Cathodoluminescence of Cu(In,Ga)Se2 thin films used in high-efficiency solar cells

Cathodoluminescence spectroscopy and spectrum imaging are employed to investigate Cu(In,Ga)Se-2 (CIGS) thin films used in high-efficiency solar cells. We have found a nonuniform spatial distribution for the photon energy. The shift by decade of the emission spectrum is also found to depend systematically on the location of excitation. In addition, the photon energy at grain boundaries is not affected by the external excitation. A model for radiative recombination to be applied to these chalcopyrite compounds should explain these results, and some suggestions are considered. (C) 2003 American Institute of Physics.