Structure and UV photoluminescence of nanocrystalline ZnO films prepared by thermal oxidation of ZnS films

Nanocrystalline ZnO films were fabricated using thermal oxidation of ZnS films deposited by successive ionic layer adsorption and reaction (SILAR) method. The crystalline structure and morphology of obtained films were characterized by X-ray diffraction (XRD) and scanning electronic microscope (SEM). Optical properties including the optical absorption coefficient and photoluminescence were investigated. Results show that obtained ZnO film exhibits excellent crystalline structure with the preferential orientation of 〈1 0 0〉, dense morphology with particle size of 20–50 nm, high transmittance over 80% in vis–near-infrared band, and sharp absorption edge near 380 nm. At the excitation of 340 nm photon, the film shows a strong and sharp ultraviolet emission at 390 nm and several weak emissions in blue band, illustrating its high optical quality. The oxygen content in the annealing atmosphere has significant effects on the structure and optical properties of ZnO film.