On the Formation of Graphene by Ge Intercalation of a 4H-SiC Surface

Abstract

The present communication focuses on the bilayer graphene formation on a Ge doped 4H-SiC surface. The 4H-SiC epilayer was grown by CVD with Germane (GeH4) as the dopant precursor. This easily leads to the formation of Ge islands as well as graphene on the 4H-SiC surface. The Ge island decorated surface was studied by Raman spectroscopy, XPS, and TEM. It was found that the bilayer graphene is free standing and that the native oxides act as a buffer layer on the surface, covering the Ge islands. The intensity variations of the Ge component in the XPS spectra indicate that Ge atoms can be buried in the SiC surface. The TEM analysis revealed that the graphene layers are in the form of flakes, which can also be rived vertically with the support of the Ge islands on SiC surface.