Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 43: Poster Session: Quantum Dots and Wires - Preparation and Characterization / Devices (incl. Laser) / Ultrafast Phenomena
HL 43.2: Poster
Tuesday, March 27, 2012, 09:30–12:30, Poster D
Investigation of single GaAs nanowires through grazing incidence X-ray diffraction — •Genziana Bussone1,2, Rüdiger Schott3, Anton Davydok1, Andreas Biermanns1, Dirk Reuter3, Andreas D. Wieck3, and Ullrich Pietsch1 — 1Universität Siegen, Festkörperphysik, Germany — 2European Synchrotron Radiation Facility, Grenoble, France — 3Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Germany
Semiconductor nanowires (NWs) are a promising route for the conception of advanced electronic and photonic devices. For these purposes, absence of defects and homogeneity of the crystal lattice are crucial along the entire NW. Here, we report on the characterization of freestanding GaAs NWs using X-ray diffraction with a nanometer-sized X-ray beam, allowing to probe the crystal structure along the wire. GaAs NWs have been grown on a (111)-oriented GaAs substrate by molecular beam epitaxy using the gold-assisted growth mode. The position of the NWs was controlled by a direct implantation of Au using a focused ion beam system followed by an annealing procedure, which allows to precisely locate single NWs. The controlled arrangement and the nano-focus setup of beamline ID01 at the ESRF allowed the investigation of single, freestanding NWs in a grazing incidence geometry in order to probe the inplane-lattice parameter of the NWs. For random grown NWs, this is not possible due to the large footprint of the X-ray beam. Radial scans were performed at different heights along the NW. The data show a relaxation of the crystal lattice along the wire, revealed by the increasing of the lattice spacing closer to its top.