For investigations of the defect spectra of CuInSe2 epitaxial thin films are grown on GaAs (0 0 1) wafers using metal organic vapor phase epitaxy. The photoluminescence spectra for p-type Cu-rich ([Cu]/[In] >1.05) CuInSe2 are dominated by one donor acceptor pair transition at 0.972 eV. For slightly Cu-poor and stoichiometric samples a free to bound transition at 0.992 eV is observed. Also an exciton emission could be detected at E-FX = 1.032 eV indicating a bandgap of E-G = 1.038 eV at 10 K. These results can be combined in a defect model for CuInSe2 containing two acceptors states with 40 and 60 meV and a compensating 6 meV donor state. (C) 2003 Elsevier Science B.V. All rights reserved.