Thermal conductivity of suspended pristine graphene measured by Raman spectroscopy

Abstract

The thermal conductivity of suspended single-layer graphene was measured as a function of temperature using Raman scattering spectroscopy on clean samples prepared directly on a prepatterned substrate by mechanical exfoliation without chemical treatments. The temperature at the laser spot was monitored by the frequency of the Raman 2$D$ band of the Raman scattering spectrum, and the thermal conductivity was deduced by analyzing heat diffusion equations assuming that the substrate is a heat sink at ambient temperature. The obtained thermal conductivity values range from $~$1800 W m${}^{\ensuremath{-}1}$K${}^{\ensuremath{-}1}$ near 325 K to $~$710 W m${}^{\ensuremath{-}1}$K${}^{\ensuremath{-}1}$ at 500 K.