Effect of Substrate Temperature on Crystalline Property of Cu(In,Ga)Se₂ Thin Film Grown at Low Temperature

Cu(In,Ga)Se2 (CIGSe) thin films were deposited on polyimide substrate using the low-temperature three-stage co-evaporation process. The crystalline quality and crystal structure of the CIGSe thin films were investigated by scanning electron microscopy and X-ray diffraction. The effects of substrate temperatures of the second/third stages on grain size, texture orientation and ctystalline property were analyzed. The resutls show that, with the increase of the substrate temperatures of the second/third stages simultaneously, the grain size increased and the Ga phase separation disappeared gradually. Keeping the substrate temperature of the second stage unchanged, with the increase of the substrate temperature of the third stage, the grain size of CIGSe thin film continued to increase and the crystalline quality of the film was improved obviously. The change of the substrate temperatures of the second/third stages had unobvious effect on the texture orientation of the CIGSe thin film.