Characterization of Cu₃SbS₃ thin films grown by thermally diffusing Cu₂S and Sb₂S₃ layers

Copper antimony sulfide (Cu₃SbS₃) with a p-type conductivity and optical band gaps in the range of 1.38 to 1.84 eV is considered to be a promising solar harvesting material with non-toxic and economical elements. In this study, we reported the fabrication of Cu₃SbS₃ thin films using successive thermal evaporation of Cu₂S and Sb₂S₃ layers followed by annealing in an argon atmosphere at a temperature range of 300–375 °C. The structural and optical properties of the as-deposited and annealed films were investigated. The annealed films notably show the crystalline phase of Cu₃SbS₃, identified from the X-ray diffraction analysis and endorsed by the Raman analysis as well, whereas the chemical state of the constituent elements was characterized using X-ray photoelectron spectroscopy. The measured highest resistivity of the annealed film was found to be ~ 0.2 Ω-cm. Hence, our obtained results for the fabricated Cu₃SbS₃ thin films bring to light that these films would be good as absorber layer in solar cells due to their low resistivity, higher optical absorption coefficient (~ 10⁵ cm^− 1), low transmittance (< 5%) and an optical direct band gap of 1.6 eV in the visible range of the solar spectrum.