Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 44: ZnO and its relatives: Devices
HL 44.2: Talk
Tuesday, April 1, 2014, 11:00–11:15, POT 151
MOCVD-growth and characterisation of AZO-contacts for p-doped GaAs nanowire structures — •Christian Koppka1, Alexander Koch1, Andreas Nägelein1, Sana Muhammad Ullah1, Matthias Steidl1, Katja Tonisch1, Peter Kleinschmidt1,2, Sabine Nieland2, Uta Stürzebecher2, Claudia Schmidt3, Werner Prost3, and Thomas Hannappel1,2 — 1TU Ilmenau, Germany — 2CiS Forschungsinstitut, Erfurt, Germany — 3Universität Duisburg-Essen, Germany
A key part in the development of nanowire-based solar cells is based on the production of appropriate front side contacts. In this regard, the application of transparent conductive oxides (TCOs) for the production of tunnel junctions on p-doped III-V semiconductors is investigated. To obtain homogeneous coating of non-planar surfaces, such as core-shell nanowire structures, an ALD type process has been established in a standard MOCVD reactor (Aixtron). Deposition parameters such as growth temperature, carrier gas flow and percursor concentrations were adjusted using planar sapphire and p-GaAs substrates in a first step to achieve highly conductive and transparent films. The deposited films were characterized by scanning electron micrsocopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) as well as various methods for determining the optical and electrical properties. Current-voltage measurements reveal an ohmic behaviour of the AZO contact on planar p-doped GaAs. In a next step, this contact system is implemented on nanowire structures.