Bartl(a,b), David R. Rink(c), Lidong Zhang(c), Evelyn L. Hu(a,c), Galen D.

Stucky(a,b), (a)California NanoSystems Institute, (b)Department of Chemistry and Biochemistry, and (c)Department of Electrical and Computer Engineering, University of California, Santa Barbara CA 93106, USA

E-IX.02 11:30 STRUCTURE AND PROPERTIES OF LOW-N MESOPOROUS SILICA FILMS FOR

OPTICAL APPLICATIONS Denan Konjhodzic, Helmut Bretinger, Frank Marlow, Max-Planck-Institut für

Kohlenforschung, 45470 Mülheim an der Ruhr, Germany Sol-gel methods enable the controlled introduction of porosity into the materials by the use

of molecular or supramolecular templates. The porosity can be used for lowering the refractive index, for soft processing of the materials and for stress relaxations. Silica thin films are attractive for their potential use in integrated optics.

The properties and structure of the mesoporous silica films synthesized by dip-coating in evaporation induced self-assembly are investigated. In this modified sol-gel process the nonionic triblock copolymer Pluronic P123 has been used as a template. Because of their ultra low refractive index (n = 1.14), these films are interesting optical waveguide supports. A significant dependence of the formed structure on the processing conditions has been revealed allowing an appreciable structure tuning. One set of processing conditions allows the reproducible synthesis of low-n films. They are crack-free, transparent, mechanically and chemically resistant, very smooth, and sufficiently thick (1 µm) with a typical structure size of 8 nm. Under other processing conditions a novel sustained lamellar structure, that remains stable upon calcination, was synthesized. The films were characterized by angular-dependent interferometry, small angle x-ray scattering (SAXS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Onto these films 2D photonic crystals made of different materials, like P(MMA/DR-1) [1], niob and tantal pentoxide have been successfully deposited. The low-index support is needed to improve the vertical confinement of the light in the waveguide. [1] M. Schmidt, G. Boettger, M. Eich, W. Morgenroth, U. Huebner, H. G. Meyer, D. Konjhodzic, H. Bretinger, F. Marlow: Appl. Phys. Lett. 85, 16 (2004)

E-IX.03 11:45 WET SYNTHESIS OF SEMICONDUCTOR QUANTUM DOTs DISPERSED IN

POLYANILINE FOR LUMINESCENT DEVICES Rajendra Kumar Pandey, Diksha Kaushik,Madhulika Sharma, Ragini Sengar and Dhirendra

Gupta, Department of Physics,Bhopal University, Bhopal 462 026, India Electronically conducting polymer/semi conducting quantum dot structures are of

considerable scientific and technological interest for applications in nano electronics, low voltage flat panel displays, sensors etc. This study reports our results on the fabrication of polyaniline(PANI)/ semiconductor quantum dot structures via an electrochemical route for possible application as light emitting devices.. High resolution atomic force microscopy was used to investigate the morphology of the as deposited PANI films. The electrodeposited polyaniline films were found to deposit in an ordered array of polymer bundles arranged parallel to the substrate surface. Within each of the individual bundles, the PANI strands were also found to be well ordered into a close packed structures. The ZnSe quantum dots were dispersed into the PANI matrix during electropolymerisation. A uniformly dispersed self-organized quantum dot structures dispersed within the PANI matrix were seen during the morphological examination using atomic force microscopy. Devices fabricated from the PANI/Q-ZnSe structures have been found to exhibit blue shifted luminescence due to the quantum confinement of the semiconductor nano-structures. Dramatic enhancement in the luminescence has been achieved because of the presence of a refractive index boundary at the interface between the semiconductor nano particles and polyaniline

E-IX.04 12:00 INTERFACIAL STRUCTURE IN CONJUGATED POLYMER DEVICES Anthony M. Higgins(a), Simon J. Martin(b), Mark Geoghegan(b), Sasha Heriot(b), Richard

A.L. Jones(b), (a)Multidisciplinary Nanotechnology Centre, School of Engineering, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, U.K., (b)Dept of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH, U.K.

The development of electronic devices that use semiconducting polymers as their active materials has been one of the most exciting developments in polymer physics in recent years. Such devices are increasingly being made from blends or multilayers, where morphology and interfacial structure strongly influences performance. The characterisation of conjugated polymer films and the development of an understanding of the factors that control their structure draw on experience gained from the study of conventional (insulating) synthetic polymers. The work presented here focuses on the characterisation of the structure of thin films (<100 nm) containing two different types of conjugated polymer. Such films are found in devices such as light-emitting diodes and photo-voltaic cells where use of electron-transporting and hole-transporting polymers offer advantages over devices made from single homogeneous layers. Examples of such films include bicontinuous phase-separated blends and polymer-polymer bilayers. Characterisation of these films using techniques such as neutron reflectivity, scanning probe microscopy and ion beam methods will be presented, along with preliminary results on the effect of morphology on device performance.

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E-IX.05 12:15 PHOTOREFLECTANCE STUDY OF MULTILAYER STRUCTURES OF NANOCRYSTALLINE CDSE IN INSULATOR MATRIX

G. Manolis(a), D. Papadimitriou(a), and D. Nesheva(a), (a)National Technical University of Athens, Department of Physics, 15780 Athens, Greece, (b)Institute of Solid State Physics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria

Nanocrystalline multilayer structures of CdSe/SiOx and CdSe/GeS2, with layer thickness varying from 2.5 to 10 nm, were grown by a modified conventional vacuum thermal evaporation technique [1]. Low temperature photoreflectance (PR) measurements at 20 K reveal dependence of the energy band gap on the layer thickness. This dependence is for the CdSe/SiOx multilayer structures in excellent agreement with previously published theoretical predictions [2] of hole confinement in a potential well of Uh&#8776;1.3 eV in the CdSe sublayers. For the CdSe/GeS2 multilayers, it is the first direct experimental evidence of the low dimensionality of these structures. Based on the experimental results obtained, a schematic band diagram of these multilayers is suggested. Due to the low cost of the growth techniques, the nanocrystalline multiquantum wells studied may prove of high technological interest for optoelectronic applications.

[1]R. Ionov, and D. Nesheva, Thin Solid Films 213(2), 230 (1992). [2]D. Nesheva, C. Raptis, and Z. Levi, Phys. Rev. B 58(12), 7913 (1998).

E-IX.06 12:30 STRUCTURE AND "IN SITU" VIBRATIONAL ANALYSIS OF CLUSTER

ASSEMBLED SILICON THIN FILMS G. Compagnini, L. D’Urso, A.A. Scalisi, O. Puglisi, Dipartimento di Scienze Chimiche,

Università di Catania, Viale A.Doria 6, 95125 Catania, Italy Low Energy Cluster Beam Deposition (LECBD) is considered an intriguing technique to

obtain thin layers with well defined structures at the nano- and meso-scale levels, allowing novel optical, electronic and magnetic properties. In the case of covalent systems, the obtained high nanoporosity in UHV gives frequently very reactive films which can be quenched with the adsorption of different chemical species or with the use of physical procedures like thermal annealing or particle irradiations. In this work LECBD technique is used to produce cluster assembled silicon thin films (0.1-0.5 um thick) by means of a laser vaporization source. The generated clusters are studied since their formation through time of flight mass spectra. The final deposited material is analyzed "in situ" by Raman and infrared spectroscopy. A comparison of the film properties before and after their air exposure shows that the exposition induces a consistent oxidation, leading to a near-infrared luminescent SiOx layer with 1<x<2. Atomic Force Microscopy reveals also that the final material is composed by isolated silicon-rich-oxide nanoclusters responsible of the observed luminescence. The role of the clusters' structure evolution during thermal treatments on the aforementioned near infrared luminescence will be also discussed.

12:45 LUNCH