In-rich films were subjected to post-growth Cu diffusion. Photoluminescence investigations revealed a transition from the commonly observed broad band near to 0.94eV, to a much sharper peak near to 0.98eV, under low excitation density. This recombination appeared at a slightly higher energy than the usually cited recombination that was near to 0.96eV. The excitation power-dependence suggested that the observed peak was related to a donor-acceptor pair band, as indicated by an 0.0025eV/decade shift in the peak-energy and the temperature-dependence of the photoluminescence signal. An activation energy of 0.04eV was extracted from an Arrhenius plot of the luminescence intensity. When the data were analyzed within the framework of the most recent theoretical predictions, a possible candidate for the center was deduced to be [CuIn-Cui].

Investigation of Post-Growth Cu Diffusion in In-rich CuInSe2 Films O.Ka, H.Alves, I.Dirnstorfer, T.Christmann, B.K.Meyer: Thin Solid Films, 2000, 361-362, 263-7