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Misorientation-Angle-Dependent Phase Transformation in van der Waals Multilayers via Electron-Beam Irradiation
Un Jeong Kim1, Hyangsook Lee2,3, Woojin Lee4
1Imaging Device Lab., Samsung Advanced Institute of Technology, Suwon, 443-803, Republic of Korea.
Advanced Materials (Deerfield Beach, Fla.)
|March 25, 2018
Summary
The stacking order of molybdenum disulfide (MoS2) layers dictates phase transformation. AA stacking enables transformation from semiconducting to metallic phases, while other stacking orders do not.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Van der Waals materials exhibit unique properties dependent on layer thickness and misorientation angle.
- The effect of misorientation angle on phase transformation in these materials remains largely unexplored.
Purpose of the Study:
- To investigate the influence of stacking order on the phase transformation of molybdenum disulfide (MoS2) multilayers.
- To determine if misorientation angle affects the structural phase transition under electron-beam irradiation.
Main Methods:
- In situ electron-beam irradiation of MoS2 multilayers.
- In situ transmission electron microscopy (TEM) for structural analysis.
- Analysis of different stacking configurations (AA' vs. non-AA').
Main Results:
- An AA'-stacked MoS2 bilayer transforms from the 2H semiconducting phase to the 1T' metallic phase under electron-beam irradiation.
- Non-AA' stacked MoS2 does not exhibit this phase transformation.
- Collective sliding of chalcogen atoms facilitates the transformation in AA' stacking, but is hindered in non-AA' stacking.
Conclusions:
- The stacking configuration is critical for inducing phase transformation in MoS2 multilayers.
- AA' stacking promotes the semiconducting-to-metallic phase transition due to favorable atomic motion.
- Non-AA' stacking suppresses this transition due to interlocked atoms and weaker van der Waals interactions.
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