Effects of vacancy defects on the mechanical properties of graphene/hexagonal BN superlattice nanoribbons

Two kinds of vacancy defects, rhombic and square nanoholes, were produced in graphene/hexagonal BN (g/h-BN) superlattice nanoribbons by ion irradiation. The effects of the type (rhombus and square), area, number density and position of the nanoholes, and the period length of the nanoribbons on their mechanical properties were investigated by molecular dynamics simulation. The results show that the failure strength and strain of the nanoribbons are more sensitive to vacancy defects than is the Young`s modulus. The mechanical properties are insensitive to the period length of the nanoribbons and those with rhombus nanoholes have inferior mechanical properties to those with square nanoholes under the same conditions. The mechanical properties of the nanoribbons are largely affected by the positions of the nanoholes, such that they should be in the graphene and not in boron nitride as much as possible. By increasing the number density of the nanoholes, the toughness of the nanoribbons is increased.