PHOTOLUMINESCENCE OF CUINS2 THIN-FILMS AND SOLAR-CELLS MODIFIED BY POSTDEPOSITION TREATMENTS

The photoluminescence of CuInS2 thin films and solar cells is investig ated as a function of postdeposition treatments for different temperat ures and excitation intensities. Annealing in hydrogen atmosphere caus es an increase of PL intensity at 1.445 eV by more than a factor of 10 0, while subsequent annealing in oxygen or air ambient passivates this transition, which is ascribed to a donor-acceptor pair recombination between a sulphur vacancy and a copper vacancy. A defect mechanism is suggested that assumes the passivation of sulphur vacancies by oxygen in grain surfaces which can be activated by hydrogen annealing. (C) 19 97 American Institute of Physics.