Study of Structural and Optical Properties of ZnO Films Prepared by Thermal Oxidation of Sputtered Zn Films

In this work, ZnO films were prepared by thermal oxidation of sputtered Zn films . Influences of oxidation temperature and thickness of Zn films on nanostructure, including crystal structure and surface morphology of ZnO films were investigated . The crystal structure, surface morphology, and optical transmittance of ZnO films were studied via X - ray diffraction ( XRD ) , field emission scanning electron microscopy ( FE - SEM ) , and UV - Vis spectrophotometer, respectively . It is clearly seen that the changing of nanostructure and crystal structure of ZnO films depended on the oxidation temperature . Surface morphology of ZnO films changed from nanoflakes to nanosphere with increasing the oxidation temperature from 200°C to 400°C . Furthermore, nanopore is enhanced when increasing the thickness of Zn films at oxidation temperature of 800°C . Changing of nanostructured ZnO films from the oxidation temperature is described with growth mechanism from vapor - liquid - solid ( VLS ) process . Moreover, optical transmittance of ZnO films exhibited transparence at oxidation temperature of 300°C and above . Finally, nanostructured ZnO films are tested for surface of hydrophobic property which showed the highest water contact angle at 133 . 1° for oxidation temperature of 800°C and 500 nm thick of Zn film . Keywords : ZnO films ; nanostructure ; thermal oxidation ; oxidation temperature