Mechanical properties of hybrid graphene and hexagonal boron nitride sheets as revealed by molecular dynamic simulations

Molecular dynamic simulations are performed to investigate the mechanical properties of hybrid graphene and hexagonal boron nitrogen (h-BN) sheet with the concentration of BN ranging from 0% to 100%. We find that Young's modulus of the hybrid sheet decreases with increasing concentration of BN, irrespective of BN shapes and distributions. However, a little mixing of h-BN and graphene can result in a noticeable drop in the yield strength of the hybrid sheet. In addition, the hybrid sheet exhibits strong plasticity behaviour during the tensile loading, which is not observed in pure graphene and BN sheets. We further demonstrate that this behaviour can be interpreted by the fact that the interface between the BN domain and graphene governs the failure mechanism of the hybrid sheet, which can be approximated by the classical Griffith model. Our results suggest that the mechanical properties of the hybrid graphene-BN sheet should be considered carefully when evaluating its whole performance when it is used in bandgap-engineered applications such as electronics and optics.