Synthesis and characterization of Cu3SbS4 thin films grown by co-sputtering metal precursors and subsequent sulfurization

Abstract

Cu₃SbS₄ (famatinite) thin films were synthesized using a two-step process: Cu and Sb metals were first deposited by RF magnetron sputtering, followed by subsequent sulfurization. The influence of metal precursor ratio, sulfurization temperature and time on surface morphology, composition, and structural and optical properties was systematically investigated. X-ray diffraction and Raman analysis revealed the formation of Cu₃SbS₄ phase thin films, where the crystallinity and phase purity improve with sulfurization temperature. Synthesis at a process temperature of 425 °C gave phase-pure Cu₃SbS₄ thin film with uniform surface morphology, whereas secondary phases were formed at reaction temperatures lower than 400 °C. A temperature higher than 425 °C led to films with voids between the crystallites. The bandgap of the optimized films was measured to be 0.89 eV and 0.83 eV using UV-VIS-NIR spectroscopy and spectroscopic ellipsometry measurements, respectively. This suggests the potential use of Cu₃SbS₄ as an absorber layer for thin film solar cells.