Characteristic of ZnO films prepared by the sol-gel process

ZnO thin films with or without Al doping were grown on the glass substrates by sol-gel method and subsequently annealing treatments at high temperatures were performed to optimize films' morphologies and properties. The crystal structures of ZnO films were characterized by X-ray diffraction (XRD), and XRD spectra show a shift of (002) diffraction peak to the higher 20 values with changing the Al-doping concentration. Optical transmittance spectrums exhibit a sharp absorption edge at around 380nm undergoing a blue shift induced by aluminum doping. An apparent particle size decreasing was displayed by scanning electron microscopy (SEM) images with the Al-doping concentration increasing.