Preparation and Characterization of ZnO Nanocrystalline Layers

Abstract

This work consists on the study of the optical properties of zinc oxide layers. These Layers are elaborated under various conditions by cathode sputtering on glass substrates and by thermal oxidations of Zn layers deposited on different types of substrates by vacuum evaporation. The oxidation treatments of Zn are made in oxygen atmosphere at temperatures between 400˚C and 450˚C for different times. The analyses by diffraction of X-rays, Optical Microscopy and Scanning electron microscopy enabled us to understand that the zinc oxide films deposited by cathode sputtering on a glass substrate and having a thickness of at least 240 nm and those prepared by thermal oxidation at 450˚C during 2 hours of layers of Zn on an alumina substrate are homogeneous and consist of grains of size 30 nm. The optical transmission measurements show that the gap is around 3.02 eV for layers obtained by oxidation and 3.3 eV for those deposited by sputtering. These samples have a good optical transparency in the visible.