ELECTRONIC CHARACTERIZATION OF ZNO/CUO HETEROJUNCTIONS

CuO/ZnO heterocontacts have previously been reported to exhibit nonlinear I-V characteristics which are sensitive to their environment including reducing gases and humidity. A detailed understanding of these phenomena are, however, not yet available, especially in terms of the electronic structure of the heterojunction. In this study, more reproducible methods for preparing p-CuO/n-ZnO heterojunction devices are attempted following thin-film techniques. The properties of CuO/ZnO heterojunctions prepared by reactive sputter deposition are being investigated taking into account oxygen stoichiometry, film thickness and morphology. D.c. and a.c. impedance measurements performed as a function of temperature and atmosphere are used to examine modifications in the junction's barrier characteristics. A model for the electronic structure of the CuO/ZnO heterojunction and its reported sensitivity to its environment is being developed on this basis.