Preparation and properties of CuIn_xGa_(1-x)Se_2 thin-film solar cell absorbers from selenization of Ga-rich electrodeposited precursors

摘要

This paper presents our studies on the preparation and properties of CuIn_xGa_(1-x)Se_2 (CIGS) thin-film solar cell absorbers grown from Ga-rich electrodeposited precursors followed by their selenization. X-ray fluorescence and scanning electron microscopy results show that the deposition potential of -0.7 V is suitable for obtaining a smooth CIGS precursor film with inclusion of more gallium (x = 0.4). X-ray diffraction studies reveal that a stoichiometric CuIn_(0.7)Ga_(0.3)Se_2 phase that can be formed by selenization of the Ga-rich precursor is ascribed to a high Se vapor pressure. An optical study shows that the band-gap energy of the stoichiometric CIGS sample is 1.17 eV. The best photovoltaic devices showed a conversion efficiency of 2.0 ±0.5%.