Formation of high performance nanostructured ZnO thin films as a function of annealing temperature: structural and optical properties

Abstract Zn thin films are deposited on quartz substrate by DC magnetron sputtering method under the same condition. Then, ZnO nanoparticles are produced by heating Zn thin films in the open air at temperatures of 300, 500, 700, 900, and 1100°C for 2 hours. XRD analysis of these films shows that except for the 1100-ZnO sample, which has a cubic structure, the rest of the films confirm the hexagonal crystal structure of the Wurtzite. An examination of the ultraviolet spectrum and the calculation of optical parameters also indicate that annealing temperature is an influential factor on optical properties of high-quality ZnO thin films. Also, changes in optical energy bandgap of the samples correspond to the Burstein-Moss theory. Examination of the spectrum of photosynthesis through severe exciton emission demonstrates a minor defect in ZnO nanoparticles prepared this way. In general, findings indicate that physical properties of ZnO thin films are affected by annealing temperature, and among the samples, 700-ZnO sample displays the optimum optical and structural properties.