Effect of nanoscale defects on the thermal conductivity of graphene

There are remarkable theoretical efforts geared towards understanding the impact of fabrication-induced defects on the operational behaviour of a single layer graphene. These studies have been focused mainly on atomic defects, while nanoscale pinholes and patches of two layers thick (bilayer) attached on a monolayer graphene are inevitable during the synthesis process. In this work the influence of these nanoscale defects on the graphene thermal conductivity is studied via non-equilibrium molecular dynamics simulations. The thermal conductivity of a single layer zigzag and armchair oriented graphene is modelled capturing the effect of voids and bilayer imperfections. A single layer graphene sheet with a size of 50 nm × 10 nm is analysed having an elliptical defect of up to 6 nm (major axis). Our results exhibit a reduction of over 20% in thermal conductivity with increasing temperature and about 75% drop with increasing void size. The decrease in the thermal conductivity is 15% for the single layer graphene with a bilayer defect of 6 nm in diameter. This study demonstrates a dramatic influence of defect shape on the thermal conductivity of graphene, where defects with elliptical shapes demonstrate a higher thermal transfer in graphene compared to circular ones. This work provides a guideline of how to quantify the effect of fabrication induced defects on thermal conductivity of graphene.