Photoluminescence as a tool for investigations of the junction region in Cu(In,Ga)Se2-based solar cells

We use different modes of photoluminescence (PL) technique to investigate recombination processes within the junction region of Cu(In,Ga)Se2-based solar cells. Components of the PL spectra associated with recombination within the junction region and in the bulk are distinguished. We provide arguments for the interpretation of the double diode effect in the p+ layer model basing on a close correlation between fill factor, PL intensity, and changes of space charge distribution induced by blue and red illumination.