Comprehensive insights into point defect and defect cluster formation in CuInSe2

The concentration of native point defects in CuInSe2powder material as a function of stoichiometry has been experimentally determined by neutron powderdiffraction. A correlation between the Cu/In ratio and the density of VCu as well as InCu has been established and their concentrations are quantified. It is demonstrated, that assuming the spontaneous formation of defect pairs, the density of native point defects is reduced significantly by an order of magnitude. The functionality of a solar device, assuming same conditions like in the analyzed material, may be explained by a neutralization due to the formation of electrically inactive defect complexes.