Optoelectronic, structural and morphological analysis of Cu₃BiS₃ sulfosalt thin films

Sulfosalts are well known naturally occurring mineral species since the surprise mineralogy and are well reported for a variety of applications including photovoltaics. In the current study Cu₃BiS₃ (wittichinite mineral), a member of the sulfosalt family was crystallized by a simplified route through chemical bath deposition. To elaborate the experimental design and deposition mechanism and for the sake of comparison, Bi₂S₃ thin films were also deposited. X-Ray Diffraction, Scanning Electron Microscopy, Atomic Force Microscopy, UV–Vis Spectroscopy, and the Hall effect were used to explore the structural, morphological, and optoelectronic behaviour of synthesized materials in the form of thin films. The thickness of the films was measured by ellipsometry. XRD analysis confirmed the Bi₂S₃ for the first bath, while for the rest of the films Cu₃BiS₃ phase emerged. Optical bandgap values of 1.0 eV and 1.25 eV were achieved for Bi₂S₃ and Cu₃BiS₃ thin films respectively. Results revealed that Cu₃BiS₃ thin films deposited for 6 h at room temperature demonstrated Hall mobility of 34.9 cm² v⁻¹ s⁻¹, the charge carrier concentration of 6.07 × 10¹⁶ cm⁻³ and 7.22 O-cm resistivity with the thickness of 126 nm, hence validating the potential of synthesized materials for photovoltaic applications.