Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 33: Poster Session III

HL 33.25: Poster

Mittwoch, 14. März 2018, 17:30–19:30, Poster F

Rotational twins in III-V/Si(111) virtual substrates and their impact on subsequent III-V nanowire growth — •Matthias Steidl¹, Christian Koppka¹, Lars Winterfeld², Marsel Karmo², Katharina Peh¹, Oliver Supplie¹, Peter Kleinschmidt¹, Erich Runge², and Thomas Hannappel¹ — ¹Photovoltaics Group, Institute of Physics, Technische Universität Ilmenau, 98693 Ilmenau, Germany — ²Theoretical Physics I, Institute of Physics, Technische Universität Ilmenau, 98693 Ilmenau, Germany

The epitaxial integration of III-V nanowires (NWs) with Si combines the tunable, high-performance properties of III-V materials with the well-established Si technology. In particular the combination of (111) oriented epilayers/transition layers with the vapor-liquid-solid (VLS) growth of doped, NW-based III-V structures is a subject of intense research. However, the epitaxy on (111) orientation is generally accompanied by the formation of rotational twins. In the present study, we thoroughly investigate the twin suppression in GaP/Si(111) virtual substrates below 5 vol%. In particular, the misorientation of the vicinal Si substrate has a crucial influence on the resulting twin density. We explain the underlying mechanism by a DFT and KMC based nucleation model and show the impact of rotational twin boundaries (RTBs) in GaP/Si on the subsequent NW growth both for GaP and GaAs NWs. RTBs can suppress NW growth entirely or lead to different undesired growth directions, such as horizontal and diagonal growth. To explain the similarities and differences of GaP and GaAs NW growth, we developed a second model based on classical nucleation theory.