Nanoscale Mapping of Strain-engineered Excitons in Monolayer WSe2
Abstract
Excitons in monolayer transition metal dichalcogenides (TMDs) are highly sensitive to external stimuli, allowing control of resonance energies and lifetimes through electric and magnetic fields, heterostructures, moire potentials and mechanical strain. Observations of single-photon emission (SPE) near sample edges, wrinkles, and strained nanobubbles have motivated strain-engineering aimed at realizing localized emitters in 2D materials. The origin of these emitters remains unclear and prior studies have relied on far-field spectroscopy with strain profiles inferred separately through topography, limiting direct correlation between local strain and excitonic response. We directly probe strain-modified excitonic spectra in monolayer WSe2 using cryogenic scattering-type scanning near-field optical microscopy (s-SNOM). We compare two strain-engineering techniques, nano-indentation and patterned substrates, used to produce SPEs. At 9 K, we spatially resolve exciton resonance shifts with sub-diffraction limit resolution, simultaneously measuring near-field optical response and topography. We observe that strain transferred from nano-indentation into a deformable polymer substrate differs from that produced by draping TMDs over patterned dielectric pillars. Adhesion and tearing during plastic deformation drive a compressive exciton blueshift, while draping produces dominant tensile strain. Comparing the strain model results to the experimentally observed energy shifts shows that the nano-indentation strain is over an order of magnitude smaller than previously inferred, due to puncturing of the fragile monolayer, whereas pillar-strained devices remain intact under more modest strain. These differences suggest SPE arises from complex, strain-mediated interactions rather than simple confinement potentials, establishing s-SNOM as a powerful probe of quantum emission in strained 2D materials.
Related
- Self-balancing luminescence kinetics of charged excitons in WS2 monolayer
- Magnetic-Field-Induced Darkening of Bright Excitons in a MoWSe2 Monolayer Alloy
- Room-temperature local strain control of moiré excitons in MoS2/WSe2 heterobilayers
- Orbital-engineered px,y-kagome lattice in a halogen monolayer
- Strain-induced structural transformations in hexagonal monolayer boron nitride. A density functional study
BibTeX
@misc{roche2026nanoscale,
title = {{Nanoscale Mapping of Strain-engineered Excitons in Monolayer WSe$_2$}},
author = {Anna S. Roche and Nicholas V. Proscia and Paul D. Cunningham and Kathleen M. McCreary and Dante J. O'Hara and Hsun Jen Chuang and Cory Cress and Collin Sanborn and Samuel W. LaGasse and Jose J. Fonseca and Jeremy T. Robinson and Takashi Taniguchi and Kenji Watanabe and John R. Schaibley and Brian J. LeRoy},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.19006},
eprint = {2610.19006},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.19006},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Nanoscale Mapping of Strain-engineered Excitons in Monolayer WSe_2
AU - Anna S. Roche
AU - Nicholas V. Proscia
AU - Paul D. Cunningham
AU - Kathleen M. McCreary
AU - Dante J. O'Hara
AU - Hsun Jen Chuang
AU - Cory Cress
AU - Collin Sanborn
AU - Samuel W. LaGasse
AU - Jose J. Fonseca
AU - Jeremy T. Robinson
AU - Takashi Taniguchi
AU - Kenji Watanabe
AU - John R. Schaibley
AU - Brian J. LeRoy
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2610.19006
UR - https://arxiv.org/abs/2610.19006
AB - Excitons in monolayer transition metal dichalcogenides (TMDs) are highly sensitive to external stimuli, allowing control of resonance energies and lifetimes through electric and magnetic fields, heterostructures, moire potentials and mechanical strain. Observations of single-photon emission (SPE) near sample edges, wrinkles, and strained nanobubbles have motivated strain-engineering aimed at realizing localized emitters in 2D materials. The origin of these emitters remains unclear and prior studies have relied on far-field spectroscopy with strain profiles inferred separately through topography, limiting direct correlation between local strain and excitonic response. We directly probe strain-modified excitonic spectra in monolayer WSe_2 using cryogenic scattering-type scanning near-field optical microscopy (s-SNOM). We compare two strain-engineering techniques, nano-indentation and patterned substrates, used to produce SPEs. At 9 K, we spatially resolve exciton resonance shifts with sub-diffraction limit resolution, simultaneously measuring near-field optical response and topography. We observe that strain transferred from nano-indentation into a deformable polymer substrate differs from that produced by draping TMDs over patterned dielectric pillars. Adhesion and tearing during plastic deformation drive a compressive exciton blueshift, while draping produces dominant tensile strain. Comparing the strain model results to the experimentally observed energy shifts shows that the nano-indentation strain is over an order of magnitude smaller than previously inferred, due to puncturing of the fragile monolayer, whereas pillar-strained devices remain intact under more modest strain. These differences suggest SPE arises from complex, strain-mediated interactions rather than simple confinement potentials, establishing s-SNOM as a powerful probe of quantum emission in strained 2D materials.
ER -