Optical properties and synthesis of CuInSe2 thin films by selenization of Cu/In layers

In this paper, we report the effect of annealing temperature on the properties of copper indium diselenide (CuInSe2) thin films. The CuInSe2 thin films were fabricated at 500 degrees C for 2 h by annealing Cu-In layers (as precursors) selenized in a glass tube with pure selenium powder. The structural and morphological properties of the CuInSe2 thin films were characterized respectively by means of x-ray diffraction (XRD) and field-emission scanning electron microscope (FE-SEM). The type of CuInSe2 thin film has been identified as direct allowed and the band gap value was determined. The study of UV/Visible/NIR absorption shows that the band gap value of CuInSe2 thin film is about 1.07 eV, which is within an optimal range for harvesting solar radiation energy. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)