Thin film Iron Pyrite synthesized by sulfurization of Iron Oxide for application in photovoltaics

Iron Pyrite (FeS₂) is considered as a promising candidate for photovoltaic application because of its suitable band-gap, very high light absorption coefficient and the abundance of the component elements in the earth´s crust. The problem however is that Iron Sulfide has several coexisting phases. Even with the same stoichiometry, it may have two different phases such as pyrite and marcasite. In this report, a phase pure iron pyrite is fabricated on a plain glass and molybdenum coated glass in an atmospheric pressure chemical vapor deposition system (APCVD) by annealing sputtered iron oxide (Fe₂O₃) in sulfur environment (elemental sulfur) at temperatures higher than 350°C. X-ray Diffraction measurement showed only pyrite phase and energy dispersive spectroscopy (EDS) showed 1:2 ratio for iron to sulfur. Depth profile using X-ray Photoelectron Spectroscopy showed a full conversion of iron oxide into pyrite. Increasing the temperature beyond 350°C, grain size got bigger, but pyrrhotite phase with very low resistivity started to appear.