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Strongly Bound Charge-Transfer Interface Excitons in Lateral Monolayer MoSe2-WSe2 Heterostructures
Vishal Suri1, Sakal Singla1, Suman Kumar Chakraborty2
1Department of Physics, Indian Institute of Technology (IIT) Jammu, 181221 Jammu, India.
Nano Letters
|July 17, 2026
Summary
Researchers explored dipolar charge-transfer interface excitons in transition-metal dichalcogenide heterostructures. They observed these unique excitons at sharp junctions in molybdenum selenide-tungsten selenide (MoSe2-WSe2) using photoluminescence and theory.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Lateral heterostructures of transition-metal dichalcogenide (TMD) monolayers with type-II band alignment can host dipolar charge-transfer interface excitons.
- Exploration of these excitons is limited due to challenges in creating clean, uniform lateral interfaces.
Purpose of the Study:
- To systematically investigate excitons in lateral monolayer MoSe2-WSe2 heterostructures with varying interface sharpness.
- To identify and characterize dipolar charge-transfer interface excitons at sharp junctions.
Main Methods:
- Low-temperature photoluminescence spectroscopy to probe excitonic signals.
- Synthesis of lateral MoSe2-WSe2 heterostructures with sharp and diffuse junctions.
- Ab initio many-body perturbation theory calculations to model exciton behavior.
Main Results:
- An additional spectral signal, attributed to dipolar charge-transfer excitons, was exclusively observed at sharp MoSe2-WSe2 junctions.
- Theoretical calculations confirmed the existence of stable, strongly bound dipolar charge-transfer excitons at the lateral interface, even with small band offsets.
Conclusions:
- Sharp lateral interfaces in MoSe2-WSe2 heterostructures facilitate the formation of dipolar charge-transfer interface excitons.
- Experimental photoluminescence signals at sharp junctions are consistent with theoretical predictions of these excitons.
Keywords:
Bethe−Salpeter equationGW approximationab initio many-body perturbation theorycharge transferchemical vapor depositionfirst-principles calculationsinterface excitonlateral heterostructurelow temperaturemonolayer transition-metal dichalcogenidephotoluminescence spectroscopytwo-dimensional materialMore Related Videos
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