Structural analysis of Cu(In,Ga)Se2 films fabricated by using sputtering and post-selenization

We made Cu(In,Ga)Se2 (CIGS) films by using sputtering and post-selenization. First, we deposited stacked metallic films by using the sputtering method and then carried out post-selenization for the precursor stacked metals with different amounts of Se powder, 0.160 g, 0.321 g, 0.642 g, and 0.964 g. We found that with a small amount of Se, separated CuInSe2 and CuGaSe2 layers were formed, which was confirmed by X-ray diffraction (XRD), Raman spectroscopy, and energy-dispersive X-ray analysis. For larger Se amounts, the CIGS phase was observed in the results of XRD and Raman spectroscopy. These results indicate that the amount or the partial pressure of Se plays an important role in the reaction kinetics for stacked precursor metals to form the CIGS phase.