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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.39: Poster
Donnerstag, 17. März 2011, 18:00–21:00, P4
Preparation of quantum transport in GaAs/AlGaAs core/shell nanowires — •Pascal Heintzmann, Stephan Wirths, Christian Blömers, Karl Weis, Kamil Sladek, Andreas Penz, Hilde Hardtdegen, Stefan Trellenkamp, Thomas Schäpers, and Detlef Grützmacher — Institut für Bio- und Nanosysteme (IBN-1), Forschungszentrum Jülich, 52425 Jülich, Germany
One of the key advantages of the growth of self assembled nanowires is the possibility to fabricate axial and radial heterostructures in a single growth step. Here we focus on GaAs/AlGaAs core/shell structures in order to achieve one-dimensional electron confinement in the GaAs core. These core/shell heterostructure nanowires are promising for improved electron mobility due to reduced surface impurity scattering.
The GaAs/AlGaAs nanowires used for our investigations were grown by selective area metal organic vapor phase epitaxy on a GaAs (111) substrate. Our wires consist of a GaAs core surrounded by an intrinsic AlGaAs layer, an n-doped AlGaAs layer, an intrinsic AlGaAs layer and finally a thin GaAs cap layer. For electrical characterization the wires were removed mechanically from the original substrate and subsequently placed on a prepattered SiO2-covered Si (100) substrate. Each wire was contacted individually with Ni/AuGe/Ni/Au electrodes using electron beam lithography. In order to optimize the contact resistance the nanowires were annealed in a rapid thermal processing furnace for different times and temperatures. By performing 2-terminal and 4-terminal transport measurements information on the contact resistance and nanowire conductivity is obtained.