Thermal Expansion Coefficient of Monolayer Molybdenum Disulfide Using Micro-Raman Spectroscopy
Name
NanoLetters06132019.pdf
Description
Accepted version
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1.68 MB
Format
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Checksum (MD5)
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Author(s)
Zhang, Lenan
Lu, Zhengmao
Song, Youngsup
Zhao, Lin
Bhatia, Bikram
Bagnall, Kevin R
Wang, Evelyn N
Date Issued
2019
Journal
Nano Letters
Publisher
American Chemical Society (ACS)
Version
Author's final manuscript
Abstract
© 2019 American Chemical Society. Atomically thin two-dimensional (2D) materials have shown great potential for applications in nanoscale electronic and optical devices. A fundamental property of these 2D flakes that needs to be well-characterized is the thermal expansion coefficient (TEC), which is instrumental to the dry transfer process and thermal management of 2D material-based devices. However, most of the current studies of 2D materials' TEC extensively rely on simulations due to the difficulty of performing experimental measurements on an atomically thin, micron-sized, and optically transparent 2D flake. In this work, we present a three-substrate approach to characterize the TEC of monolayer molybdenum disulfide (MoS2) using micro-Raman spectroscopy. The temperature dependence of the Raman peak shift was characterized with three different substrate conditions, from which the in-plane TEC of monolayer MoS2 was extracted on the basis of lattice symmetries. Independently from two different phonon modes of MoS2, we measured the in-plane TECs as (7.6 ± 0.9) × 10-6 K-1 and (7.4 ± 0.5) × 10-6 K-1, respectively, which are in good agreement with previously reported values based on first-principle calculations. Our work is not only useful for thermal mismatch reduction during material transfer or device operation but also provides a general experimental method that does not rely on simulations to study key properties of 2D materials.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1021/ACS.NANOLETT.9B01829
