Structural and physical properties of sprayed copper–zinc oxide films

Abstract

Mixed thin film oxides of different composition of copper and zinc were prepared by the spray pyrolysis technique. They were characterized by X-ray diffraction, transmission, and reflectance spectroscopy and electrical resistivity measurements. Structural analysis showed that a solid solution thin film of the composition (CuO) 1− x (ZnO) x with x≤0.1 is formed. At x≥0.15–0.20 hexagonal transparent crystallites of ZnO is formed between black CuO grains. Covalent shortening is a possible reason for the decrease of the volume of the unit cell of composition with x≤0.1. The changes of preferred orientation of the crystallites from (020) to (002) for films of composition ZnO≥0.15 affect greatly the film thickness. The variation of resistivity with increasing ZnO content in the film is attributed to the compensation effect between p-type CuO and n-type ZnO.