Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 30: Nano Wires: Growth and Characterization

HL 30.2: Talk

Tuesday, March 15, 2011, 10:30–10:45, FOE Anorg

MBE growth of axial AlGaAs/GaAs heterostructure nanowires — •Torsten Rieger, Mihail Ion Lepsa, Thomas Schäpers, Hans Lüth, and Detlev Grützmacher — Institute of Bio- and Nanosystems (IBN-1) and JARAFundamentals of Future Information Technology, Forschungszentrum Jülich GmbH, D-52425 Jülich

Nanowire (NW) heterostructures are promising candidates for future (opto-)electronic devices but only little is known about their growth, especially in the case of axial heterostructures containing different group III elements. Here we report about the molecular beam epitaxial (MBE) growth of axial AlGaAs/GaAs heterostructure NWs on GaAs (111)B substrates spin-coated with a thin layer of hydrogen silesquioxan (HSQ). No Au is used to catalyze the growth. We have investigated the influence of Al beam flux, growth time and substrate temperature on the NW growth. It is found that even small amounts of Al reduce the axial growth but strongly promote growth on the amorphous oxide and NW sidewalls leading to unintentionally grown core/shell NWs. Up to an Al amount corresponding to 20%, the axial growth rate is still higher than the layer growth rate. This demonstrates the possibility to grow axial AlGaAs/GaAs heterostructure nanowires using self-catalyzed growth, although the switching back from AlGaAs to GaAs is found to be challenging, mainly due to growth on the amorphous oxide.