Synthesis of Stoichiometric FeS2 through Plasma-Assisted Sulfurization of Fe2O3 Nanorods

Pyrite (FeS2) thin films were synthesized using a H2S plasma to sulfurize hematite (Fe2O3) nanorods deposited by chemical bath deposition. The high S activity within the plasma enabled a direct solid-state transformation between the two materials, bypassing S-deficient contaminant phases (Fe1–xS). The application of plasma dramatically enhanced both the rate of conversion and the quality of the resulting material; stoichiometric FeS2 was obtained at a moderate temperature of 400 °C using a chalcogen partial pressure 105 cm–1 in the visible range. Room-temperature conductivity of FeS2 films was on the order of 10–4 S cm–1 and approximately doubled under calibrated solar illumination.