Superlattices and Microstructures volume 39, issue 1-4, P8-16 2006 DOI: 10.1016/j.spmi.2005.08.056 View full text
Oliver Schmidt, Arnd Geis, Peter Kiesel, Chris. G. Van de Walle, Noble M. Johnson, Andrey Bakin, Andreas Waag, Gottfried H. Döhler

Abstract: AbstractThe electrical properties of high-resistivity zinc oxide (ZnO) bulk and epi-samples are strongly influenced by the sample ambient. Bulk samples that are highly resistive in ambient air can be reversibly transformed into a high conducting state under vacuum. As an explanation we suggest a conducting electron channel at the ZnO surface. Under vacuum this channel appears upon annealing. Exposure to ambient air destroys the channel. The channel is evident only for samples showing a high bulk resistivity, …

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