Optical properties of Cu-richCuInSe2thin films prepared by the selenization of Cu/In/Cu alloys in aH2Seatmosphere have been studied by photoluminescence (PL) spectroscopy. PL spectra of as-grown samples were dominated by transitions due to intrinsic defect levels, which are ascribed toVIn(24 meV),CuIn(75 meV), andCui(53 meV). After chemical etching (10&percent; KCN), emission lines attributed to free and bound excitonic emissions and their LO phonon replica became visible. Accurate analysis of the peak positions revealed values of 4.3 meV, 1.0441 eV, and 28.7 meV for the binding energy of the free exciton, the band gap, and the value for the LO phonon, respectively. ©1997 American Institute of Physics.