Thermal conductivity of suspended pristine graphene measured by Raman spectroscopy

TL;DR

This study measures the thermal conductivity of suspended pristine graphene across a temperature range using Raman spectroscopy, revealing high thermal conductivity values that decrease with increasing temperature.

Contribution

It provides direct measurements of graphene's thermal conductivity as a function of temperature using a non-invasive Raman technique on clean, suspended samples.

Findings

Thermal conductivity decreases from ~1800 W/mK at 325 K to ~710 W/mK at 500 K.

Raman spectroscopy effectively monitors temperature and heat diffusion in graphene.

The method avoids chemical treatments, preserving sample integrity.

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 $\sim$1800 Wm$^{-1}$K$^{-1}$ near 325 K to $\sim$710 Wm$^{-1}$K$^{-1}$ at 500 K.