XPS investigations of the reactivities of oxidized ZrNb interfaces formed by deposition on a gold substrate

The interaction of a film of Zr (∼ 38 Å thick) deposited under ultrahigh vacuum (UHV) on to an approximately 12 Å film of NbO on a gold substrate has been studied with X-ray photoelectron spectroscopy (XPS). Evidence is presented for an interfacial conversion from Zr and NbO to ZrO2 and Nb. The reactivity of this sample was studied through a series of sequential treatments. Although changes occur in the topmost layer, the ZrNb interfacial region, as identified by a shoulder at ∼ 180 eV in Zr 3d and the 203.0 eV peak in Nb 3d, appears to be remarkably inert on heating at 300°C under UHV, as well as on subjecting to O2 and hydrogen plasma treatments.