Abstract
Heteroatom doping is an efficient way to modify the chemical and electronic properties of
graphene. In particular, boron doping is expected to induce a p-type conducting behavior
to pristine (undoped) graphene which could lead to diverse applications. However, the
experimental progress on atomic scale visualization and sensing properties of large-area
boron-doped graphene (BG) sheets is still very scarce. This work describes the controlled
growth of centimeter size, high-crystallinity BG sheets. Scanning tunneling microscopy and
spectroscopy are used to visualize the atomic structure and the local density of states
around boron dopants. It is confirmed that BG behaves as a p-type conductor and a unique
croissant-like feature is frequently observed within the BG lattice, which is caused by the
presence of B-C trimmers embedded within the hexagonal lattice. More interestingly, it is
demonstrated for the first time that BG exhibits unique sensing capabilities when
detecting toxic gases, such as NO2 and NH3 , being able to detect extremely low
concentrations (e.g. parts per trillion, parts per billion). This work envisions that other
attractive applications could now be explored based on as-synthesized BG.
