CuInSe2 and CuGa1-xInxSe2, with x = 0.25, 0.5 and 0.75, films have been grown by 'flash' evaporation. Films 2 mu m thick over Mo coated glass have shown columnar grains, single chalcopyrite: phase and adequate optical and electrical proper ties as photovoltaic semiconductor. The film composition could be changed by modifying the deposition parameters, such as crucible and substrate temperatures and deposition rate. inherent problems in this technique. such as 'spitting', have been removed by changing die dimensions of the system and crucible type. A solar cell formed by depositing on top of the CuInSe2 a Cu-poor layer of composition close to CuIn2Se3.5 has shown about 6% efficiency.