Abstract
Based on the monolayer growth mode of graphene sheets (2D crystal) by chemical vapor deposition (CVD) on a Cu surface, it should be possible to grow the 2D crystal embedded with single wall carbon nanocones (SWCNC) if nano-conical pits are pre-fabricated on the surface. However, a previous experiment showed that the growing graphene sheet can cross grain boundaries without bending, which seems to invalidate this route for growing SWCNCs. The criterion of Gibbs free energy was applied in the present work to address this issue, showing that the sheet can grow into the valley of a boundary if the boundary has a slope instead of a quarter-turn shape, and SWCNCs can be obtained by this route as long as the lower diameter of the pre-fabricated pit is larger than 1.6 nm and the deposition temperature is higher than 750 K.
Highlights
As a 2D crystal, graphene has vast applications
Molecular dynamics (MD) simulations indicated that single wall carbon nanocones (SWCNC) are stable even at 1500 K [6], and our previous work employing a statistical model showed that the cones can survive for 107 years at room temperature [7], which makes them potential candidates for future nanoscale devices
SWCNCs grow and we have to resort to the Gibbs free energy (GFE) criterion that states for an isobaric process, such as chemical vapor deposition (CVD) Cu growth, the geometry of smallerthe substrates.isHowever, realistic growth rate of graphene by CVD is too slow for MD to simulate, system tends to a structure of lower GFE
Summary
As a 2D crystal, graphene has vast applications. It would be highly interesting if single wall carbon nanocones (SWCNCs) can be growth in graphene sheets since SWCNCs have many extraordinary properties. If the quarter-turn boundary is replaced with a slope, the asimulations slope, the simulations show that the structure is a bent sheet which is stuck to the surface. MDsimulations simulationson onthe therelaxation relaxation of a piece of graphene sheet initially stuck to a quarter-turn boundary. Cu substrate of a piece of graphene sheet initially stuck to a quarter-turn boundary. The initial temperature has little effect on the bent graphene sheet became flat with a little vibration. When the mobile C atoms were initially assigned velocities of Maxwell distribution at 300 K, the bent sheet turned into a flat structure in about 50 ps. Temperature, and (b) the difference defined as G f − Gb for a given slope
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