Structural and Optical Properties of CuInS2Thin Films Prepared by Magnetron Sputtering and Sulfurization Heat Treatment

Abstract

CuInS2thin films were prepared by sulfurization of Cu-In precursor films through magnetron sputtering and the resulting films characterized using X-ray diffraction, Raman spectrometry, and UV-Vis spectrophotometry. The results demonstrate that a sputtering power of 80–120 W is more suitable for sputtered Cu-In precursor films and can be used to obtain CuInS2films with good crystallinity through vulcanization heat treatment. The sputtering gas pressure and sulfurization temperature were shown to impact on the film quality due to improper processes during the CuInS2phase. Some of the CuIn11S17and CuS2impurities were observed in the composition of the prepared CuInS2thin films. Optimization of process parameters obtained from the experimental data was determined as a sputtering power of 80~120 W, a sputtering gas pressure of 0.6–0.8 Pa, a heat treatment temperature of 450~470°C, and a holding time of 2~3 hours. The optical band gap obtained for CuInS2thin films is between 1.48 and 1.5 eV.