Embedding foreign atoms or molecules in graphene has become the key approach in its functionalization and is intensively used for tuning its structural and electronic properties. Here, we present an efficient method based on chemical vapor deposition for large scale growth of boron-doped graphene (B-graphene) on Ni(111) and Co(0001) substrates using carborane molecules as the precursor. It is shown that up to 19 at. % of boron can be embedded in the graphene matrix and that a planar C–B sp2 network is formed. It is resistant to air exposure and widely retains the electronic structure of graphene on metals. The large-scale and local structure of this material has been explored depending on boron content and substrate. By resolving individual impurities with scanning tunneling microscopy we have demonstrated the possibility for preferential substitution of carbon with boron in one of the graphene sublattices (unbalanced sublattice doping) at low doping level on the Ni(111) substrate. At high boron content the honeycomb lattice of B-graphene is strongly distorted, and therefore, it demonstrates no unballanced sublattice doping.
The authors acknowledge Saint Petersburg State University for Research Grants 11.37.634.2013 and 11.50.202.2015, RFBR (Grant No. 14-02-31150), and BMBF (Grant No. 05K12OD3). We acknowledge Helmholtz Zentrum Berlin für Materialien und Energie for support within bilateral Russian German Laboratory program. MMO and EVC acknowledge the Tomsk State University Academic D.I. Mendeleev Fund Program (Research Grant No. 8.1.05.2015).