Characterization of Ga-Se and In-Se Based Semiconductors as Cd-Free Buffer Layer in Cu(InGa)Se_2 Thin Film Solar Cells

摘要

Structural control of Ga-Se and In-Se based semiconductors was investigated for the application to the buffer layer in Cu(INGa)Se_2 thin film solar cells. GaSE epitaxial films and Ga_2Se_3 epitaxial films were obtained on (001)GaAs for low VI/III ratios and high VI/III ratios, respectively. Besides, InSe and In_2Se_3 epitaxial films were successfully grown on (001)GaAs. Furthermore, Ga_2Se_3 and In_2Se_3 films were found to have a wide-bandgap, very low dark conductivity and high photoconductivity, showing that Ga_2Se_3 and In_2Se_3 are suitable for buffer layers of Cu(InGa)Se_2 thin film solar cells.