Formation Chemistry of Polycrystalline Cu(InGa)Se2 Thin-Film Absorbers Prepared by Selenization of Cu-Ga/In Stacked Precursor Layers with H2Se Gas
AbstractThe purpose of this study is to improve the reliability and reproducibility of our fabrication process for polycrystalline Cu(InGa)Se2 (CIGS) thin-film absorbers and to make a better absorber with higher efficiency. The current baseline process of selenization has been evaluated through the investigation of the formation chemistry of the device-quality CIGS thin-film absorbers with a graded band-gap structure. It has been verified that the current selenization process has been performed in a good balancing point with both Cu/III ratio and thickness of the precursor layer and the total amount of Se through H2Se gas incorporated from the surface during the selenization. A simplified model to explain the formation chemistry of the selenization in this study has been proposed.
CIGS thin film solar cells with graded-band gap fabricated by CIS/CGS bilayer and CGS/CIS/CGS trilayer systems