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Indirect Excitons and Trions in MoSe2/WSe2 van der Waals Heterostructures
E V Calman1, L H Fowler-Gerace1, D J Choksy1
1Department of Physics, University of California at San Diego, La Jolla, California 92093, United States.
Nano Letters
|February 19, 2020
Summary
Indirect excitons (IXs) in MoSe2/WSe2 heterostructures exhibit unique properties. Researchers observed neutral and charged IXs, paving the way for high-temperature excitonic devices and quantum gases.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Optics
Background:
- Indirect excitons (IXs) are bosons controllable by voltage and light, explored in GaAs heterostructures.
- Low binding energies in GaAs limit IX quantum Bose gases and devices to low temperatures.
- Van der Waals transition-metal dichalcogenide (TMD) heterostructures offer high binding energies for IXs.
Purpose of the Study:
- Investigate indirect excitons (IXs) in MoSe2/WSe2 heterostructures.
- Explore the potential for high-temperature excitonic quantum gases and devices.
- Characterize single-exciton phenomena and few-particle complexes in TMDs.
Main Methods:
- Fabrication and optical characterization of MoSe2/WSe2 heterostructures.
- Analysis of indirect exciton luminescence spectra.
- Temperature-dependent measurements of IX properties.
Main Results:
- Identified two IX luminescence lines corresponding to neutral and charged IXs.
- Measured a binding energy for indirect charged excitons (trions) close to theoretical predictions (28 meV).
- Achieved narrow IX luminescence line widths (down to 4 meV) and enhanced intensity in localized spots.
Conclusions:
- MoSe2/WSe2 heterostructures enable high-temperature studies of IXs.
- Demonstrated the potential for creating excitonic devices and quantum gases at elevated temperatures.
- Reported on the realization of high-quality indirect excitons with potential for advanced quantum applications.
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