The structural and optical properties of CuIn1 xGaxS2 CIGS , CdS CuIn1 xGaxS2, and ZnO CdS CuIn1 xGaxS2 polycrystalline films, with applications in photovoltaics, were studied by Raman and Photoreflectance PR spectroscopy for two different compositions, [Ga] [In] [Ga] 0.04 and 0.12, of the CuIn1 xGaxS2 absorber. The energy band gap of the absorber film was determined by fitting the PR spectra with a third derivative functional form. Moreover, the thickness of the film was calculated from the interference fringes observed in the PR spectra below band gap energy. Raman scattering was excited by the 514.5nm line of Ar laser and the 647.1nm line of Kr laser. The Raman spectra of the absorber films consist of phononmodes assigned to CuInS2, CuGaS2 and CuS. The results of the present study are discussed together with the results of SEM and XRD studies of the films and the results of electrical measurements performed on solar cells based on the CIGS absorber
