Investigation of high-quality CuInSe2 films with various Cu/In ratios

High-quality CuInSe2 films with various Cu/In ratios were fabricated using hybrid sputtering and evaporation techniques. The Cu/In ratio was found to affect the structural and electrical properties of CuInSe2 films, resulting in a change in the conversion efficiency of CuInSe2 solar cells. CuInSe2 films with various Cu/In ratios were characterized by scanning electron microscopy (SEM), Hall effect measurements and X-ray diffraction (XRD). The lowest pit density was observed on the surface of CuInSe2 films with Cu/In ratio of 0.87. The CuInSe2 films are composed of two layers with large and small grains at the top and bottom, respectively. XRD revealed the surface of the CuInSe2 films to have a preferred orientation of (1 1 2) planes. The XRD intensity and full width at half maximum of the (1 1 2) plane of CuInSe2 varied according to the Cu/In ratio. The mobility estimated form the Hall effects revealed large changes in CuInSe2 films according to the Cu/In ratio. (C) 2011 Elsevier B.V. All rights reserved.