In this study, we have investigated the correlation between nickel and ultraviolet emission in SiOx (x < 2) films. Due to the presence of nickel, the maximum intensity of UV emission was obtained after annealing at 800 degrees C, which was explained by the formation of oxygen excess defects in the oxireduction reaction between Ni and SiOx. The intensity of ultraviolet emission increases by annealing in oxygen because the process of oxidation is benefit to the formation of oxygen excess defects. The mean size of SiOx clusters increases with the increase of annealing temperature, which is characterized by scanning electron microscopy and energy dispersive spectroscopy analysis. An odreduction reaction model was proposed to explain the correlation between nickel and ultraviolet emission in this system. (c) 2005 Elsevier B.V. All rights reserved.