Formation of Iron Silicides Under Graphene Grown on the Silicon Carbide Surface

The formation of iron silicide thin films under graphene grown on the silicon carbide surface is investigated. The thin films are synthesized by consecutive intercalation of iron and silicon atoms into the graphene. Experiments are carried out in situ in ultrahigh vacuum. The elemental composition and chemical state of the surface of prepared samples and their atomic structure are determined by low-energy electron diffraction and high-resolution X-ray photoelectron spectroscopy using synchrotron radiation. The thickness of deposited iron and silicon layers varies in the range of 0.1–2 nm, and the sample annealing temperature is varied from room temperature to 600°C. We show that intercalation of silicon into the graphene/Fe/SiC system leads to the formation of a layer of Fe–Si solid solution coated with the surface silicide Fe3Si. The films are effectively protected by graphene from exposure to ambient environment, which opens possibilities for their practical application.