Morphological and photoluminescence analysis of zinc oxide thin films deposited by RF sputtering at different substrate temperatures

Zinc oxide (ZnO) thin films were prepared using reactive RF magnetron sputtering of a pure metallic zinc target onto n-type (100) silicon substrates. The evolution of the surface morphology and the optical properties of the films were studied as a function of the substrate temperature, which was varied from ambient to 300°C. X-ray diffraction pattern of ZnO thin film shows the appearance of c-axis oriented (002) peak for all samples shows varying degrees of crystallinity of films. Photoluminescence studies were also carried out (350-700 nm) to study the crystallinity and optically active defects in the films. PL spectra of the film shows UV emission peak depicts good crystallinity of ZnO film where as the intensity of deep level emission band decreases with increase in substrate temperature due to the formation of stoichiometric ZnO film which causes decrease in defect.