Electronic structure of epitaxial graphene layers on SiC: effect of the substrate.
A strong substrate-graphite bond is found in the first all-carbon layer by density functional theory calculations and x-ray diffraction for few graphene layers grown epitaxially on SiC. This first layer is devoid of graphene electronic properties and acts as a buffer layer. The graphene nature of the film is recovered by the second carbon layer grown on both the (0001) and (0001[over]) 4H-SiC surfaces. We also present evidence of a charge transfer that depends on the interface geometry. Hence the graphene is doped and a gap opens at the Dirac point after three Bernal stacked carbon layers are formed.
Varchon
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Institut Néel, CNRS-UJF, BP 166, 38042 Grenoble Cedex 9, France.
Feng
R
R
Hass
J
J
Li
X
X
Nguyen
B Ngoc
BN
Naud
C
C
Mallet
P
P
Veuillen
J-Y
JY
Berger
C
C
Conrad
E H
EH
Magaud
L
L