USE OF N-TYPE (CU2SE)(X)(IN2SE3)(1-X) ORDERED DEFECT CHALCOPYRITE FILMS FOR SOLAR-CELL ABSORBER LAYERS

The special attributes of CuIn3Se5 and related In-rich compounds from the (Cu2Se)(x)(In2Se3)(1-x) pseudobinary system are exploited for an a bsorber layer in a new thin-film photovoltaic cell. Single phase CuIn3 Se5 films are synthesized by co-evaporation. Bi-layered n-type films f rom the (Cu2Se)(x)(In2Se3)(1-x) pseudobinary system with Cu-rich surfa ces and 0.5 greater than or equal to x greater than or equal to 0.1, a re synthesized by sequential deposition. An electrochemical approach, first developed for CuInSe2, is employed to construct n-(Cu2Se)(x)(In2 Se3)(1-x)/p-CuISe3 heterojunctions. This approach leads to a remarkabl y uniform, clean np-heterointerface and a rough outer surface conduciv e to light trapping. EPMA, SIMS profiles and XRD analysis examine the (Cu2Se)(x)(In2Se3)(1-x) films and the CuISe3 overlayer. EBIC and I-V a nalyses investigate the formation of an electrically active n-CuIn3Se5 /p-CuISe3 junction.