NANOIR FEATURED PUBLICATIONS

Energy Dissipation in Monolayer MoS₂ Electronics

August 4, 2017
Authors

E. Yalon, C. McClellan, K. Smithe, M. Rojo, R. Xu, S. Suryavanshi, A. Gabourie, C. Neumann, F. Xiong, A. Farimani, and E. Pop

Key points

  • Scanning thermal microscopy (SThM) reveals insights into energy dissipation of 2D semiconductors for future design of energy-efficient 2D electronics
  • Higher temperature sensitivity of SThM (<5 K), compared to Raman (~10K), allows the detection of temperature rise at lower power input and reduces the uncertainty of Raman measurement
  • High spatial and temperature resolution confirms MoS2 regions do not act as hot spots but rather shows uniform temperature rise with cooling on the edges

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 multilayered 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 MoS2 transistors. Using Raman thermometry, we simultaneously obtain temperature maps of the device channel and its substrate. This differential measurement reveals the thermal boundary conductance of the MoS2 interface with SiO2 (14 ± 4 MW m-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 nonuniformities of the MoS2 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.

A high spatial resolution temperature map of a MoS₂ channel using SThM shows an increase in temperature upon voltage being applied to the channel; temperature resolution measurement <5K.