Effect of Annealing Temperature on the Properties of Nickel Oxide Thin Films Prepared by Sol-gel Dip Coating

NiO thin films were deposited on quartz substrates by sol-gel dip-coating method using Ni(Ac) 2·4H 2O as the starting materials. XRD measurement results showed that for process temperature below 800℃, the grain size, the (200) diffraction peak intensity, and the orientation factor of the (200) diffraction peak increased as the temperature increased. For process temperature above 800℃, the opposite phenomena were observed. So the optimum process temperature for the deposition of NiO film by this method was 800℃. Optical band-gap measured by UV-Vis absorption revealed that the band-gap of NiO thin films showed an opposite trend compared to the grain size, which can be qualitatively explained by the quantum confinement effect caused by small grain size in the film.