Characterization of Intrinsic Defect Levels in CuInS2

Electrical and photoluminescence measurements have been carried out on chemical vapor transport grown CuInS2 single crystals in order to determine intrinsic defect levels in this material. Post-growth treatments, like annealing in vacuum, air, Cu-, In, and S-atmosphere were used to identify the observed electronic defect levels. Using these data, the formation energy of the intrinsic point defects, and the stoichiometry of the samples a band diagram for defect levels in CVT-grown CuInS2 single crystals is proposed. Moreover similarities and differences to related ternary chalcopyrite compounds, like CuInSe2 and CuGaSe2, are discussed and pointed out.