CuIn1−xAlxS2 thin films prepared by sulfurization of metallic precursors

Abstract CuIn 1− x Al x S 2 thin films ( x  = 0, 0.09, 0.27, 0.46, 0.64, 0.82 and 1) with thicknesses of approximately 1 μm were formed by the sulfurization of DC sputtered Cu–In–Al precursors. All samples were sulfurized in a graphite container for 90 min at 650 °C in a 150 kPa Ar + S atmosphere. Final films were studied via X-ray diffraction (XRD), scanning electron microscopy (SEM) and micro-Raman spectroscopy. It was found that all samples were polycrystalline in nature and their lattice parameters varied slightly nonlinearly from { a  = 5.49 A, c  = 11.02 A} for CuInS 2 to { a  = 5.30 A, c  = 10.36 A} for CuAlS 2 . No unwanted phases such as Cu 2− x S or others were observed. Raman were recorded at a room temperature and the most intensive and dominant A 1 phonon frequency varied nonlinearly from 294 cm −1 (CuInS 2 ) to 314 cm −1 (CuAlS 2 ).