Photoluminescence study of CuInSe2 thin films prepared by the selenization technique

CuInSe₂ thin films were prepared by the selenization technique with solid- or vapor-phase selenium, and photoluminescence measurements were carried out to identify the energy levels associated with various defect structures. The possible origins of these defect states are discussed based on the reported energy band diagram of single-crystal and thin film CuInSe₂. In the spectra of the films selenized with solid-phase selenium, the transition from the conduction band to the indium-vacancy level and the transition from the selenium-vacancy level to the copper-vacancy level are dominant for copper-rich and indium-rich films, respectively