CHARACTERIZATION OF ZNINXSEY THIN-FILMS AS A BUFFER LAYER FOR HIGH-EFFICIENCY CU(INGA)SE-2 THIN-FILM SOLAR-CELLS

The structural, optical and electrical properties of ZnInxSey (ZIS) th in films on Cu(InGa)Se-2 (CIGS) thin films and glass substrates were c haracterized. Polycrystalline ZIS thin films were grown by the coevapo ration method using three constituent elements. We confirmed the forma tion of ZnIn2Se4 from the X-ray diffraction patterns of the ZIS thin f ilms on glass substrates. From the transmittance and reflectance measu rements of these films, the bandgap of ZIS is estimated at around 2.0 cV in this study. In addition, the ZIS films on glass substrates show low dark conductivity and high photosensitivity, which are suitable fo r the buffer layer in CIGS thin-film solar cells. We also fabricated t he CIGS thin-film solar cells with a ZnO/ZIS/CIGS structure, and inves tigated the relationship between the cell performance and the beam int ensity ratio of zinc to indium.