Effect of Annealing on Co-Doped ZnO Thin Films Prepared by Nanocluster-Beam Deposition

Co-doped ZnO nanocluster-assembled thin films fabricated by nanocluster-beam deposition have been annealed at 400 and 700 °C. The influence of annealing temperature on the structural, optical, and magnetic properties has been characterized by various diagnostic techniques. It can be found that the crystalline nature and structure were significantly enhanced after the annealing of the as-grown films. When increasing the temperature, the shoulder of the absorbance spectra turned steeper and the intensity of curves become weaker in the range of 210 to 350 nm. A relatively strong UV emission band was detected at around 379 nm. The saturation magnetization of the film annealed at 700 °C was higher than the as-grown one, but it was lower than the films annealed at 400 °C, which may be caused by the decrease in oxygen vacancy with rising the annealing temperature.