Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 26: Quantum Wires: Transport Properties (organized by HL)

TT 26.2: Vortrag

Montag, 31. März 2014, 16:15–16:30, POT 006

In-situ x-ray diffraction during MBE growth of InAs nanowires on Si — •Andreas Biermanns¹, Anton Davydok¹, Emmanouil Dimakis^2,3, Masamitu Takahasi⁴, Takuo Sasaki⁴, Lutz Geelhaar², and Ullrich Pietsch¹ — ¹Universität Siegen, Festkörperphysik, Germany — ²Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany — ³Helmholtz-Zentrum Dresden-Rossendorf, Germany — ⁴Quantum Beam Science Directorate, Japan Atomic Energy Agency, Hyogo, Japan

Compared to the vapor-liquid-solid growth modes of group III-V semiconductor nanowires (NWs), e.g. Au-assisted growth or the self-assisted growth of GaAs NWs, it is a matter of intense debate whether or not liquid Indium is involved during the self-assisted growth of InAs NWs. Here, we present the results of an in-situ study of the nucleation phase of InAs NW growth on Si (111). X-ray scattering and diffraction methods have been employed during NW-growth at the synchrotron beamline 11XU at SPring-8 using a MBE chamber integrated with a surface diffractometer. The characteristic scattering signals from liquid In as well as the diffracted intensity of the crystalline NWs growing in the wurtzite (WZ) phase have been monitored during growth. We find that liquid In is present during the initial stage of growth, associated with the formation of extended WZ segments in the NWs. After the nucleation phase of the NWs, the liquid In vanishes, accompanied by a more defective crystal structure with a large number of stacking faults. The results are in accordance with a growth model, predicting a transition from locally In-rich to locally As rich conditions.