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O: Fachverband Oberflächenphysik

O 73: Nanostructures at Surfaces: Metals, Oxides and Semiconductors III

O 73.1: Vortrag

Mittwoch, 22. März 2017, 10:30–10:45, REC/PHY C213

Formation of GaP rotational twins at the interface to Si(111) — •Lars Winterfeld, Christian Koppka, Thomas Hannappel, and Erich Runge — Institut für Physik, Technische Universität Ilmenau, 98693 Ilmenau, Germany

We present DFT and Kinetic Monte Carlo results concerning the formation of rotational twins domains (RTDs) of GaP on Si(111). Gallium phosphate is used as a buffer layer on silicon for the growth of III-V nanowires (NWs) on top. Here, (111)-oriented substrates are commonly used, as NWs preferably grow in [111] direction and NWs vertical to the substrate are advantageous for most device architectures. Heteroepitaxial layer growth on Si(111), however, is almost always accompanied by the occurrence of RTDs, which is a crystal defect having detrimental effects on NW growth and therefore on optoelectronical properties. Recently, Koppka et al.[1] could experimentally show that adjusting the growth conditions (temperature, V/III ratio, miscut angle of the substrate, etc.) can tremendously suppress the formation of RTDs to less than 5 vol%. In this talk, we aim for an ab initio understanding of the underlying atomic mechanisms.

[1] C. Koppka et al., Crystal Growth & Design 2016 (doi: 10.1021/acs.cgd.6b00541).