Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 72: Quantum wires

HL 72.2: Talk

Thursday, March 19, 2015, 10:30–10:45, EW 203

Electrical properties of freestanding GaAs nanowires investigated by a multi-tip STM — •Matthias Steidl¹, Stefan Korte², Weihong Zhao¹, Hubertus Junker², Werner Prost³, Vasily Cherepanov², Bert Voigtländer², Peter Kleinschmidt¹, and Thomas Hannappel¹ — ¹Photovoltaics Group, Institute for Physics, Technische Universität Ilmenau, D-98684 Ilmenau — ²Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, D-52425 Jülich and JARA-Fundamentals of Future Information Technology — ³CeNIDE and Center for Semiconductor Technology and Optoelectronics, University of Duisburg-Essen, D-47057 Duisburg

We have grown undoped and p-type Zn-doped GaAs-Nanowires (NW) on GaP(111)B using the Au-assisted vapor-liquid-solid growth mode in a metal-organic vapor phase apparatus with different growth procedures. For the electrical characterization we applied a multitip STM as a nanoprober and conducted four-point probe measurements on single free-standing NWs. The doped NWs show highly non-linear I-V curves with diode like behavior. This reveals the existence of a space charge region along the NW axis, which we attribute to variations in the doping concentration. Furthermore, spatially resolved measurements of electron beam induced current (EBIC) indicate the width and localization of this space charge region. These measurements reveal that both the resistivity and the localization of the space charge region is dependent on the growth condition.