First-principles calculations based on density functional theory are performed on graphene/BN and BN bilayers to investigate the effect of the strain on their energy gaps. For the graphene/BN bilayer, the bands have characteristic graphenelike features with a small band gap at K. Application of strain modulates the band gap, whose magnitude depends on the strength of interaction between constituent monolayers. For the BN bilayer, on the other hand, a large band gap is predicted, which remains nearly the same for small strains. The increased inhomogeneity in charge density of different carbon sublattices due to a stronger interplanar interaction is the cause of the predicted variation in the band gap with strains applied along the perpendicular direction in the graphene/BN bilayer.
Category: 2011
Catalyst-free formation of vertically-aligned carbon nanorods as induced by nitrogen incorporation
Catalyst-free-CNx-Nanorods2011
We found that nitrogen incorporation can induce the formation of vertically-aligned hydro-
genated carbon nanorods without the use of catalysts. These nitrogen incorporated hydro-
genated carbon nanorods (CNx:H) were synthesized by radio-frequency plasma-enhanced
chemical vapor deposition (PE-CVD). We have evaluated the structural and chemical evolu-
tion of these CNx:H films as a function of the deposition duration by using high-resolution
scanning electron microscopy (HRSEM), high-resolution transmission electron microscopy
(HRTEM), Fourier transform infrared spectroscopy (FTIR), and Auger electron spectroscopy.
Results indicate that the incorporation of nitrogen is responsible to the formation of these
nanorods. The alignment of the nanorods is enhanced at longer deposition period and is
correlated to the increase in nitrogen contents and isonitrile bonds [–N„C] in the nano-
rods. The growth mechanism of this catalyst-free formation of nitrogen incorporated car-
bon nanorods is proposed.