Oxygen adsorption on Cu/ZnO(0001)-Zn

P. Lazcano, M. Batzill, U. Diebold, P. Häberle

Departamento de Física, Pontificia Universidad Católica de Valparaíso, 2950 Valparaíso, Chile
Departamento de Física, Universidad Técnica Federico Santa María, 1680 Valparaíso, Chile
Department of Physics, PHY 114, University of South Florida, Tampa, Florida 33620-5700, U.S.A.
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, U.S.A.
Department of Physics, Tulane University, New Orleans, Louisiana 70118, U.S.A.

Phys. Rev. B 77 (2008) 035435

We hereby describe the modifications induced in a Cu thin film induced by different oxidation processes. By using plasma assisted deposition, we have adsorbed oxygen onto the Cu/ZnO(0001)-Zn surface. Cu was deposited on the sputtered-annealed ZnO substrate at room temperature, which was later exposed to oxygen. Using x-ray photoelectron spectroscopy, we verified the effect of the surface treatment on the electronic structure. Our findings are consistent with a partially oxidized Cu layer, with the CuO located at the interface between ZnO and the adsorbed Cu islands. Further Cu deposition induces the formation of Cu2O as judged by the evolution of the spectra. Annealing the sample up to 750 °C in UHV induces further reduction of the oxide, metallic Cu is recovered on the top layer, with evidence of Cu desorption into the vacuum or incorporation into the substrate.

Reprints available from U. Diebold (diebold at iap_tuwien_ac_at).

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