Effect of S:Fe Molar Ratios on the Direct Formation of Nanocrystalline Pyrite FeS2 Thin Films by Chemical Spray Pyrolysis under a Low Substrate Temperature (< 300 °C) for Biosensor

The FeS2 films were deposited by using the spray pyrolysis method using mixed aqueous solutions of CH4N2S and FeCl3, with different S:Fe molar ratios. The homogeneous FeS2 nanocrystalline films with good crystallinity were synthesized. The structure, composition, and properties of these films were very sensitive to the S:Fe molar ratios. The direct transition of the pyrite FeS2 films were about 0.9 - 1.25 eV. High absorption coefficients and suitable band gaps were observed. FeS2 thin films were synthesized for new biomaterial applications such as glucose.