Effects of Monovacancy on Thermal Properties of Bilayer Graphene Nanoribbons by Molecular Dynamics Simulations

The monovacancy defect effect on thermal conductivity of bilayer graphene nanoribbons (BGNs) was investigated using non-equilibrium molecular dynamics (NEMD) simulations in this work. Our results demonstrate that the presence of monovacancy defect in BGNs reduces their thermal transport properties significantly. The major finding of this work shows that the calculated thermal conductivity reduces approximately linearly with the raise of monovacancy concentration. In contrast to the temperature-dependent thermal conductivity in perfect BGNs, the thermal conductivity of defected BGNs first increases and then decreases with the increasing temperature. In addition, when the difference in the monovacancy density between two layers is larger, the thermal conductivity of BGNs is higher. We also calculated the phonon density of states, phonon relaxation time and participation ratio to provide a deeper understanding of the simulation results. Our investigation confirms that the BGNs-based nano-devices could be applied in thermal management by defect engineering.