Cl-intercalated graphene on SiC: Influence of van der Waals forces
PSE Division, KAUST - Thuwal 23955-6900, Kingdom of Saudi Arabia
Received: 9 October 2012
Accepted: 14 January 2013
The atomic and electronic structures of Cl-intercalated epitaxial graphene on SiC are studied by first-principles calculations. By increasing the Cl concentration, doping levels from n-type to slightly p-type are achieved on the SiC(0001) surface, while a wider range of doping levels is possible on the SiC(000) surface. We find that the Cl atoms prefer bonding to the substrate rather than to the graphene. By varying the Cl concentration the doping level can be tailored. Consideration of van der Waals forces improves the distance between the graphene and the substrate as well as the binding energy, but it is not essential for the formation energy. For understanding the doping mechanism the introduction of non-local van der Waals contributions to the exchange correlation functional is shown to be essential.
PACS: 73.22.Pr – Electronic structure of graphene / 71.20.Tx – Fullerenes and related materials; intercalation compounds / 63.20.dk – First-principles theory
© EPLA, 2013