Nickel-doped zinc oxide thin films made by spray pyrolysis: experimental characterization and theoretical analyses

A study of ZnO-based ceramic films prepared by the spray-pyrolysis technique is presented. Pure and Ni-doped thin film samples were deposited as a coating on a glass substrate and experimentally characterized using scanning electron and atomic force microscopies, X-ray diffraction, and UV-vis-NIR spectroscopy. The morphologic, crystallographic, and optical properties were analyzed. Structural and electronic properties were compared to predictions obtained from computational calculations based on the density functional theory plus U approach (DFT+U). All these simulations provided additional data that could be used as a reference for material modeling and a better understanding of the experimental results. It was found that spray pyrolysis can be used to produce thin film ceramic samples (~300 nm) with low amounts (<5%) of Ni impurities substitutionally located at the cationic sites of the ZnO wurtzite host structure. The results of this investigation showed that an experimental and theoretical study aided in a better characterization of the thin films, and helped to outline a more robust model of the samples.