Use of diethylselenide as a less-hazardous source for preparation of CuInSe₂ photo-absorbers by selenization of metal precursors

Diethylselenide [(C₂H₅)₂Se: DESe] was shown to be a promising less-hazardous alternative source for the preparation of CuInSe₂ films for solar cell applications by the selenization of Cu-In and Cu-In-O precursors. Approximately 1.5 μm thick, single-phase, polycrystalline CuInSe₂ films having grain size of approximately 1-2 μm were formed on Mo-coated soda-lime glass substrates at temperatures between 450° and 550°C. Slightly In-rich films exhibited a distinct contribution by excitonic absorption in the absorption spectra at 90 K. Photoluminescence spectra at low temperatures were dominated by characteristic bands at 0.97 and 0.90 eV, showing that the films are a suitable material for the photo-absorbing layer of CuInSe₂-based solar cells.