Local atomic structure of Cu(In x Ga1−x )Se2 (x = 0.25, 0.5, and 0.75) systems for solar cells

Abstract

The local atomic structure of thin surface layers of crystalline quasi-binary Cu(In x Ga1−x )Se2 solid solutions was studied by SIMS and EXAFS techniques. The SIMS method showed that the elemental composition of the sample changes most significantly in thin layers at a depth of 5–10 nm; in deeper layers, the component concentrations correspond to the bulk values. The EXAFS method in the x-ray fluorescence mode showed that the results obtained are in agreement with the assumption that quaternary crystalline quasi-binary Cu(In x Ga1−x )Se2 solid solutions exhibit local disorder while average long-range order is detected from x-ray diffraction data.