Growth of large-grain CuInSe2 thin films by flash-evaporation and sputtering

Thin films of (112) oriented CuInSe2, with an average grain size larger than 50 μm, have been grown by flash-evaporation and sputtering. Platelets of Corning glass 7059, 1 inch2 in size, covered by a layer of lead 2 μm thick, have been used as substrates. The lead layer is prepared by a new method which allows one to obtain (111) oriented films with a grain size ranging between 30 and 500 μm. This method is now being patented. Solar cells using CuInSe2/CdS thin films, prepared by flash-evaporating low resistivity CdS thin films on top of CuInSe2, have so far exhibited high photocurrents close to 40 mA cm-2 at 100 mW cm-2 solar illumination, and a maximum efficiency of about 4%.