Vacancy Interlayer Migration in Multi-layered Graphene

Graphene has innumerous applications due to its exceptional properties. Various defects that may be introduced into the graphene lattice during synthesis and/or post-treatments are known have significantly impact on these properties. So engineering graphene by introducing or annealing of defects is an important technology to achieve desired properties for various applications. Therefore a comprehensive understanding on the behavior of defects in graphene is critically important. Here, interlayer migration of the vacancies in multi-layered graphene (MLG) was investigated by density functional tight-binding molecular dynamic simulations and first principle calculations. Our study reveals that, although the direct vacancy migration between neighboring graphene layers (NGLs) is prohibited by a very high barrier up to $\sim$ 7 eV, the interaction between vacancies or vacancy and holes in NGLs can greatly reduce the barrier to $\sim$ 3 eV and expedites the migration process. Our study reveals a new mechanism of the defect self-healing in MLG and multi-walled carbon nanotubes and it can be used to engineer desired graphene materials.