Influence of annealing temperature on the structural and optical properties of sol-gel prepared ZnO thin films

Zinc oxide thin films have been prepared via a sol-gel process. The influence of annealing temperature on the structural and optical properties of the ZnO thin films has been investigated. The prepared ZnO, thin films had a polycrystalline hexagonal wurtzite structure with no preferred orientation. The annealing temperature had a great effect on the optical properties of the ZnO thin films: the optical band gap became narrow due to the increase in crystallite size and the reduction in amorphous phase amount with increasing annealing temperature. Absorption or desorption of oxygen in the annealing process caused the observed yellow or green emission. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.