In this study, Cu(In,Ga)Se-2 thin films were prepared using a Cu-In-Ga metallic precursor and diethylselenide (DESe) vapor. The Cu/(In+Ga) ratio of the precursor was adjusted by modulating the power impressed on the CuGa target. The Cu/(In+Ga) ratio was varied from 0.45 to 1.02, and the prepared precursors were selenized in a 500 degrees C quartz furnace using DESe. The results showed that the preferred crystal phase and the uniformity of the thin film differed according to the composition of the precursor. After selenization, changes in grain size stemming from Cu composition were observed, and the occurrence of a binary phase was verified through KCN etching. Shifts in the Cu-11(InGa)(9) peak and the separation of CIS and CGS peaks relative to increased Ga content were also observed.