1 nm

GaSe

GaAs

Bi2Te3

Bi2Te3

More to read in physica status solidi (rrl)

Liang He, Xufeng Kou, and Kang L. Wang Review of 3D topological insulator thin-film growth by molecular beam epitaxy and potential applications [Review @ RRL] Phys. Status Solidi RRL 7(1–2), 50–63 (2013), DOI 10.1002/pssr.201307003 The discovery of topological insulators (TI) has generated strong activities in condensed matter physics since recent years. In this review, the authors represent the use of molecular beam epitaxy (MBE) technique to achieve high quality TI materials with few bulk defects and large surface contribution. Furthermore, the mechanisms to construct TI-related heterostructures and superlattices for both fundamental studies and applications is investigated.

Binghai Yan, Delin Zhang, and Claudia Felser Topological surface states of Bi2Se3 coexisting with Se vacancies [Rapid Research Letter] Phys. Status Solidi RRL 7(1–2), 148–150 (2013), DOI 10.1002/pssr.201206415 Topological surface states are known to be robust against local defects such as vacancies and dangling bonds. In this Letter, another aspect of the topological protection is demonstrated. On the Bi2Se3 surface, topological surface states are found to sink down from the outer surface to the inner atomic layers, separating themselves away from defects, if a large number of Se vacancies exists on the surface.

A. Janotti, C. Franchini, J. B. Varley, G. Kresse, and C. G. Van de Walle Dual behavior of excess electrons in rutile TiO2 [Rapid Research Letter] Phys. Status Solidi RRL 7(3), 199–203 (2013), DOI 10.1002/pssr.201206464 First-principles calculations reveal that localized small polarons and delocalized free electrons coexist in TiO2, with polarons being slightly lower in energy. This explains why electronic transport measurements probe mobile, delocalized free electrons, while optical absorption spectra provide signatures of small polarons. Binding of polarons to shallow donors such as oxygen vacancies explains the rich spectrum of Ti3+ species observed in electron spin resonance experiments.

Heiko Frenzel, Alexander Lajn, and Marius Grundmann One decade of fully transparent oxide thin-film transistors: fabrication, performance and stability [Review @ RRL] Phys. Status Solidi RRL 7(9), 605–615 (2013), DOI 10.1002/pssr.201307259 Fully transparent oxide thin-film transistors celebrate their 10th anniversary. Since the beginnings, using crystalline channel layers, there have been manifold improvements in terms of device performance and stability under stress. Today, mostly low-temperature grown amorphous channel layers are used. However, dielectrics are still fabricated by sophisticated techniques to suppress leakage currents. Metal–semiconductor field-effect transistors based on transparent rectifying contacts as gate electrode represent a promising alternative technology for transparent electronics.

Anke Laemmle, Roland Wuerz, and Michael Powalla Efficiency enhancement of Cu(In,Ga)Se2 thin-film solar cells by a post-deposition treatment with potassium fluoride [rrl solar] Phys. Status Solidi RRL 7(9), 631– (2013), DOI 10.1002/pssr.201307238 Alkali-free Cu(In,Ga)Se2 (CIGS) absorbers were doped with potassium (K) after CIGS growth by a post-deposition treatment (PDT). The addition of K to the absorber leads to a strong increase in cell efficiency from 10.0% for the K-free cell to 14.2% for the K-doped cell, mainly driven by an increase in the open-circuit voltage Voc and the fill factor FF.

Alexander J. Marsden, Maria-Carmen Asensio, José Avila, Pavel Dudin, Alexei Barinov, Paolo Moras, Polina M. Sheverdyaeva, Thomas W. White, Ian Maskery, Giovanni Costantini, Neil R. Wilson, and Gavin R. Bell Is graphene on copper doped? [Rapid Research Letter] Phys. Status Solidi RRL 7(9), 643–646 (2013), DOI 10.1002/pssr.201307224 Using nano-spot angle-resolved photoemission spectroscopy (ARPES) it is shown that graphene grown on low-cost copper foil is undoped with an ideal gapless band structure, even after air exposure. The figure shows nano-ARPES of a Dirac cone “slice” after annealing in vacuum. At 200 °C the band structure is that of pristine undoped graphene. However, annealing to 500 °C induces a gap and doping, and the authors explore the possible mechanisms.

A. Mazid Munshi and Helge Weman Advances in semiconductor nanowire growth on graphene [Review @ RRL] Phys. Status Solidi RRL 7(10), 713–726 (2013), DOI 10.1002/pssr.201308010 Epitaxial growth of semiconductor nanowires on graphene is an emerging research field for the development of next-generation flexible electronic and optoelectronic hybrid devices. This article reviews the recent developments in the growth of various semiconductor nanowires and the device applications of the nanowire/graphene hybrid systems.

Azam Khan, Mazhar Ali Abbasi, Jonas Wissting, Omer Nur, and Magnus Willander Harvesting piezoelectric potential from zinc oxide nanoflowers grown on textile fabric substrate [Rapid Research Letter] Phys. Status Solidi RRL 7(11), 980–984 (2013), DOI 10.1002/pssr.201308105 The fabrication of novel devices for harvesting the energy is of high interest due to the shortage of energy resources. At present, the use of flexible and nonconventional substrates for the fabrication of nanogenerator devices using ZnO nanostructures is more popular among the scientific community. The present Letter demonstrates the development of piezoelectric nanogenerator based on ZnO nanoflowers with improved performance.