ELECTRONIC-STRUCTURE INVESTIGATION AT A ZIRCONIA NICKEL INTERFACE

X-ray photoelectron spectroscopy (XPS) is used to study electronic structure effects at a zirconia-nickel interface. A method is described to fabricate ZrO2 coatings on metallic substrates under ultrahigh vacuum conditions with a sufficiently low coverage to allow examination of the interfacial region. Charging effects which relate to the size of oxide particles deposited on the metal (and not to accumulated charge on the oxide) have been identified for small ZrO2 particles on nickel, palladium and NiO substrates equivalent to a coating approximately 6 angstrom thick. The charging effects show up as a broadening of the XPS Zr 3d core-level spectrum. By examining the XPS Ni 2p3/2 and XPS valence band spectra it is found that an oxidized nickel surface layer is reduced during ZrO2 deposition.