Temperature dependent electrical and optical properties with higher photosensitivity of Cu2Se absorber thin films for photo voltaic application

Cu2Se thin films were deposited on glass substrates by simple, low cost chemical bath deposition method and the films were annealed at 100 degrees C, 200 degrees C and 300 degrees C. The structural analysis (XRD) shows cubic structured Cu2Se and it was well crystallized at 200 degrees C annealing temperature. Surface morphology of the films indicates irregular shaped particles without any cracks. The particle size is found to be increased with annealing temperature. The elemental composition of the Cu2Se thin films was confirmed by EDAX analysis. The deposited Cu2Se thin films exhibited higher optical absorption in the visible region and the band gap values are found to decrease in the range of 1.85-1.73 eV due to increasing crystallite size of the films. The deposited films show good photovoltaic behavior and it is increased with annealing temperature. The photosensitivity study confirms that the compound Cu2Se can be considered as a potential candidate for solar cell application.