Dresden 2011 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 17: Crystallography in Materials Science (Joint Session of KR, DF)
DF 17.1: Invited Talk
Thursday, March 17, 2011, 14:00–14:45, HSZ 101
Crystallography of Nanowires — •Julian Stangl1, Dominik Kriegner1, Christian Panse2, Bernhard Mandl1,3, Kimberley A Dick3, Mario Keplinger1, Johan M Persson4, Philippe Caroff3,5, Daniele Ercolani6, Lucia Sorba6, Friedhelm Bechstedt2, and Günther Bauer1 — 1Johannes Kepler University Linz, Austria — 2Friedrich-Schiller-Universität Jena, Germany — 3Lund University, Sweden — 4Technical University of Denmark — 5IEMN, UMR CNRS, France — 6Scuola Normale Superiore Pisa, Italy
Semiconductor nanowires are interesting not only from physical and technological viewpoints, but also in a crystallographic sense. While most III-V semiconductors, except nitrides, crystallize exclusively in the cubic zinc-blende lattice in bulk or epitaxial layers, in nanowires very often hexagonal modifications such as wurtzite, but also the more complex 4H structure are observed. The wires grow mainly along the cubic <111> directions, where those lattice structures on first sight differ only by the stacking sequence of bilayers, changing from fcc to hcp. Detailed x-ray diffraction investigations for InAs and InSb nanowires reveal, however, that beside the stacking sequence also the atomic distances change, so that the unit cells deform compared what would be expected from a simple change of stacking. Comparisons to density functional theory calculations are in excellent agreement with the experimental data, and the combination of x-ray diffraction and theoretical calculations allow explaining the reason for the observed changes in atomic distances.