Energy Dissipation in Monolayer MoS$_2$ Electronics

TL;DR

This study measures temperature distribution in monolayer MoS$_2$ transistors, revealing higher-than-expected thermal boundary conductance and showing that inhomogeneities have limited impact on self-heating, informing future energy-efficient 2D electronics design.

Contribution

First direct spatially resolved temperature measurements in functioning 2D MoS$_2$ transistors, revealing key thermal boundary conductance values and effects of inhomogeneity.

Findings

Thermal boundary conductance of MoS$_2$ interface is 14 ± 4 MW/m$^2$K.

Inhomogeneities like small bilayer regions do not significantly affect self-heating.

Thermal boundary conductance is higher than previously thought, near the low end of solid-solid interfaces.

Abstract

The advancement of nanoscale electronics has been limited by energy dissipation challenges for over a decade. Such limitations could be particularly severe for two-dimensional (2D) semiconductors integrated with flexible substrates or multi-layered processors, both being critical thermal bottlenecks. To shed light into fundamental aspects of this problem, here we report the first direct measurement of spatially resolved temperature in functioning 2D monolayer MoS$_2$ transistors. Using Raman thermometry we simultaneously obtain temperature maps of the device channel and its substrate. This differential measurement reveals the thermal boundary conductance (TBC) of the MoS$_2$ interface (14 $\pm$ 4 MWm$^-$$^2$K$^-$$^1$) is an order magnitude larger than previously thought, yet near the low end of known solid-solid interfaces. Our study also reveals unexpected insight into non-uniformities of the MoS$_2$ transistors (small bilayer regions), which do not cause significant self-heating, suggesting that such semiconductors are less sensitive to inhomogeneity than expected. These results provide key insights into energy dissipation of 2D semiconductors and pave the way for the future design of energy-efficient 2D electronics.