ZnO thin films have been prepared by sol–gel method in this paper. Zinc acetate, ethanol and mono-ethanolamine (MEA) were used as a metal precursor, solvent and stabilizer, respectively. The structural and optical properties of ZnO thin films were investigated and found to be strongly dependent on the annealing temperature. X-ray diffraction patterns revealed that as the annealing temperature increased, the crystalline quality of the samples became better. The atomic force microscope images of the samples show larger and compact grains at higher heat-treating temperature. The ultraviolet–visible transmittance spectra indicated that as the temperature increased, the transmittance improved and the energy gap became larger (from 3.11[Formula: see text]eV at 400[Formula: see text]C to 3.22[Formula: see text]eV at 500[Formula: see text]C). The photoluminescence spectra presented a variety of emission peaks, two strong peaks at 390[Formula: see text]nm and 469[Formula: see text]nm, respectively, from the intrinsic emission and point defects, and the intensity of these peaks decreased with the increase of temperature.
