Highly p-doped graphene obtained by fluorine intercalation
  We present a method for decoupling epitaxial graphene grown on SiC(0001) by intercalation of a layer of fluorine at the interface. The fluorine atoms do not enter into a covalent bond with graphene, but rather saturate the substrate Si bonds. This configuration of the fluorine atoms induces a remarkably large hole density of p \approx 4.5 \times 1013 cm-2, equivalent to the location of the Fermi level at 0.79 eV above the Dirac point ED . 
Andrew L. Walter, Ki-Joon Jeon, Aaron Bostwick, Florian Speck, Markus   Ostler, Thomas Seyller, Luca Moreschini, Yong Su Kim...
cond-mat.mtrl-sci