CuIn_1-xAl_xS₂ thin films prepared by sulfurization of metallic precursors

CuIn_1-xAl_xS₂ 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 , c = 11.02 } for CuInS₂ to {a = 5.30 , c = 10.36 } for CuAlS₂. No unwanted phases such as Cu _2-xS or others were observed. Raman were recorded at a room temperature and the most intensive and dominant A₁ phonon frequency varied nonlinearly from 294 cm^-1 (CuInS₂) to 314 cm ^-1 (CuAlS₂).