GROWTH OF CUIN3SE5 LAYER ON CUINSE2 FILMS AND ITS EFFECT ON THE PHOTOVOLTAIC PROPERTIES OF IN2SE3 CUINSE2 SOLAR-CELLS/

The growth of CuIn3Se5 layer on bulk CuInSe2 films has been studied fo r the fabrication of CuInSe2 solar cells, using the three-stage proces s which involved the sequential evaporation of In-Se, Cu-Se, and In-Se elemental sources. After growing CuInSe2 films, the film surface was converted to a defect chalcopyrite (CuIn3Se5) compound. The X-ray diff raction and AES depth analysis indicated the formation of the CuIn3Se5 phase on the CuInSe2 surface. By the formation of the CuIn3Se5 phase, the absorption edge was shifted from 1200 to 1000 nm wavelength and t he binding energies of Cu, In, and Se were shifted to higher energies. The current-voltage curves of In2Se3/CuInSe2 cells fabricated with a thick CuIn3Se5 layer on a CuInSe2 film displayed a kink effect which w as possibly caused by the increase of series resistance and light abso rption in the CuIn3Se5 layer instead of the junction region. The cells with a thin CuIn3Se5 layer at the In2Se3/CuInSe2 interface yielded so lar efficiency of 8.46% with an active area of 0.2 cm(2). (C) 1998 Els evier Science S.A. All rights reserved.