Cu3BiS3 film synthesis through rapid thermal processing sulfurization of electron beam evaporated precursors

In response to the increasing demand for sustainable energy solutions, Cu 3 BiS 3 (CBS) films emerge as a promising alternative for cost-effective and eco-friendly photovoltaic absorbers. This work explores the synthesis and characterization of CBS films via sulfurization of metallic Cu and Bi precursors deposited using electron beam evaporation. We investigated the effects of both duration and temperature during the Rapid Thermal Processing (RTP) sulfurization. Using SEM/EDS, XRD, Raman spectroscopy, and UV-VIS-NIR transmittance measurements, we demonstrate the successful formation of the CBS Wittichenite phase with band gap energies $$\:{E}_{g}\approx\:1.4\:eV$$ , and absorption coefficients $$\:\alpha\:\ge\:{10}^{4}\:{cm}^{-1}$$ , highlighting the CBS potential as a viable alternative as a photovoltaic absorber. We achieved films with the dominant CBS phase, with large highly crystalline grains but still containing some undesired copper sulphide secondary phases. These films were obtained at low RTP temperatures (350 °C) and short durations (5 min), ensuring both time and energy efficient consumption, in contrast to commonly reported lengthy, high-temperature processes. Graphical abstract