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Effect of annealing temperature on growth of Ce-ZnO nanocomposite thin films: X-ray photoelectron spectroscopy study

Yousefi, M ; Sharif University of Technology | 2011

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  1. Type of Document: Article
  2. DOI: 10.1016/j.tsf.2011.06.081
  3. Publisher: 2011
  4. Abstract:
  5. 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 °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 °C. Moreover, based on the XPS data analysis, it was found that three major metal ions namely Ce 3+, Ce4+, and Zn2+ coexist on the surface of the nanocomposite films. XPS data analysis also revealed that Ce3+ ion is oxidized to Ce4+ ion with increasing annealing temperature. Due to oxidation, the ratio of [Ce3±]/[Ce total] changed from 68.8 to 38.1% by increasing the annealing temperature from 180 to 500 °C. In addition, the Ce/Zn ratio increased from 0.21 to 0.42 when increasing the annealing temperature from 180 to 500 °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 CeO2 crystallites are formed at 500 °C in the Ce-doped ZnO nanocomposite thin films
  6. Keywords:
  7. Ce-doped ZnO ; AFM ; Annealing temperatures ; Average grain size ; Hexagonal wurtzite structure ; Higher temperatures ; Major metal ; Nanocomposite thin films ; Optimum value ; X-ray photoelectron spectroscopy studies ; XPS analysis ; XPS data ; XRD measurements ; ZnO ; ZnO thin film ; Annealing ; Atomic force microscopy ; Atomic spectroscopy ; Data reduction ; Gels ; Metal ions ; Nanocomposite films ; Nanocomposites ; Photoelectricity ; Photoelectron spectroscopy ; Photons ; Sol-gel process ; Sol-gels ; Sols ; Thin films ; X ray analysis ; X ray diffraction ; X ray photoelectron spectroscopy ; Zinc oxide ; Zinc sulfide ; Cerium
  8. Source: Thin Solid Films ; Volume 520, Issue 2 , November , 2011 , Pages 721-725 ; 00406090 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0040609011013587