Improved optical and structural properties of ZnO thin films by rapid thermal annealing

The influence of rapid thermal annealing (RTA) on the optical and structural properties of ZnO thin films grown on Si substrate has been investigated by X-ray diffraction (XRD), photoluminescence (PL), and Raman scattering (RS) measurements. The relaxation of the residual stress by increasing the annealing temperature during the RTA process was observed by the measured shift of (002) XRD diffraction peak towards 34.40∘ and the shift of RS E2E2 (high) mode closer to 437 cm−1. The process also resulted in a reduction of the measured full-width at half maximum (FWHM) of the PL emission line and that of the asymmetrical broadening of RS E2E2 (high) mode. The observed changes have demonstrated that RTA is a viable technique for improving the crystalline quality of ZnO/Si films.