Evidence for the instability of surface oxygen at the Zn(0001)-O-Cu interface from core-level and X-ray induced Auger spectroscopies

By monitoring the O(1s) and Zn(LMM) Auger spectra it has been shown that the deposition of copper atoms at a Zn(0001)-O overlayer results in the desorption of oxygen with simultaneous reduction of Zn2+ to Zn-0 at 300 K. The surface concentrations of oxygen and copper adatoms are calculated from the O(1s) and Cu(2p) intensities while the X-ray induced Auger Zn(LMM) transition provides evidence for Zn2+ and its reduction to Zn-0. The driving force for oxygen desorption is suggested to arise from the formation of a copper-zinc intermetallic brass-like overlayer which has little affinity for oxygen.