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 approximate to 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 C from 50 <= T <= 500 K also indicates that heat is predominantly carried by phonons through these interfaces. Our findings suggest that metal contacts can limit not only electrical transport but also thermal dissipation from submicrometer graphene devices.