Influence of post-thermal annealing on the properties of sprayed cadmium-zinc oxide thin films

We have prepared (ZnO)(x)(CdO)(1-x) thin films by spray pyrolysis. Mixed th in film oxides with different compositions of cadmium and zinc were deposit ed on glass substrates and exposed to different annealing treatments at a f ixed temperature. The effects due to post-thermal annealing on the structur al, optical and electrical properties of the variable composition thin film s have been studied depending upon the x value. The crystalline structure w as studied by X-ray diffraction (XRD). We found the presence of CdO XRD pat terns for low Zn concentrations, and a mixing of CdO (cubic) and ZnO (hexag onal) phases for low Cd concentrations. In all cases. the crystallite sizes increased with the annealing. In addition, the band-gap and the resistivit y vary between those found for pure CdO and ZnO. The changes of the latter parameters with the post-thermal annealing are studied also as a function o f the x value. (C) 2000 Elsevier Science B.V. All rights reserved.