Heat Conduction across Monolayer and Few-Layer Graphenes

We report the thermal conductance G of Au/Ti/graphene/SiO2 interfaces (graphene layers 1 < n < 10) typical of graphene transistor contacts. We find G ~ 25 MW m-2 K-1 at room temperature, four times smaller than the thermal conductance of a Au/Ti/SiO2 interface, even when n = 1. We attribute this reduction to the thermal resistance of Au/Ti/graphene and graphene/SiO2 interfaces acting in series. The temperature dependence of G from 50 < T < 500 K also indicates that heat is predominantly carried by phonons through these interfaces. Our findings indicate that metal contacts can limit not only electrical transport, but also thermal dissipation from sub-micron graphene devices.