Surface and electrical studies of CuO:V 2O 5 thin films

Abstract

Results from the studies of multicomponent CuO:V 2O 5 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 T s and reaches a maximum value of 12.3 × 10 −6Ω −1 cm −1 for T s = 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 T s on the Cu-to-V intensity ratio. Even though stoichiometric values for thin films are achievable by varying the T s, 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.