EFFECT OF ANNEALING ON STRUCTURAL AND OPTICAL PROPERTIES OF ZnO THIN FILMS BY SOL GEL TECHNIQUE

Zinc oxide thin films were prepared by sol gel spin coating technique using zinc acetate as precursor solution on glass substrate. The prepared films were annealed at three different temperatures to study the effect of annealing on the structural and optical properties of ZnO thin films. As-deposited and annealed films were characterized by X-ray diffraction (XRD), UV-Vis-NIR spectroscopy and photoluminescence spectroscopy. The XRD pattern shows that ZnO films are polycrystalline in nature and crystallite size increases with the increase in annealing temperature. Optical transmittance measurements were taken using UV-Vis-NIR spectrophotometer and the calculated values of the direct band gap energy, E-g was between 2.6 -3.13 eV. Photoluminescence spectra of films exhibit a huge band edge emission at similar to 383 nm. It was shown that the annealing temperature has significant effect on the properties of ZnO thin films.