Use of diethylselenide for the preparation of CuInGaSe2 films by selenization of metal precursors premixed with Se

The use of a less-hazardous organometallic Se source, diethylselenide [(C2H5)2Se: DESe], enabled to grow single-phase CuInGaSe2 solid solutions for high-efficiency solar cell application by the selenization of metal precursors without additional thermal annealing. Distinct from the case using Se vapor or H2Se gas, uniform CuInGaSe2 films were obtained from Cu-In-Ga metal precursors premixed with Se. In contrast, the films formed from Se-free precursors separated into two phases with different compositions. Photoluminescence spectra of approximately 2.0-μm-thick films at 77 K were dominated by the defect-related donor-acceptor pair and free electron-to-acceptor recombination emissions particular to the CuInGaSe2 films that are used for high conversion efficiency solar cells. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)