IR laser-induced process for chemical vapor deposition of polyselenocarbosilane films

IR laser-induced process for chemical vapor

deposition of polyselenocarbosilane films

Magna Santos a, Luis Dıaz a, Marketa Urbanova b, Dana Pokorna b,Zdenek Bastl c, Jan Subrt d, Josef Pola b,*

a Instituto de Estructura de la Materia, C.S.I.C., 28024 Madrid, Spainb Laboratory of Laser Chemistry, Institute of Chemical Process Fundamentals, A.S.C.R., 16502 Prague, Czech Republic

c J. Heyrovsky Institute of Physical Chemistry, A.S.C.R., 18223 Prague, Czech Republicd Institute of Inorganic Chemistry, A.S.C.R., 25068 Rez, Czech Republic

Received 24 June 2005; accepted 20 October 2005

Available online 28 December 2005

Abstract

TEA CO2 laser irradiation into gaseous mixtures of 1,3-disilacyclobutane (DSCB) and dimethyl selenide (DMS) results in infrared multiple

photon-induced, non-interacting homogeneous decompositions of both educts, one yielding silene (H2Si CH2) and the other elemental selenium

as major products. The reaction between polymerizing silene and agglomerizing Se leads to chemical vapor deposition of novel polyseleno-

carbosilane films which are unstable in atmosphere. The laser induced co-decomposition represents a new process in allowing (i) reaction between

thermally generated transient and element and (ii) chemical vapor deposition of the product of this reaction.

# 2005 Elsevier B.V. All rights reserved.

Keywords: Polyselenocarbosilane films; Selenium; Laser decomposition; 1,3-Disilacyclobutane; Dimethyl selenide

www.elsevier.com/locate/jaap

J. Anal. Appl. Pyrolysis 76 (2006) 178–185

1. Introduction

There is continuing interest in the production of heteroatom-

containing polycarbosilanes as polycarbosilazanes [1], poly-

oxacarbosilanes [2] and polyborocarbosiloxanes [3] which are

available through conventional solution chemistry and are

useful as precursors of ceramics, glasses, high temperature

supports, insulation and wear protection materials.

It was recently shown that IR or UV laser irradiation of some

volatile organosilicon compounds in the absence or presence of

heteroatom-containing compounds allows for chemical vapor

deposition of polycarbosilanes [4], polyoxacarbosilanes [5],

polyborocarbosiloxanes [6] and polythiacarbosilanes [7] and

can serve as a simple, one-step alternative to the conventional

solution-involved syntheses.

Polycarbosilanes [4], polyoxacarbosilanes [5e] and poly-

thiacarbosilanes [7] were produced through IR or UV laser

irradiation of silacyclobutane or 1,3-disilacyclobutane (DSCB,

c-Si2C2H8) and of its mixtures with heteroatom-containing

* Corresponding author. Tel.: +420 2 20390308; fax: +420 2 20920661.

E-mail address: [email protected] (J. Pola).

0165-2370/$ – see front matter # 2005 Elsevier B.V. All rights reserved.

doi:10.1016/j.jaap.2005.10.007

volatile compounds. In these instances, the IR or UV laser-

induced formation of intermediate silene allows gas-phase

chemistry dominated by polymerization of silene, or controlled

by a sequence of (i) silene intercepting heteroatom-containing

species (O2, CS2) and (ii) polymerization of the fragments from

the unstable adduct. These processes lead to gas-phase

deposition of the polycarbosilanes and polyheterocarbosilane

thin films of ultrafine powders (Scheme 1).

It is known that UV laser photolysis [8] or IR laser

thermolysis [9] of gaseous dimethyl selenide (DMS, (CH3)2Se)

occurs as extrusion of Se atoms and formation of Se

agglomerates (of which Se2 and Se5 dominate in the gas phase

[10]) and that it affords chemical vapor deposition of thin films

of elemental Se. Should such reaction occur simultaneously

with the decomposition of 1,3-disilacyclobutane into silene, it

lends possibility for Sen interception by silene and hence

chemical vapor deposition of the yet unknown polyseleno-

carbosilane. No reaction between the Sen and silene species

would, on the other hand, result in chemical vapor deposition of

nanosized Se particles embedded in polycarbosilanes.

Both phenomena – the formation of polyselenocarbosilane

and that of Se/polycarbosilanes nanocomposite – are of interest

due to potential applications of these materials and due to

M. Santos et al. / J. Anal. Appl. Pyrolysis 76 (2006) 178–185 179

Scheme 1.

elucidation of the reaction between silene and Sen. We note that

the silene interception of many reagents is well known [11], but

that of Se has not been yet attempted.

We now report that IR laser irradiation of gaseous mixtures

of DSCB and DMS induces decomposition of both compounds,

involves interception of elemental Se by transient silene and is

an efficient way for the production of novel polyselenocarbo-

silanes that are unstable in atmosphere.

2. Experimental

The experiments were carried out using two different TEA

CO2 lasers. The CO2 Plovdiv University and a Lumonics K-103

lasers operated on the P(14) line of the 0001 ! 1000 transition

(949.48 cm�1) with a repetition frequency of 1 Hz and

respective energy 1 and 2 J in a pulse. For the irradiation of

gaseous DSCB–DMS mixtures in 140 and 95 ml Pyrex

reactors, the laser beam was focused by NaCl lenses to

achieve incident fluences of 4 and 50 J cm�2 (f.l. 15 cm) and

200 J cm�2 (f.l. 10 cm). The 140 ml Pyrex reactor (total

pressure of both reactants 13–28 mbar) consisted of two

orthogonal positioned Pyrex tubes (both 3 cm in diameter, one

9 cm and the other 13 cm long) fitted with KBr windows and it

was equipped with a sleeve with a rubber septum and PTFE

valve connecting it to a vacuum manifold. The 95 ml Pyrex

reactor (total pressure of both reactants 10 mbar) was a Pyrex

tube (3 cm in diameter, 10 cm long) furnished with NaCl

windows and a stopcock.

The progress of the decomposition of both compounds

was monitored by periodically removing the reactor and

placing it in the cell compartment of an FTIR spectrometer

(a Nicolet Impact or Perkin-Elmer 1600 spectrometer) using

absorption band of DSCB at 650 cm�1 and that of DMS at

1431 cm�1, and also by gas chromatography (a Shimadzu 14 B

chromatograph) and gas chromatography–mass spectroscopy

(a Shimadzu QP 5050 mass spectrometer) both using 25 m long

PoraBOND capillary column, programmed (30–160 8C) tem-

perature and sampling by a gas-tight syringe. These analyses

were conducted several minutes after the irradiation has been

ceased. This allowed the fog formed upon the irradiation descend

to the reactor bottom. The chromatograph was equipped with

flame-ionization detector and connected with a Shimadzu CR-

8A Chromatopac data processor. Decomposition products were

identified through their mass spectra using the NIST library.

The solid films were deposited from the gas phase on KBr,

Al and Au-plated Fe substrates accommodated in the reactors

before the irradiation.

The FTIR spectra of the films deposited on the KBr

substrates were measured directly in the reactor after

evacuation of gaseous products. The samples on Al and Au-

coated Fe substrates were transferred for the X-ray photoelec-

tron spectra (XPS) and electron microscopy measurements

using a double and single glove-box (argon inert gas) technique.

(The sample was transferred under argon to a sealed vial and

from it under argon to the XP spectrometer, or transferred under

argon to a sealed vial and exposed to air for 25 s and introduced

to an electron microscope.)

The XP spectra were measured using ESCA 310 (Gamma-

data Scienta) electron spectrometer. The pressure of residual

gases in the analyzer chamber during measurements was in the

low 10�9 mbar range. The spectra of Si (2p), C (1s), O (1s) and

Se (3d) and the spectra of Se L3M45M45 Auger electrons were

recorded. The curve fitting of the spectra was accomplished

using a Gaussian–Lorentzian line-shape. The decomposition of

Se (3d) profiles was made subject to the constraints of the

constant 3d5/2–3d3/2 doublet separation (0.9 eV) [12] and the

constant intensity ratio (3d5/2/3d3/2 = 1.45). Quantification of

the surface concentrations of elements was accomplished by

correcting the photoelectron peak areas for their cross-sections

[13].

Raman spectra of the samples exposed to air were measured

on a Renishaw RM2000 confocal micro-Raman spectrometer.

The excitation source was an Ar+ laser (514 nm); laser power

on the sample was kept at 0.2 mW. The scattered radiation from

the surface was collected in backscattering (1808) geometry at a

resolution of 4 cm�1.

M. Santos et al. / J. Anal. Appl. Pyrolysis 76 (2006) 178–185180

Fig. 1. Infrared spectra of DSCB and DMS (optical path, 10 cm; Me2Se,

13.3 mbar; DSCB, 1.3 mbar).

Table 1

Laser-induced decompositiona of DSCB and DMS in DSCB–DMS mixtures at

total pressure 10 mbar

Initial mixture (mbar) Depletion (in mol%)

DMS DSCB DMS DSCB

10 0 55

0 10 82

9 1 25 39

8 2 54 64

7 3 65 68

6 4 51 57

5 5 52 75

3 7 57 74

a 30 pulses, f = 120 J cm�2.

SEM photographs were obtained using a Philips XL30 CP

scanning electron microscope equipped with an energy

dispersive analyzer of X-ray radiation Edax DX4.

DMS (purity better than 98%) was purchased from Aldrich

and DSCB (purity better than 99%) was prepared in the lab

according to the earlier reported procedure [14].

Fig. 2. Depletion of DSCB (&) and DMS (^) upon irradiation with fluence of 200

and (c) DSCB (2 mbar)–DMS (8 mbar).

3. Results and discussion

The IR bands of DSCB (d(SiH2) mode [15]) and DMS

(rCH3 mode [16]) (overlapping in the region of the CO2 laser

emission (Fig. 1) allow infrared multiple-photon excitation of

both compounds.

3.1. Features of the DSCB–DMS co-decomposition

The irradiation of the gaseous DSCB–DMS mixtures (both

1–21 mbar) results in the decomposition of both educts and the

formation of gaseous products and a whitish fog depositing on

the reactor surface as whitish or orange films. The relative

depletion of DSCB and DMS depends on the initial ratio of

these educts. The illustrative examples are given in Fig. 2 and

Table 1.

The activation energy of the DSCB decomposition

(230 kJ mole�1 [17]) and the mean Se–C bond dissociation

energy (�250 kJ mole�1 [18]) are very similar, but the ground

state optical absorption coefficients (in cm�1 mbar�1) at

944 cm�1 for DSCB (1.5 � 10�2) and DMS (6.8 � 10�4)

significantly differ. These features are in keeping with more

mJ cm�2 of (a) DSCB–DMS (each 5 mbar), (b) DSCB (8 mbar)–DMS (2 mbar)


Fig. 3. Typical GC/MS trace of gaseous products of laser-induced co-decom-

position of DSCB and DMS: (1) CH4, (2) C2H2, (3) C2H4, (4) C2H6, (5) H2Se,

(6) CH3SiH3, (7) C3H6, (8) C3H6, (9) (CH3)2SiH2, (10) C4H4, (11) CH3SeH,

(12) (CH3)3SiH, (13) C4H8, (14) DMS, (15) DSCB, (16) CH3SeC2H5 and (17)

CSe2.

feasible IR multiple photon decomposition of DSCB. The

relative depletions of DSCB and DMS observed in different

mixtures (Fig. 2 and Table 1) reveal, however, that the

decomposition progress of each educt is enhanced at its higher

partial pressure. In other words, depletion of both educts (in

mol%) reaches very similar values independent of fluence and

the educts ratio. This observation is compatible with a collision-

assisted energy transfer between DSCB and DMS molecules,

bringing both DMS and DSCB molecules to a thermal

equilibrium.

The total distribution of the gaseous products (Fig. 3) is little

affected with the decomposition progress and depends to a

small extent on the initial educts ratio (Table 2).

The major products (in relative mol%) are methane (�52–

57), ethane (�3–22) and ethene (�14–28) which are

accompanied with very small quantities of ethyne, higher

hydrocarbons (C3H4, C4H4, C3H6 and C3H8), methylsilanes

((CH3)nSiH4 – n, n = 1–3) and Se-containing compounds

(CH3SeH, CH3SeC2H5, H2Se and CSe2). Very importantly,

(i) the total yields of methylsilanes correspond to less than 3%

of the DSCB decomposed, (ii) the total yield of methane, ethane

Table 2

Distribution of gaseous products in TEA CO2 laser co-decomposition of DSCB an

Initial mixture

(mbar)

Incident fluence

(J cm�2) (pulse no.)

Decomposition

progress (mol%)

Volatile productsa (rel

CH4 C2H2 C2H4

DSCB (3) 4 DSCB (52)

DMS (11) (70) DMS (38) 55.5 0.6 16

DSCB (7) 4 DSCB (43)

DMS (21) (40) DMS (35) 56.9 0 14.3

DSCB (3) 50 DSCB (53)

DMS (11) (100) DMS (37) 55.4 0 17.6

DSCB (21) 4 DSCB (38)

DMS (7) (50) DMS (35) 55.1 4.8 21.4

DSCB (13) 25 DSCB (29)

DMS (13) (40) DMS (28) 52.2 0 27.6

DSCB (13) 2 DSCB (30)

DMS (13) (40) DMS (27) 53.6 2.4 20.5

a Trace products: C3H4, C4H4, H2Se and CSe2.

and ethene correspond to more than 95% of the DMS

decomposed and (iii) the yield of methyl selenide corresponds

to less than 3% of the DMS decomposed.

Such distribution of volatile products is in line with

practically non-interacting, homogeneous decompositions of

DSCB and DMS. The CO2 laser-induced decomposition of

DSCB is known [19] to yield minute amounts of methane,

ethene, ethyne, propene and methylsilanes and large amounts of

a solid polycarbosilanes. It was accounted for [19] as

dominated by the formation of silene and its dehydrogenative

polymerization (DSCB ! 2H2Si CH2, polymerization, loss of

H2 ! polycarbosilane). The CO2 laser-induced decomposition

of DMS [20] yielding ethane, methane and ethene (the main

products) along with elemental selenium (main product) and

polyselenoformaldehyde (minor product) was explained [20] as

extrusion of selenium (and transient selenoformaldehyde)

through radical paths. The observed methylethyl selenide not

only confirms the occurrence of the previously reported radical

steps [20], but also proves a transient CH3Se radical [21] and its

reaction with C2H4 (produced upon decomposition of the

reported selenoformaldehyde [20]).

It thus appears that the only significant interference between

both decompositions consists of reactions between the species

producing the solid deposit, i.e. those between silene and

elemental selenium (a main route) and between silene and

selenoformaldehyde (a minor route). It is shown below that this

view is proved by the identification of the solid deposits.

3.2. Properties of solid deposits

The SEM analysis (Fig. 4) reveals that the deposited films

show, regardless of the irradiation conditions and the educts

ratio, a fluffy morphology consisting of irregularly shaped

agglomerates. These features were also observed with the

deposits from IR laser decomposition of DSCB alone [19] and

are very different from the round-shape and oval particles of

elemental selenium deposited by IR laser-induced decomposi-

tion of DMS [20].

d DMS

ative mol%)

C2H6 CH3SiH3 C3H6 C3H8 (CH3)2SiH2 CH3SeH (CH3)3SiH

21.5 0.20 0.40 0.80 0.50 0.10 0.10

21 0.40 0.40 2.2 1.30 2.10 0.40

21.7 0 0.5 0.6 0.40 3.7 0

3.2 6.2 0.20 0.40 6.30 0.40 1.60

7.9 2.1 0.3 0.7 3.5 3.5 1.7

8.8 2.9 0.3 0.8 4.6 3.2 2.3


Fig. 4. SEM images of solid deposit. Irradiation of (a, b) DSCB (21 mbar)–DMS (7 mbar) at 4 J cm�2, (c, d) DSCB (7 mbar)–DMS (21 mbar) at 50 J cm�2 and of (e,

f) DSCB–DMS (5 mbar each) at 200 J cm�2.

The XPS surface stoichiometry (of ca. 5 nm superficial

layers) calculated from intensities of photoemission lines

together with the bulk stoichiometry calculated from the EDX–

SEM analysis of several films deposited under different

conditions (Table 3) reveal similar compositions of these

films, i.e. similar amounts of Si and C, small amounts of Se and

significant contents of O. The incorporation of oxygen and the

small amounts of Se indicate that the films are extremely

sensitive to moisture and that they react with ubiquitous traces

of water directly in the reactor and/or with traces of atmosphere

upon transfer of the films from the reactor to the XP

spectrometer. The EDX-determined compositions of the films

exposed for 15 s and 1 h to atmosphere do not differ and they

Table 3

Core level binding energies (eV) and composition of some solid films deposited f

Initial mixture (mbar) Fluence (J cm�2) XPS analysis

DMS DSCB Stoichiometry

21 7 50 Si1.0 C1.04Se0.18O0.72

7 21 4 Si1.0 C0.86Se0.16O0.30

7 7 200 Si1.0 C0.87Se0.18O0.63

show lower content of Se and higher content of O. The reaction

of the films with traces of water is thus responsible for both

incorporation of O and a substantial removal of Se. The Se

observed by the EDX analysis corresponds to a form of Se not

reacting with water and is tentatively assigned to the elemental

form.

The high reactivity of the solid materials towards air

moisture was confirmed by the XP spectra (Table 3) and FTIR

spectra (Figs. 6 and 7) and also in additional experiments when

the films accumulated from several runs were exposed to air

and the volatile products formed were identified by GC and

GC–MS analysis [mass spectrum, m/z (relative intensity in

percent)] as H2Se [84 (13), 83 (6), 82 (86), 81 (31), 80 (100), 79

rom DSCB–DMS mixtures

EDX analysis

Si (2p) (eV)

(population, %)

Se (3d) (eV)

(population, %)

102.0 (74) 55.0 (44) Si1.0 C0.64Se0.03O1.39

103.5 (26) 56.1 (56)

102.0 (91) 55.1 (25) Si1.0 C1.05Se0.07O0.48

103.5 (9) 56.2 (75)

102.2 (74) 55.0 (22) Si1.0 C0.83Se0.09O1.46

103.6 (26) 56.1 (78)


Fig. 5. The fitted spectra of Se 3d spectra of the deposits obtained from

(a) DSCB (7 mbar)–DMS (21 mbar), (b) DSCB (21 mbar)–DMS (7 mbar)

and (c) DSCB–DMS (each 5 mbar) with corresponding fluence 50, 4 and

200 J cm�2.

Fig. 6. FTIR spectra of films deposited upon irradiation of (a) DSCB (7 mbar)–

DMS (21 mbar) ( f = 50 J cm�2) and (b) DSCB (21 mbar)–DMS (7 mbar)

( f = 4 J cm�2).

(28), 78 (50), 77 (16), 76 (15)] and CH3SeH [98 (17), 97 (8), 96

(100), 95 (51), 94 (65), 93 (77), 92 (41), 91 (33), 90 (15), 89 (9),

82 (9), 81 (19), 80 (52), 79 (9), 78 (28), 77 (12), 76 (11)]

compounds.

As to the XP spectra, that of Si 2p electrons is best fitted as

contributions of two components located at 102.2 and

103.5 eV which are, respectively, assignable [22,23]) to

RxSiOy (R Si, C; y = 2, 3) and SiO4 structures. The spectra

of Se 3d electrons are fitted as two components with Se 3d5/2peaks located at 55.0 � 0.2 and 56.1 � 0.2 eV. The Auger

parameter a (calculated as a sum of the binding energy of

Se 3d5/2 electrons and kinetic energy of corresponding Se

L3M45M45 (1G) Auger electrons amount to 1361.7 and

1360.2 eV. The values at 55 and 1361.7 eV correspond to

elemental selenium [24,25] and the values at 56.1 and

1360.2 eV are tentatively assigned to a polymer containing

Se–X (X = Si, C) bonds. The contributions of the Se 3d

electrons reveal that the elemental form is less abundant than

the Se in the Se–X bonds (Table 3 and Fig. 5) and that the

proportion of the Se–X form increases with increasing portion

of DSCB in the initial mixtures.

The presence of elemental selenium is also revealed by

Raman spectra measured after exposing the films to air, which

show a peak at 254 cm�1 (a-Se form, [26]) whose intensity is

more pronounced for deposits obtained from DSCB–DMS

mixtures with higher DMS content.

The FTIR spectra of the deposits show the typical pattern of

polycarbosilanes, and are very similar to those of the films

produced upon laser-induced decomposition of DSCB [19].

Those of the deposits obtained from the DSCB–DMS mixtures

rich in DSCB consist of strong bands at 780–845 cm�1, a weak

band at 1246–1250 cm�1, a medium band at 2127–2148 cm�1

and very weak bands between ca. 2860 and 2960 cm�1 which

are, in the given order, assignable [27] to n(Si–C) + r(CHx),

d(CHxSi), n(Si–H) and n(C–H) modes. The films deposited

from mixtures rich in DMS show also a band at 1048 cm�1 due

to n(SiOSi) mode and a very weak band at 615–625 cm�1, a

band at 953 cm�1 and a shoulder at 1262 cm�1 that are,

respectively, due to n(C–Se), r(CH3Se) and d(CH3Se) modes

[16]. The differences between the FTIR spectra obtained at the

different initial ratio of DMS and DSCB is illustrated in Fig. 6.

The selenium does not have active infrared modes and

stretching Si–Se modes [28] display themselves below

400 cm�1. The presence of the Si–Se bond is indirectly proved

by the shift of the n(Si–H) band which is located at 2148 cm�1

(deposits from DMS-rich mixtures) and 2127 cm�1 (deposits

from DSCB-rich mixtures). This change is compatible with

incorporation of electronegative Se (as Se–Si) inducing a shift

of the n(Si–H) band to higher wavenumbers [29]. Very high

sensitivity of the deposited films to atmosphere (illustrated on

Fig. 7) serves as another evidence for the formation of the Si–Se

bonds, since the enormous build-up of the n(SiOSi) absorption

band at 1070 cm�1 can only be explained by the well-known

[30] hydrolysis of the Si–Se bond to siloxane.

3.3. Gas-phase chemistry

The distribution of gaseous products strongly suggests that

homogeneous decompositions of DSCB and DMS take place


Scheme 2.

Scheme 3.

rather independently and that the extents of reaction steps of

CH3 radical formed from DMS are virtually the same as during

the decomposition of DMS itself. The practical non-inter-

ference of both decompositions (Scheme 2) leads to the

deposition of solid materials that can be described as a blend of

elemental Se and a polymer containing Si–Se and C–Se bonds.

The polymer materials are mostly formed by reactions of the

dominating species (silene and Sen molecules). We assume that

the Sen (mostly Se2) is incorporated in polymerizing silene

via Se-nucleophilic attack initiated 2 + 2 cycloaddition

and cleavage of the adduct into transient silaneselone and

selenoformaldehyde. The latter species are very reactive

Fig. 7. FTIR spectra of the film after its deposition (a) and exposure to air (b).

Conditions: DMS (21 mbar)–DSCB (7 mbar) ( f = 25 or 50 J cm�2).

and undergo polymerization producing polyselenocarbosilane

films (Scheme 2). Other minor steps, i.e. reaction of Se2 with the

less stable isomer of silene, methylsilylene and 1,2-dimethylsi-

lene (the dimethylsilylene dimer), as well as insertion of Se into

the Si–Si and Si–H bonds, are also feasible [31–34].

We stress that the increasing proportion of DSCB in the initial

DSCB–DMS mixtures is beneficial for production of higher

amounts of silene and hence for more efficient Sen interception,

leading to the formation of higher relative amounts of

polyselenocarbosilane compared to elemental selenium.

3.4. Hydrolysis of films

The contact of the deposited films to atmosphere leading to

the formation of volatile hydrogen selenide and methyl

selenide and resulting in the development of the Si–O–Si

bonds in the FTIR spectra (Fig. 7) is accounted for by the

reaction of the Si–Se bonds with air moisture [30]. The

formation of the H2Se and CH3SeH is in line with the presence

of the Si–Se–Si and Si–Se–CH3 structures in the deposited

solid (Scheme 3).

4. Conclusion

The TEACO2 laser irradiation into gaseous mixtures of 1,3-

disilacyclobutane and dimethyl selenide induces independent

decomposition of both compounds and affords chemical vapor

deposition of solid films which are a blend of elemental

selenium and a polymer whose structure is assessed as

polyselenocarbosilane.

The formation of these polymers takes place as reaction(s)

between the species which are dominating products of each

decomposition. These are silene and Sen molecules.

The described process is an extension of previous laser

induced decomposition of silacycles (silacyclobutane and


1,3-disilacyclobutane) with molecular oxygen [5e] and

carbon disulfide [7] and represents a new thermolytic pro-

cess by allowing reaction between thermally generated

transient and element, each of them being produced from the

decomposition of different precursor.

Polyselenocarbosilane films are unstable in atmosphere and

are readily hydrolyzed into polycarbosiloxanes and hydrogen

selenide and methyl selenide.

The low content of elemental Se determined after the

exposure of the polyselenocarbosilane films to air by the EDX

analysis is consistent with high ability of silene to intercept Sen

species.

The laser-induced co-decomposition of DSCB and DMS

represents the novel way for formation of Si–Se bond and

allows the deposition of novel selenocarbosilane polymer.

Acknowledgement

The work was supported by the Ministry of Education,

Youth and Sports of the Czech Republic (grant ME 684) and by

Spanish DGI, MCyT (BQU2003-08531-C02-02).

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IR laser-induced process for chemical vapor deposition of polyselenocarbosilane films

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Transcript of IR laser-induced process for chemical vapor deposition of polyselenocarbosilane films