Effect of annealing on structural and optical properties of zinc oxide thin film deposited by successive ionic layer adsorption and reaction technique

Zinc oxide thin films are grown by successive ionic layer adsorption and reaction technique at room temperature. The as-grown films were annealed at different temperatures, viz. 350, 400, 450, and 500 °C in air atmosphere for 2 h. Effect of annealing on the physical properties of ZnO thin films has been studied. XRD analysis reveals the polycrystalline nature for ZnO thin films with hexagonal phase. The films were highly oriented along (1 0 0) and (1 0 1) planes, an enhancement in these peaks is the significance of the post-deposition annealing treatment on ZnO thin films. The optical studies of the samples show that the energy band gap was decreased in accordance with the annealing temperature. The results of optical studies were strengthened by photoluminescence (PL) studies.