Cathodoluminescence studies of Cu(In,Ga)Se2 thin-films

We investigate the microstructure of Cu(In,Ga)Se-2 thin films. The absorber layers are grown by coevaporation of the constituent elements according to the three-stage process. They have different sodium contents and sodium sources, leading to different preferred grain orientations. A transmission electron microscope equipped with a cathodoluminescence spectrometer serves to analyze the electronic behavior of grain boundaries and structural defects. Contrasts in panchromatic cathodoluminescence images at grain boundaries and structural defects indicate an enhanced nonradiative recombination of charge carriers localized at these defects.