Effect of Precursor Concentration on Structural and Morphological Properties of Iron Pyrite Thin Films

The cubic FeS2 (Pyrite) films are prepared by chemical bath deposition method (CBD) at different iron ion precursor concentrations that varying from 2.0 M to 0.5 M. X-ray diffractograms revealed that the presence of (110) plane, corresponding to marcasite structure, and (106) and (304) planes, corresponding to FeS (Triolite) phase are observed along with the pure pyrite phase (200) at higher concentrations of iron. The films deposited at 1.0 M concentration has strong (200) and (023) planes related to pure pyrite phase. This is confirmed by the Raman measurements. It is observed that the molar concentration of the precursor plays an important role in controlling the morphology of the films. FTIR spectra shows the existence of –OH, -CH stretching of –CH2 vibrations modes. The optical absorption coefficient is > 104 cm-1 in the visible spectrum, indicating that this material is exploitable as solar cell absorber and found to be optically isotropic. The studies revealed that the precursor concentration of Iron has a significant effect on the behaviour of FeS2 films. A detailed analysis of the results with appropriate discussion is presented.