Synthesis, crystal structure and optical properties of Ce doped CuInSe2 powders prepared by mechanically alloying

The rare earth element cerium doped CuInSe2 (CIS) powders were synthesized by mechanical milling processes and their structures and optical properties were determined using X-ray diffraction and optical measurement. X-ray diffraction analyses show that CuIn1−xCexSe2 (x = 0, 0.1, 0.2, 0.3) crystallize in tetragonal chalcopyrite structure with space group of I4¯2d. The single phase solid solution for CuIn1−xCexSe2 is in the range of x = 0-0.12. The crystal structure for a typical single phase CuIn1−xCexSe2 with x = 0.1 was determined with a Rietveld structural refinement method, it has a tetragonal chalcopyrite structure with the lattice parameters a = 5.781(5) Å and c = 11.584(2) Å. The energy band-gap of CuIn0.9Ce0.1Se2 powder is found to be 1.4 eV. The open-circuit voltage (VOC) of CuIn0.9Ce0.1Se2 based device was 73 mV. The results prove that the rare earth element cerium doped CIS is promising for application as the absorption layer in thin film solar cells.