Effect of Local Terrace on Structure and Mechanics of Graphene Grain Boundary

Abstract

In this study, the effects of local terrace of the substrate on the structure and mechanical properties of graphene grain boundaries (GBs) during CVD growth have been explored by phase field crystal (PFC) modeling and molecular dynamics (MD) simulations. It is found the GBs are significantly disturbed for weak surface disturbance with bulge height of only 3.4 A. The distance between GBs and bulge plays an important role in determining the morphologies of GBs, and the aperiodic and curved GBs can be observed which is attributed to several representative structures, like 5-6|6-7, 5-6-7 defects and GBs deflection. In general, there are four fracture modes for GBs with weak surface disturbance depending on the existence of 5-6-7 and 5-6|6-7 defects. While for strong surface disturbance with bulge height of 10 A, the interaction between topological defects at bulged graphene and GBs will locally offset nearby 5-7 dislocation pairs and there are two fracture modes depending on the structural integrality of GBs....