An electron energy loss spectroscopy study of the conductivity of polar ZnO surfaces

The surface conductivity of the polar ZnO faces was changed by exposure to H and O₂, by Ar ion bombardment and by heat treatments. Simultaneous studies of the corresponding Electron Energy Loss Spectra in the range 3–20 eV surprisingly indicated that the lowest energy state, at 3 eV, was not involved in these conductivity changes. The only states that could be involved were at 5.3 and 14.3 eV.