Effect of RF Power on the Structural and Optical Properties of Zinc Sulfide Films

Zinc sulfide (ZnS) films were prepared via a radio frequency (RF) magnetron sputtering technique using different RF powers (100, 120, 150, and 180 W), and the effects of the RF power on the structural and optical properties of the films were studied using x-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, ultraviolet-visible spectroscopy, spectroscopic ellipsometry, and laser photoluminescence spectroscopy. It was found that the RF power has an important impact on the predominant phase formation and crystallinity of the ZnS films. The film thickness, refractive index, and film to bulk relative density increase systematically with an increase in the RF power. Among the various RF power values investigated, 150 W was optimal for the growth of highly crystalline ZnS films with a predominance of the cubic phase and enhanced photoluminescence emissions.