Photoluminescence Line at 2.29 eV in CuGaS2 Crystal

Abstract
A series of photoluminescence (PL) lines has been observed at 4.2 K in CuGaS2 single crystals grown by an iodine-transport method. They consist of a sharp sero-phonon line at 2.294 eV and phonon replicas. This PL series is discussed in connection with the phonon-assisted transitions observed for the zero-phonon lines at 2.397 and 2.404 eV.