CHARACTERIZATION OF CUIN(GA)SE-2 THIN-FILMS - II - IN-RICH LAYERS

In-rich CuIn(Ga)Se-2 thin films are characterized by optical and elect rical measurements. The results are consistently explained in the Shkl ovskij/Efros model appropriate for highly defective and highly compens ated semiconductors. The dominant radiative recombination is of tail-i mpurity type at low temperatures and low excitation powers, and of ban d-impurity type at high temperatures and/or high excitation densities. The analysis of the data yields that the impurity content is in the o rder of 10(18) cm(-3) while the free carrier (hole) concentration at r oom temperature is in the order of 10(16) cm(-3). The impurity density increases with increasing deviation of the Cu/(In+Ga) ratio from stoi chiometry.