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

TL;DR

This paper demonstrates a method to visualize and actively tune exciton emission in 2D material bubbles at room temperature, revealing strain-induced wavelength shifts and enabling controllable quantum light sources.

Contribution

It introduces a direct visualization and active tuning approach for strain-localized exciton emission in 2D bubbles, advancing nanoscale emission control techniques.

Findings

Intrinsic emission wavelength shift of ~40 nm observed.

Active strain modification achieves 50 nm emission tuning.

Localized emission states exhibit saturation and lifetime changes.

Abstract

Excitons in 2D material bubbles-nanoscale deformations in atomically thin materials, typically exhibiting a dome-like shape-are confined by the strain effect, exhibiting extraordinary emission properties, such as single photon generation, enhanced light emission, and spectrally tunable excitonic states. While the strain profiles of these bubbles have been extensively studied, this work provides an approach (1) to directly visualize the associated exciton properties, revealing an intrinsic emission wavelength shift of approximately 40 nm, and (2) actively modify local strain, enabling further exciton emission tuning over a range of 50 nm. These are achieved by emission mapping and nanoindentation using a dielectric near-field probe, which enables the detection of local emission spectra and emission lifetimes within individual bubbles. Statistical analysis of 67 bubbles uncovers an emission wavelength distribution centered around 780 nm. Furthermore, saturation behavior in the power-dependent studies and the associated lifetime change reveal the localized nature of the strain-induced states. These findings provide direct insights into the strain-localized emission dynamics in bubbles and establish a robust framework for non-destructive, reversible, and predictable nanoscale emission control, presenting a potential avenue for developing next-generation tunable quantum optical sources.