Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties
HL 91.7: Poster
Donnerstag, 14. März 2013, 16:00–20:00, Poster A
Compressive strain in MBE grown GaAs nanowires induced by an Al2O3 shell prepared by atomic layer deposition — •Torsten Jörres1,2, Torsten Rieger1,2, Andreas Biermanns3, Ullrich Pietsch3, Detlev Grützmacher1,2, and Mihail Ion Lepsa1,2 — 1Peter Grünberg Institut - 9, Forschungszentrum Jülich, 52425 Jülich, Germany — 2JARA-Fundamentals of Future Information Technology — 3Universität Siegen, Festkörperphysik, Walter-Flex-Str. 3, 57072 Siegen, Germany
In the processing of nanowire (NW) based electronic devices, high-κ dielectrics are used to passivate the surface or as gate oxides for field effect transistor applications. In this sense, Al2O3 films prepared by atomic layer deposition (ALD) represent an alternative because it allows a precise control of the layer thickness and dielectric properties by choosing appropriate deposition conditions. However, at such a scale, any difference in thermal expansion coefficients might induce strain in the NW and therefore affect their electronic properties. Here, we show recent results on MBE grown GaAs NWs with diameter of 75 nm encapsulated in a 30 nm thick Al2O3 shell. High resolution XRD measurements were performed at the P08 beamline at the PETRA III synchrotron in Hamburg in order to measure the shell-induced strain in the NWs. A small, but measurable compressive strain in the GaAs NWs of 0.05% was observed. High resolution transmission electron microscopy images of these nanowires show the conformal deposition of the Al2O3 shell as well as a very small roughness.