Probing and Tuning Strain-Localized Exciton Emission in 2D Material Bubbles at Room Temperature

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Monolayer transition metal dichalcogenides exhibit unique optical properties due to strain effects in nanoscale deformations like bubbles.
• Exciton confinement in these bubbles leads to phenomena such as single-photon generation and tunable emission spectra.

Purpose of the Study:

• To directly visualize exciton properties within WSe2 monolayer bubbles.
• To actively modify local strain and tune exciton emission.
• To establish a framework for nanoscale emission control.

Main Methods:

• Emission mapping and nanoindentation using a dielectric near-field probe.
• Detection of local emission spectra and lifetimes within individual bubbles.
• Statistical analysis of 67 bubbles to determine emission wavelength distribution.

Main Results:

• Revealed an intrinsic emission wavelength shift of approximately 40 nm in WSe2 bubbles.
• Demonstrated active tuning of exciton emission over a 50 nm range by modifying local strain.
• Identified an emission wavelength distribution centered around 780 nm.
• Confirmed the localized nature of strain-induced states through power-dependent studies and lifetime analysis.

Conclusions:

• Provided direct insights into strain-localized emission dynamics in bubbles.
• Established a robust framework for non-destructive, reversible, and predictable nanoscale emission control.
• Presented a potential pathway for developing next-generation tunable quantum optical sources.