Atomic Diffusional Transport in Graphene

Graphene is a two-dimensional material, a single-atomic-layer sheet of carbon, with extraordinary mechanical and optoelectronic properties that have the potential to enable numerous applications, such as in electronic device and nanocomposite fabrication. Graphene’s properties can be further tailored through chemical functionalization and defect engineering. In this work, a systematic analysis based on molecular-dynamics simulations has been conducted to explore atomic diffusion along graphene nanoribbon (GNR) edges and edges of nanopores in graphene. Such atomic diffusion facilitates the migration of nanopores, as well as GNR edge relaxation and pattern formation at high temperature. The effects of the edge types (armchair and zigzag) on the atomic diffusivity have been investigated. The Arrhenius temperature dependence of such edge diffusivity has been established and the activation energy barriers for edge atomic diffusion have been calculated. Finally, the diffusion mechanisms have been analyzed further by constructing the underlying optimal atomic migration paths through nudged elastic band (NEB) calculations. This work will contribute to our fundamental understanding of defect dynamics in graphene structures at high temperature and aid in the improvement of defect engineering strategies in graphene and graphene derivatives.