Temperature Dependent Thermal Boundary Conductance of Monolayer MoS$_2$ by Raman Thermometry

TL;DR

This study measures how the thermal boundary conductance of monolayer MoS$_2$ varies with temperature using Raman thermometry, revealing its weak interface energy dissipation and the importance of optical absorption characterization.

Contribution

First to characterize the temperature-dependent optical absorption of monolayer MoS$_2$ above room temperature for accurate Raman thermometry.

Findings

TBC ~ 15 MW/m²K near room temperature

TBC increases as T^0.65 from 300 to 600 K

MoS$_2$ shows similar TBC with AlN and SiO$_2$ substrates

Abstract

The electrical and thermal behavior of nanoscale devices based on two-dimensional (2D) materials is often limited by their contacts and interfaces. Here we report the temperature-dependent thermal boundary conductance (TBC) of monolayer MoS$_2$ with AlN and SiO$_2$, using Raman thermometry with laser-induced heating. The temperature-dependent optical absorption of the 2D material is crucial in such experiments, which we characterize here for the first time above room temperature. We obtain TBC ~ 15 MWm$^-$$^2$K$^-$$^1$ near room temperature, increasing as ~ T$^0$$^.$$^6$$^5$ in the range 300 - 600 K. The similar TBC of MoS$_2$ with the two substrates indicates that MoS$_2$ is the "softer" material with weaker phonon irradiance, and the relatively low TBC signifies that such interfaces present a key bottleneck in energy dissipation from 2D devices. Our approach is needed to correctly perform Raman thermometry of 2D materials, and our findings are key for understanding energy coupling at the nanoscale.