Quasi-Freestanding Graphene on SiC(0001) by Ar-Mediated Intercalation of Antimony: A Route Toward Intercalation of High-Vapor-Pressure Elements

A novel strategy for the intercalation of antimony (Sb) under the (6 square root of 3) x (6 square root of 3) R 30 deg reconstruction, also known as buffer layer, on SiC(0001) is reported. Using X-ray photoelectron spectroscopy, low-energy electron diffraction, and angle-resolved photoelectron spectroscopy, it is demonstrated that, while the intercalation of the volatile Sb is not possible by annealing the Sb-coated buffer layer in ultrahigh vacuum, it can be achieved by annealing the sample in an atmosphere of Ar, which suppresses Sb desorption. The intercalation leads to a decoupling of the buffer layer from the SiC(0001) surface and the formation of quasi-freestanding graphene. The intercalation process paves the way for future studies of the formation of quasi-freestanding graphene by intercalation of high-vapor-pressure elements, which are not accessible by previously known intercalation techniques, and thus provides new avenues for the manipulation of epitaxial graphene on SiC.