Preparation of CuInGeSe4 thin films by selenization method using the Cu–In–Ge evaporated layer precursors Original Research Article

CuInGeSe4 quaternary compounds are known to have a chalcopyrite-like structure and have band gaps of about 1.3 eV, suitable for optimum conversion efficiency for solar cells. We have prepared the CuInGeSe4 thin films by the selenization method using the Cu–In–Ge evaporated layer precursors. The analyses of X-ray diffraction show that the single phase of CuInGeSe4 is obtained by the selenization of precursors at 450–500 °C. The SEM observation of film surface shows that the grain sizes are in the order of 1–2 μm. The band gaps of selenized films close to 1.6 eV are wider than that of bulk crystals (about 1.3 eV). These films have p-type conduction and higher electrical resistivities than more 105 Ω cm at room temperature.