THE EFFECT OF ANNEALING TEMPERATURE UNDER OXYGEN GAS ON ZnO THIN FILM MICROSTRUCTURE

Abstract

Zinc oxide (ZnO) thin films were deposited using the radio-frequency (RF) magnetron sputtering technique. The influence of post-annealing temperature under an oxygen atmosphere on the surface morphology, crystalline quality, and molecular vibrational properties of the films was systematically investigated. XRD analysis revealed that all ZnO films crystallized in the hexagonal wurtzite structure with a preferred (002) orientation, and that the crystalline quality improved with increasing annealing temperature. A significant reduction in the FWHM of the diffraction peaks was observed, accompanied by an increase in the effective crystallite size from 21.53 to 39.58 nm. AFM and SEM analyses showed that, upon reaching an optimal annealing temperature, the films became denser with increased surface roughness, indicating enhanced grain growth and surface diffusion. These results demonstrate that post-annealing treatment plays a crucial role in tailoring the microstructural and crystalline properties of ZnO thin films.