Chowdhury, T and Chatterjee, S and Das, D and Timokhin, I and Núñez, PD and Gokul, AM and Chatterjee, S and Majumdar, K and Ghosh, P and Mishchenko, A and Rahman, A (2024) Brightening of dark excitons in WS2 via tensile strain-induced excitonic valley convergence. In: Physical Review B, 110 (8).
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Abstract
Transition-metal dichalcogenides (TMDs) host tightly bound electron-hole pairs - excitons - which can be either optically bright or dark based on spin and momentum selection rules. In tungsten-based TMDs, a momentum-forbidden dark exciton is the energy ground state, and therefore, it strongly affects the emission properties. In this work, we brighten the momentum-forbidden dark exciton by placing monolayer tungsten disulfide on top of nanotextured substrates, which imparts tensile strain, modifying its electronic band structure. This enables phonon-assisted exciton scattering between momentum valleys, thereby brightening momentum-forbidden dark excitons. In addition to offering a tuning knob for light-matter interactions in two-dimensional materials, our results pave the way for designing ultrasensitive strain-sensing devices based on TMDs. © 2024 American Physical Society.
Item Type: | Journal Article |
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Publication: | Physical Review B |
Publisher: | American Physical Society |
Additional Information: | The copyright for this article belongs to the publisher. |
Keywords: | Excited states; Excitons; Germanium compounds; Indium phosphide; Layered semiconductors; Phonon scattering; Photons; Tungsten compounds; Wide band gap semiconductors, Bound electrons; Dark excitons; Electron hole pairs; Emission properties; Energy; Excitonics; Selection Rules; Strain induced; Transition metal dichalcogenides (TMD); Tungsten disulfide, Tensile strain |
Department/Centre: | Division of Electrical Sciences > Electrical Communication Engineering |
Date Deposited: | 29 Aug 2024 06:25 |
Last Modified: | 29 Aug 2024 06:25 |
URI: | http://eprints.iisc.ac.in/id/eprint/85966 |
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