Thermal conductance at the graphene-SiO2 interface measured by optical pump-probe spectroscopy

We have examined the interfacial thermal conductance {\sigma}int of single and multi-layer graphene samples prepared on fused SiO2 substrates by mechanical exfoliation of graphite. By using an ultrafast optical pump pulse and monitoring the transient reflectivity on the picosecond time scale, we obtained an average {\sigma}int of 5,000 W/cm2K for the graphene-SiO2 system. We observed significant variation in {\sigma}int between individual samples, but found no systematic dependence on the thickness of the graphene layers.