In this paper, we prepared Cu(In,Ga)Se2 thin films by using co-evaporation method, and analyzed the properties of the thin films. During the thin film preparation process, we confirmed InGaSe2 phase was formed at 400℃ in first stage, and also confirmed the thin films showed the vacancy decrease. In second and third stage,we confirmed the density increase of crystalline structure at over 480℃ and the formation of Cu(In0.7Ga0.3)Se2phase. As the result of SEM and XRD analysis of the films which were before and after heat-treated, we confirmed the disappearance of Cu2Se2 and the formation of Cu(In0.7Ga0.3)Se2 single phase after the heat-treatment,We, therefore, confirmed the heat-treatment did not affect the absorbency spectra of the thin films.
