Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 46: III-V semiconductors: mainly wires and dots
HL 46.4: Vortrag
Dienstag, 12. März 2013, 15:45–16:00, H15
The investigation of alloy formation during InAs nanowires growth on GaAs (111)B substrate — •Muhammad Saqib1, Andreas Biermanns1, Anton Davydok1, Torsten Rieger2, Thomas Grap2, Mihail Lepsa2, and Ullrich Pietsch1 — 1Feströphysik, Universität Siegen, Walter-Flex-Str. 3, Siegen 57072, Germany — 2Peter Grünberg Institute (PGI-9), Forschungzentrum Jülich, Jülich 52425, Germany
A possible way to obtain nanowires is the growth in molecular beam epitaxy (MBE) on the (111) oriented surface of the desired substrate, covered by a thin oxide layer. A crucial parameter in this method is the initial thickness of the oxide layer, often determined by an etching procedure. In this contribution, we report on the structural investigation of two different series (etched and unetched) of NWs samples. Vertically aligned InAs nanowires (NWs) doped with Si were self-assisted grown by molecular beam epitaxy on GaAs [111]B substrates covered with a thin SiOx layer. Using a combination of symmetric and asymmetric X-ray diffraction we study the influence of Si supply on the growth process and nanostructure formation. We find that the number of parasitic crystallites grown between the NWs increases with increasing Si flux. In addition, we observe the formation of a Ga0.2In0.8As alloy if the growth is performed on samples covered by a defective (etched) oxide layer. This alloy formation is observed within the crystallites and not within the nanowires. The Gallium concentration is determined from the lattice mismatch of the crystallites relative to the InAs nanowires. No alloy formation is found for samples with faultless oxide layers.