Polycrystalline CuInGaSe2 (CIGS) and CulnSe(2) (CIS) thin films were synthesized on glass substrates by a two-Stage selenization process. The surface morphology, phase structure and composition of the films were analyzed by scanning electron microscopy, X-ray diffraction and energy-dispersive X-ray analysis, respectively. Photoluminescence, optical transmission and reflection spectra were measured at temperatures from 4.2 to 300 K to characterize defects and the structural quality. The structural quality and evolution of defects in the CIS films grown at different temperatures and selenization time, and dependence of the band-Pp energy on the content of Ga in CIGS films at 78 K is discussed. (C) 2003 Elsevier B.V. All rights reserved.