PREPARATION OF CUINSE2 FILMS ON LARGE GRAIN CDS FILMS FOR SUPERSTRATE-TYPE SOLAR-CELLS

Superstrate-type CuInSe, solar cells were fabricated by preparation of CuInSe2 films on CdS films with large grains. The CdS films with large grains were obtained by annealing of evaporated films with CdS:CdCl2, powders. The horizontal grain size of the annealed CdS films was about 3 times as large as the film thickness. The orientation of the CuInSe2 films on the CdS films was evaluated by X-ray diffraction, The CuInSe2 films on the annealed CdS films had a preferred orientation with (102) or (110) plane parallel to the substrate, while that on the evaporated CdS films highly oriented along [112] direction. The grains of the CuInSe2 films grew along several directions on the different CdS gains. As a result of the measurement of I-V characteristics under illumination, the cells using the large grain CdS films had higher J(SC) than that using the evaporated CdS films. The best cell performance obtained was Tr(OC) = 0.357 V, J(SC) = 32.2 mA/ cm(2) and FF = 0.582 in 0.075 cm(2) area. The conversion efficiency of the cell was 6.71%.