Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.23: Poster

Dienstag, 15. März 2011, 18:00–21:00, P3

Electronic structure of III-V hexagonal polytypes — •Christian Panse and Friedhelm Bechstedt — Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Germany

Semiconducting nanowires (NW) are of great interest due to their potential in electronic and optoelectronic applications. With increasing success on the control over the crystal structure in the last years it became possible to grow pure layers of zinc blende (ZB/3C), wurtzite (WZ/2H) and also small segments of the hexagonal 4H polytype. As this offers a new degree of freedom for NW device design, investigations of the electronic properties of different hexagonal polytypes are needed for the design of polytypic superlattice nanowire devices.

We perform ab-initio calculations within the density functional theory (DFT) and discuss the results on the electronic and optical properties of III-V compounds (GaAs, InAs, InP, InSb) with respect to the different WZ/ZB stacking sequences. The bulk phases of different polytype structures (3C, 2H, 4H, 6H) are especially studied. The electronic properties are calculated versus the hexagonality of the polytypes using the LDA-1/2 method, even including spin-orbit coupling, which leads to quasiparticle band structures but with the effort of conventional DFT. We present results on effective masses, fundamental gaps, spin-orbit and crystal-field splittings and band discontinuities and how these band parameters are modified by the polytypism. Special attention is given to the impact of the cell internal structure.