Thin Solid Films, Vol.403-404, 71-75, 2002
Composition of CuInS2 thin films prepared by spray pyrolysis
CuInS2 films were prepared by spray pyrolysis technique using CuCl2. InCl3 and SC(NH2)(2) as initial chemicals. The content of Cl, O, C and N impurities in sprayed CuInS2 films were measured by EDS, WDS, RBS and organic elemental analysis. The growth temperatures of 260-280degreesC result in Cl. C, N content of 8 mass% and the impurity phases contain SCN, CN, NH, SO4 groups as identified by FTIR. The increase in the growth temperature up to 380degreesC decreases the concentration of Cl. C, N to 1-2 mass%, concurrently leading to oxidation of inorganic and organic phases resulting in 0 content of 16.7 at.%. The content of impurities originated from precursors is mainly controlled by the growth temperature and in less extent by the Cu/In ratio in spray solution as Cu-rich solutions result in the films with reduced content of organic residues. Thermal treatments in reducing atmospheres at 450degreesC improves the crystallinity of the films while annealing in flowing H-2 effectively reduces the content of Cl and O impurities.