Properties of ZnO thin film on Al2O3 substrate prepared by pulsed laser deposition under different substrate temperature

ZnO thin films were prepared on c-plane sapphire (Al2O3) substrates using pulsed laser deposition at different substrate temperatures (200, 300 and 400 °C). The effects of substrate temperature on the structural and stoichiometry properties of ZnO films have been investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results showed that crystalline and (0 0 2)-oriented ZnO films were obtained at all substrate temperatures. The stress in ZnO film changes from compressive to tensile according to the increasing of substrate temperatures. From Raman spectrum, the wutrize structure formed in the film when the substrate temperature exceeded 300 °C. The Raman spectroscopy, XRD and XPS results shows better crystal quality has been obtained under higher substrate temperature. Furthermore, stoichiometry of ZnO films was improved under higher substrate temperature.