Photoluminescence Properties of Zinc Tungstate Films Prepared by Sol-Gel Method

Abstract

Zinc tungstate (ZnWO4) polycrystalline films have been prepared on glass slide substrates by sol-gel method using ammonium paratungstate and zinc acetate as starting materials. The films deposited were subsequently sintered at 573 K to 723 K, and atomic force microscope (AFM) and X-ray diffraction (XRD) were used to analyze the surface topography and crystal structure respectively. XRD results show that the ZnWO4 phase can form only when the annealing temperature is up to 623 K. The photoluminescence properties of the films were measured, and the results show that the photoluminescence excitation wavelength of the films shifts towards the violet with decrease of film annealing temperature. Additionally, low annealing temperature and too thin film will lead to the appearance of ZnO luminescence. It is suggested that the composite structure of emission band was caused by the self-trapped excitation and two transition processes of (WO6)6−.