Tunable thermal transport properties of graphene by single-vacancy point defect

Abstract

Graphene, a representative two-dimensional nanomaterial, possess great potential in the field of nanoelectronics. However, the defects which are usually unavoidable in the fabrication of graphene may cause significant thermal effects in real applications. Thus, the effective and precise manipulation of thermal transport is critical for the practical applications of graphene-based electronic devices. In this paper, the effect of single-vacancy point defect on thermal transport properties of graphene was analyzed with non-equilibrium molecular dynamics (NEMD) method. We found that the existence of single-vacancy point defect can reduce the thermal conductivities of graphene. However, different from previous conclusions, the thermal conductivity of graphene depends not only on the defect density, but also on the topological configuration of defect. Our present results revealed that thermal conductivity of graphene with randomly distributed defects decreases monotonously with the increase of defect density. On the contrary, the thermal conductivity of graphene with regularly distributed defects expresses obvious non-monotonicity for the same case. This phenomenon was furthermore explained by performing the analysis of phonon properties. These results indicate that the precise manipulation on the thermal conductivity of nanodevices can be realized by regulating the topological configuration of defect on graphene. These understandings will provide important references for the development of nanoelectronic devices.