In situ XRD study of mixed CuInSe2–CuInS2 formation Original Research Article

The formation of CuInS2–CuInSe2 alloy films from chalcogenisation of different precursors is investigated by in situ energy dispersive X-ray diffraction. A sequential synthesis procedure was used. Copper and indium (Cu/In=1.8) were sputtered on molybdenum coated soda-lime glass and selenium was introduced as a layer of elemental selenium or as a In2Se3 layer. Such prepared precursor films were then sulfurized in elemental sulfur vapor. The effects of the selenium precursors and the influence of sulfurization conditions on the resulting absorber films composition and properties were investigated. It is shown that the ternary phases in the final film were CuInS2, CuIn(Se,S)2, and CuInSe2 in the case of elemental Se precursor deposition and CuInS2, CuIn(Se,S)2 in the case of In2Se3 precursors. The differences in the formation path ways are investigated in detail.