Influence of substrate temperature on properties of nc ZnO-SiOx thin films grown by rf co-sputter deposition

We investigated the effect of substrate heating on nanocomposite (nc) ZnO-SiOx thin films grown by rf co-sputter deposition. Results show that structural and optical properties depend strongly on the substrate temperature. With increase of substrate temperature, ZnO nanocrystals grow with better UV absorption, lower defects, better crystalline quality and migrate from surface to subsurface regions of the film, but the content and crystalline quality of Zn2SiO4 phase increases. For the substrate temperature of 750 °C, ZnO quantum dots with band gap of 3.48 eV are embedded in a higher band gap (5.08 eV) rhombohedral Zn2SiO4 containing silica. The results show that substrate temperature can be used to control the content and crystalline quality of ZnO and ZnxSiOy phases in the films and hence tune them for different applications.