Ce-doped ZnO nanocomposite thin films with Ce/Zn ratio fixed at optimum value (10 at.%) have been prepared via sol-gel method at different annealing temperatures varied from 180 to 500 degrees C. The synthesized samples were characterized employing atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) techniques. According to AFM analysis, the average grain size increased from about 70 nm to 150 nm by increasing the annealing temperature from 300 to 500 degrees C. Moreover, based on the XPS data analysis, it was found that three major metal ions namely Ce(3+), Ce(4+), and Zn(2+) coexist on the surface of the nanocomposite films. XPS data analysis also revealed that Ce(3+) ion is oxidized to Ce(4+) ion with increasing annealing temperature. Due to oxidation, the ratio of [Ce(3+)]/[Ce total] changed from 68.8 to 38.1% by increasing the annealing temperature from 180 to 500 degrees C. In addition, the Ce/Zn ratio increased from 0.21 to 0.42 when increasing the annealing temperature from 180 to 500 degrees C indicating migration of Ce ions toward the surface at higher temperatures. Finally, the XRD measurements determined that the ZnO thin films have a hexagonal wurtzite structure and CeO(2) crystallites are formed at 500 degrees C in the Ce-doped ZnO nanocomposite thin films. (C) 2011 Elsevier B.V. All rights reserved.