Influence of Li atoms on the properties of ZnO thin films synthesized by sol-gel spin-coating method

Undoped and Li-doped ZnO(LZO) thin films were grown on quartz substrates by a sol-gel spin-coating method. The effects of Li contents on the structural and optical properties of the ZnO thin flims were investigated by X-ray diffraction (XRD), photoluminescence (PL), and ultraviolet-visible spectrophotometer. In the XRD investigation, undoped and LZO thin films had a wurtzite structure and high c-axis orientation. The intensity and the full width at half maximum (FWHM) of the (002) peak for LZO was the largest and smallest at 2.5 at%, which indicate that the LZO thin film is the most crystalline at 2.5 at%. In the PL investigation, the near band edge emissions of the LZO thin films were blue-shifted and the FWHM of the LZO thin films decreased with increasing Li doping concentrations.