Analysis of Cobalt Intercalation under the Buffer Carbon Layer on a SiC(0001) Single Crystal

We analyze the synthesis of the buffer carbon layer on a SiC(0001) single crystal and its subsequent intercalation with cobalt atoms. It is shown using X-ray photoelectron spectroscopy that the intercalation is accompanied with the formation of a surface cobalt silicide alloy under the quasi-free graphene. The data measured using angle-resolved photoelectron spectroscopy demonstrate the presence of a Dirac cone near the Fermi level, which confirms the formation of quasi-free graphene as a result of intercalation. The morphology and homogeneity of the resulting system have been investigated using atomic force microscopy and Raman spectroscopy. The features of the graphene band structure on possible cobalt silicide alloys have been investigated using the density functional theory. The calculations of the chemical shift of the 2 p level of Si for cobalt silicides confirm the presence of CoSi and CoSi 2 components in X-ray photoelectron spectroscopy data. It is shown that the formation of quasi-free graphene with a linear dispersion of the π states is possible only on the CoSi surface. In view of the importance of investigation of graphene on insulating substrates as well as unique properties of graphene in contact with magnetic metals, we hope that this study will make a contribution to further realization of graphene in spintronics and nanoelectronics devices.