RF Sputtering and Annealing Effects on Cu2SnS3 Thin Films: Structural, Optical, and Electrical Properties

This study presents a systematic investigation into the deposition of Cu₂SnS₃ (CTS) thin films via RF sputtering, aiming to optimize their structural, optical, and electrical properties for photovoltaic applications. CTS films were deposited under varying RF powers (150–300 W), and substrate temperatures were at room temperature. XRD analysis revealed a predominantly monoclinic crystal structure at an optimized annealing temperature of 500 °C and RF power of 300 W, with enhanced crystallinity and reduced secondary phases. SEM and EDS confirmed uniform, morphology, and near-stoichiometric composition under these conditions. UV–Vis-NIR spectroscopy indicated a direct optical bandgap of 1.24 eV, suitable for solar absorption. These optimized deposition parameters also minimized structural defects, improving light absorption and carrier transport. The improved electrical conductivity and interface quality suggest that CTS films produced under these conditions are strong candidates for efficient photovoltaic and optoelectronic devices.