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Updated: Apr 24, 2026

Fabricating van der Waals Heterostructures with Precise Rotational Alignment
Published on: July 5, 2019
Spectroscopic signatures for interlayer coupling in MoS2-WSe2 van der Waals stacking
Ming-Hui Chiu1, Ming-Yang Li, Wengjing Zhang
1Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia.
Mechanically stacked transition metal dichalcogenide (TMD) monolayers of MoS2 and WSe2 can be coupled by thermal treatment. This process creates van der Waals solids with enhanced interlayer interactions, confirmed by Raman and photoluminescence spectroscopy.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Transition metal dichalcogenides (TMDs) like MoS2 and WSe2 are crucial 2D materials.
- Stacking different TMD monolayers allows for novel heterostructures with unique electronic and optical properties.
- Achieving strong interlayer coupling in stacked TMDs is key to unlocking their potential.
Purpose of the Study:
- To investigate the interlayer coupling in mechanically stacked MoS2/WSe2 heterostructures.
- To determine the effect of thermal treatment on the coupling of TMD monolayers.
- To explore the formation of van der Waals solids from stacked TMDs.
Main Methods:
- Chemical vapor deposition (CVD) growth of triangular MoS2 and WSe2 monolayers.
- Mechanical stacking of MoS2 on WSe2 monolayers.
- Raman spectroscopy and photoluminescence (PL) studies.
- Thermal annealing at 300 °C.
Main Results:
- Initially weakly coupled stacked monolayers become strongly interacting after thermal treatment.
- The WSe2 A(2)1g Raman mode at 309 cm(-1) is sensitive to interlayer coupling.
- Interlayer excitonic emissions and shifts in MoS2 Raman modes (E″ at 286 cm(-1) and A(2)1g at 463 cm(-1)) indicate enhanced coupling.
Conclusions:
- Thermal treatment is an effective method to induce strong interlayer coupling in stacked TMD heterostructures.
- The resulting van der Waals solids exhibit enhanced interactions between MoS2 and WSe2 monolayers.
- Spectroscopic signatures confirm the formation of coupled TMD bilayers with potential for new optoelectronic applications.
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