Using X-ray diffraction, UV-Visible spectroscopy, XPS and photoluminescence (PL) measurements, the structural, optical and electronic properties of ZnO and Cedoped ZnO thin films were investigated; the films were deposited on glass substrates by RF reactive-magnetron sputtering and post-annealed at 300 C in an oxygen atmosphere. Under similar deposition conditions, both films crystallized into hexagonal würzite lattice structures. The pure ZnO film exhibited a c-axis preferential orientation, whereas the Cedoped exhibited an a-axis preferential orientation. The films display uniform textured surfaces with columnar-like microstructures. The UV-Vis spectra showed high transparencies of 90 % on average for both films. Band gaps of E g ¼ 3:23 eV and E g ¼ 3:27 eV for pure and Ce-doped film, respectively, were measured. The doped film spectrum was shifted to the blue as a result of the Burstein-Moss effect. The XPS spectra show that the VB edge of the doped film shifts toward lower binding energy, at $ 1.3 eV below E F , while the VB edge of the pure film is located at $ 2.0 eV below E F . Additionally, Ce 3þ and Ce 4þ ions coexist in the ZnO matrix in fractions of $ 70 and $ 30 %, respectively. The PL spectra show that both types of ions induce extra electron states that allow multiple emission peaks in the blue-green region.

Zinc oxide films were deposited on glass substrates by RF reactive magnetron sputtering and post-annealed in vacuum at 100, 200, and 300 8C. Structural and optical properties of films were obtained using X-ray diffraction and UV-visible spectroscopy. Optical parameters were extracted from transmittance curves using the single-oscillator Drude-Lorentz model. The evolution of the optical and structural properties of films with the annealing process was investigated. The films crystallized into the hexagonal würzite lattice structure, with preferential growth along the c-axis [0002]. The results indicate that the crystalline quality of films improved with annealing, whereas transparency was reduced from 90 to 80 % at 300 8C. With post-annealing, the absorption edge shifted to the red, while the optical band gap decreased from E g ¼ 3:28 to E g ¼ 3:26 eV because of the Burstein-Moss effect. Calculated values of plasma frequency, w p ; fall within the IR range and decrease with temperature, from w p ¼ 5:56 Â 10 14 rad/s (2950 cm À1 ) to w p ¼ 1:1 Â 10 14 rad/s (587 cm À1 ).

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