Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 13: Focus Session: Functional Semiconductor Nanowires I (organized by HL)
TT 13.11: Vortrag
Montag, 16. März 2015, 12:45–13:00, EW 201
synchrotron X-ray photoelectron spectroscopy study of GaAs/InAs core/shell nanowires grown by MBE — •behnam khanbabaee1, torsten rieger2, nataliya demarina2, detlev grützmacher2, mihail Ion lepsa2, rainer timm3, and ullrich pietsch1 — 1Solid State Physics, Dept. of Physics, University of Siegen, Siegen, Germany — 2Peter Grünberg Institute and JARA-FIT, Forschungszentrum Jülich GmbH, Jülich, Germany — 3Synchrotron Radiation Research and The Nanometer Structure Consortium, Dept. of Physics, Lund University, Lund, Sweden
Semiconductor nanowire (NW) heterostructures are promising building blocks for future electronic devices. In particular, GaAs/InAs radial NWs heterostructures are candidates for nano-electronics, where a lower band gap semiconductor, e.g. InAs, is grown on a semiconductor with a higher band gap, e.g. GaAs, providing band bending at the interface. For effective band confinement it is necessary to control the radial thickness, and the local defect structure at the hetero-interface and its relation to the electronic properties. Here we report on X-ray photoelectron spectroscopy of GaAs/InAs core/shell NWs grown by molecular beam epitaxy. After cleaning under atomic hydrogen the As-oxides on top of the NWs were considerably reduced while the Ga- and In-oxides were slightly reduced. The binding energy of the As 3d core levels was shifted about 1 eV towards lower energies. These results show that the As component of the native oxide turns the NWs surface strongly n-type. Our findings show that the shelling of GaAs NWs with InAs may leads to band bending of 0.2 to 0.3 eV at hetero-interface.