Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 24: Poster Session: Ge/Si/SiC / III - V Semiconductors

HL 24.8: Poster

Montag, 26. März 2012, 16:00–19:00, Poster D

Band alignment between III-V polytypes — •abderrezak belabbes, Christian Panse, Jürgen Furthmüller, and Friedhelm Bechstedt — Friedrich-Schiller-Universität Jena Max-Wien-Platz 1 D-07743 Jena

Growth of III-V nanorods leads to several stackings and hence besides of 2H also to the formation of other polytypes (4H and 6H). The hexagonal polytypes 2H, 4H, and 6H give rise to a drastic changes of the bonding topology along the cubic [111] or hexagonal [0001] axis but also to significant changes of the electronic structure, e.g. the fundamental energy gap, with respect that of the cubic 3C polytype. Heterocrystalline but homomaterial junctions appear. The trials toward their understanding by means of almost first-principles calculations were basically restricted to the junction 3C-2H and the density functional theory (DFT) which however significantly underestimates the fundamental gaps. In this study, the electronic structure for a variety of polytypes of the Ga-V and In-V compounds (V = P, As, Sb) is computed using a recently developed approximate calculation scheme, the LDA-1/2 method, and taking into account the spin-orbit interaction. Clear trends for the resulting band gaps and band orderings are observed. The aligned electronic structures are used to explain properties of junctions between two polytypes. The gaps and offsets allow to discuss spectroscopic results found recently for such III-V nanowires.