چكيده به لاتين
The first known two dimensional material in the world is graphene; a C-C hexagonal structure. 2D boron nitride which is composed of nitrogen and boron, with similar structure is in the second row after graphene. The same properties and very similar structure between graphene and boron nitride, along with their differences, cause interesting properties out of their hybridization and this topic is intrigued by many researchers, today.
From electronic point of view, graphene is a metal or semi-metal and boron nitride is a dielectric (band gap= 5.9 ev). Hybridization of the two materials opens band gap in graphene which has wide applications in field-effect graphene transistors. In this paper, firstly mechanical properties of pure graphene and boron nitride have been investigated. Then, effect of the interface structure on the mechanical properties of hybrid graphene boron nitride was studied. Young modulus, strain and tensile strength of the samples were measured in this research.
In here, by using molecular dynamics simulation, the mechanical properties of butt-joined hybrid graphene-boron nitride (BN) sheets in the presence of various defects have been investigated. For this purpose, two types of defects including circular and square holes have been created in the examined specimens. The effects of increasing the hole diameter, hole length (circular and square), number of holes and also the effect of different locations of such defects in hybrid graphene-boron nitride sheets on their mechanical properties have been analyzed and discussed. At the nanoscale, various defects such as cracks and cavities can surely appear in the structure of 2D materials during their synthesis by the CVD technique. The formation of these flaws in nanomaterials can substantially alter their electrical, chemical and mechanical properties. In the present work, the effects of three types of crack defects (one along the armchair direction and two in the zigzag direction) on the mechanical properties of hybrid graphene-boron nitride (BN) nanosheets have been investigated. The obtained results indicate that hybrid nanostructures with longitudinal cracks display more desirable mechanical properties than those with the two types of transverse cracks. These greater mechanical properties can be attributed to the direction of tensile stress; when a crack in a nanostructure is aligned with the direction of tension, the defective nanostructure displays better mechanical properties. The various types of defects in a hybrid graphene-boron nitride nanostructure have a much lower effect on its Young’s modulus value than its failure strength and strain.
Keywords: Graphene, Boron Nitride, Graphene-Boron Nitride Hybrid, mechanical properties and thermal properties
