The defect properties of as-grown and annealed CuInSe2, CuIn0.5Ga0.5Se2 and CuGaSe2 single crystals which had been grown by means of chemical vapour transport were studied by performing photoluminescence, Hall effect and resistivity measurements. Various observed defect levels were attributed to intrinsic defect states. The activation energies and concentrations of these defects were compared among the 3 compounds. It was found that the properties of as-grown p-type samples were dominated by Cu and Se vacancies. The activation energies of these defects decreased slightly with increasing In content. A huge difference was observed in the properties of a donor level which was introduced by annealing in the presence of the corresponding group-III element. This defect level was much shallower, and more easily formed, in In-containing compounds. It was tentatively attributed to a VCu-IIICu defect pair.

Effect of the Ga-Content on the Defect Properties of Cu(In,Ga)Se2 Single Crystals J.H.Schön, C.Kloc, E.Bucher: Thin Solid Films, 2000, 361-362, 411-4