Surface and electrical studies of CuO:V2O5 thin films

Abstract

Results from the studies of multicomponent CuO:V2O5 bulk material and thermally evaporated thin films of highly conducting bulk composition prepared at different substrate temperatures are thus compared and discussed. The electronic conductivity is enhanced on increase in the substrate temperature Ts and reaches a maximum value of 12.3 × 10-6Ω-1 cm-1 for Ts = 423 K. X-ray photoelectron spectroscopy studies indicate an increase in the reduced states of vanadium and copper ions in going from the bulk glass to the thin film. Dynamic secondary-ion mass spectroscopy studies on thin films over a depth of 3000 Å show a strong dependence of Ts on the Cu-to-V intensity ratio. Even though stoichiometric values for thin films are achievable by varying the Ts, the oxidation states of Cu in these films are predominantly monovalent. The electrical behaviors of these materials and their thin film counterparts are finally being discussed in relation to the surface analysis data. © 1995.