A Novel combined thermal evaporation and solvothermal approach to produce highly crystalline and compact CIG(S1-xSex)2 thin films

This research introduces a novel approach that combines thermal evaporation with cost-effective solvothermal methods to produce highly crystalline CIGSe thin films. By avoiding the use of expensive and pure target materials and reducing the selenization step, this method offers an alternative to co-evaporation or sputtering techniques. The study investigates the growth mechanism and sulfurization of the films, resulting in improved crystallinity, absence of secondary impurities, and compact morphology. The sulfurization process is achieved at a low temperature using a safe and convenient method, enhancing the film properties for high-performance solar cells. In this study, the CIGSe powder was synthesized using the solvothermal technique and thermally evaporated onto Mo-coated glass substrates. The resulting films exhibited improved crystallinity and a single-phase structure upon RTP annealing at 600 °C. Characterization techniques confirmed the presence of chalcopyrite crystal structure and the coexistence of CISe, CIGSe, and CGSe phases within the films. The sulfurization process, conducted at a relatively low temperature of 500 °C using an RTP furnace, led to compact morphology, increased grain size, and the absence of secondary phases. These findings demonstrate the feasibility of the proposed approach for fabricating efficient and environmentally friendly CIGSe-based solar cells.