Tunable thermal conductivity along graphene/hexagonal boron-nitride polycrystalline heterostructures

Abstract.

Atomic layers of graphene and hexagonal boron-nitride (h-BN) are two-dimensional materials with very similar atomic structures. Recent experimental advances guarantee the possibility of making graphene/h-BN heterostructures, using the chemical vapour deposition technique which aims to build more advanced materials with tuneable electronic, mechanical and thermal properties. In this study, we investigate the in-plane thermal conductivity of the graphene/h-BN heterostructures by using the atomistic-continuum multi-scale method. In this regard at the first step, we carried out molecular dynamic simulation of polycrystalline films with nano-sized grains in atomic scale. Next, based on the results provided from the atomic scale, we developed a finite-element model for a larger-grained material to evaluate the effective thermal conductivity of macroscopic samples. Current study results reveal the feasibility of tuning of thermal conductivity and heat transfer on graphene/h-BN heterostructures by controlling the grain size and percentage of h-BN atoms in the structures. In addition, the effects of grain boundaries on the thermal conductivity at various scales are also addressed. Our findings in this study provide good vision regarding the thermal conductivity of the graphene/h-BN heterostructure.