Crystal growth and photoluminescence of CuInXGa1−XSe2 alloys

CuIn X Ga 1-X Se 2 (CIGS) alloys which can be used in photovoltaic applications have been prepared by a normal freezing (NF) method. The crystal structure, composition and conductivity types in the obtained CIGS crystals have been examined by X-ray diffraction (XRD), electron probe microanalysis (EPMA) and thermoprobe analysis, respectively. All samples are of the chalcopyrite structures, nearly stoichiometric and p-type. The grown CuInSe 2 (CIS) sample is of high quality since the free-exciton emission line is clearly observed in photoluminescence (PL). The CIGS samples turn out to have many acceptor-type defects because the free-to-acceptor emission bands show considerable intensities in the PL spectra.