CuInSe2 Formation by selenization of sequentially evaporated metallic layers

CuInSe2 (CIS) thin films were grown by selenization of sequentially evaporated metallic precursors. Different types of sequential processes of evaporation have been tested: Cu/In/Cu/In, In/Cu/In/Cu and In/Cu/In. The selenization procedure was carried out within a partially closed graphite container. The CIS films showed single-phase chalcopyrite structure with preferential orientation in the (1 1 2) direction after 500°C selenization. The CIS surface morphology depended on the sequence used. The In/Cu/In seemed to be the best. An energy band gap above 0.95 eV and an absorption coefficient near 105 cm−1 were obtained and similar optical properties were observed for all the prepared sequences.