Optical Properties of CuInSe2 and Related Compounds

Reflectivity and photoluminescence (PL) spectra of stoichiometric and of two nonmolecular defect structures tied to the liquidus composition and are presented. At room temperature the fundamental gap and high energy features in the reflectivity spectra show only a very weak dependence on the stoichiometry of the compounds, while the PL spectra exhibit distinct differences. The PL of the stoichiometric material is dominated by free exciton emission, but the defect structures are characterized by broad deep luminescence bands of currently unknown origin.