Substrate coupling suppresses size dependence of thermal conductivity in supported graphene

Thermal conductivity kappa of both suspended and supported graphene has been studied by using molecular dynamics simulations. An obvious length dependence is observed in kappa of suspended singlelayer graphene (SLG), while kappa of supported SLG is insensitive to the length. The simulation result of room temperature kappa of supported SLG is in good agreement with the experimental value. In contrast to the decrease in kappa induced by inter-layer interaction in suspended few-layer graphene (FLG), kappa of supported FLG is found to increase rapidly with the layer thickness, reaching about 90% of that of bulk graphite at six layers, and eventually saturates at the thickness of 13.4 nm. More interestingly, unlike the remarkable substrate dependent kappa in SLG, the effect of substrate on thermal transport is much weaker in FLG. The underlying physics is investigated and presented.Chemistry, MultidisciplinaryNanoscience & NanotechnologyMaterials Science, MultidisciplinaryPhysics, AppliedSCI(E)EI20ARTICLE2532-536