Two Dimensional Phonon Transport in Graphene

We present thermal conductivity measurements of monolayer graphene exfoliated on a silicon dioxide substrate at different temperatures. A nanofabricated resistance thermometer device is developed to measure the thermal conductance of graphene and supporting 300nm thick SiO$_{2}$ layer, which allows us to extract the thermal conductivity of graphene while supported on this layer. The measured value is as high as 600 W/mK near room temperature, which is lower than that of suspended graphene, 1500-5800 W/mK, but still higher than those of metal interconnects. Theoretical calculations show that the strong interface-scattering of flexural modes across the graphene-oxide interface is responsible for the decreased value.