Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 62: Quantum Dots and Wires: Transport Properties I (mainly Quantum Wires)

HL 62.7: Talk

Wednesday, March 28, 2012, 16:30–16:45, EW 203

Four-point electrical characterization and gas sensing properties of CuO nanowire devices — •Stephan Steinhauer, Elise Brunet, Giorgio Cataldo Mutinati, and Anton Köck — Health & Environment Department, Molecular Diagnostics, AIT Austrian Institute of Technology GmbH, 1220 Vienna, Austria

Metal oxide nanowires have recently attracted much attention as they may be used in numerous potential applications, especially in highly sensitive gas detecting devices. Unlike other metal oxides, cupric oxide (CuO) is known as a p-type semiconductor with a narrow band gap around 1.2eV. In order to gain a better understanding of CuO nanowire transport properties, we characterize them in a four-point configuration and investigate the influence of the surrounding gas atmosphere.

CuO nanowires are synthesized by thermal oxidation of resistively heated Cu wires at ambient conditions. By this method, CuO nanowires with lengths up to 100 micrometer and typical diameters between 30 and 150 nanometer can be fabricated. After the transfer to silicon substrates, single CuO nanowires are contacted in a four-point configuration by optical and electron beam lithography using a metal lift-off process. The temperature dependence of nanowire transport properties is investigated in four-point and two-point measurements in order to evaluate specific conductance and contact resistance. When operated as conductometric gas sensors, CuO nanowires show a strong interaction with the surrounding gas due to the high surface to volume ratio and are able to detect very small concentrations of the toxic gases CO and H2S in the low ppm range.