The purpose of this study was to investigate the effect of different copper ratios on the quality of CuxIn0.7Ga0.3Se2 (CIGS) film, where x=0.8, 0.9, 1, 1.1, 1.2, and to find the copper ratio that is most suitable for growing CIGS crystals, thereby improving the quality of the overall CIGS film.
We use a two-stage process to pre pare CIGS films. In the first stage of the process, we provide a simple, non-toxic and low-cost method for the preparation of CIGS solution: through the direct use of metal powder as reaction materials, and the use of polyetheramine (D400) as a solvent in a nonvacuum process. A nano-solution of CIGS was prepared using a solvothermal refluxing method, and then CIGS film was prepared on a glass substrate by a doctor's blade method.
In the second stage of the process, we placed the CIGS film in a two zone tube furnace to perform pressurized closed selenization, while having nitrogen gas filled up the entire tube. The selenium powder is heated with the condition of 550 ° C for 30 minutes to provide selenium compensation. The CIGS film after the pressurized closed selenization process will be analyzed by XRD, SEM, EDS, Raman and UV-Vis to discuss the best selenization conditions. According to the analysis of material properties, CIGS films with good crystallinity were obtained at a copper ratio of 1.1 (Cu-rich).