Large trion binding energy in monolayer WS$_2$ via strain-enhanced electron-phonon coupling

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Main Authors: Waheed, Yunus, Shit, Sumitra, Surendran, Jithin T, Prasad, Indrajeet D, Watanabe, Kenji, Taniguchi, Takashi, Kumar, Santosh
Format: Preprint
Published: 2024
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author Waheed, Yunus
Shit, Sumitra
Surendran, Jithin T
Prasad, Indrajeet D
Watanabe, Kenji
Taniguchi, Takashi
Kumar, Santosh
author_facet Waheed, Yunus
Shit, Sumitra
Surendran, Jithin T
Prasad, Indrajeet D
Watanabe, Kenji
Taniguchi, Takashi
Kumar, Santosh
contents Transition metal dichalcogenides and related layered materials in their monolayer and a few layers thicknesses regime provide a promising optoelectronic platform for exploring the excitonic- and many-body physics. Strain engineering has emerged as a potent technique for tuning the excitonic properties favorable for exciton-based devices. We have investigated the effects of nanoparticle-induced local strain on the optical properties of exciton, $X^0$, and trion, $X^\text{-}$, in monolayer WS$_2$. Biaxial tensile strain up to 2.0% was quantified and verified by monitoring the changes in three prominent Raman modes of WS$_2$: E${^1_{2g}}$($Γ$), A$_{1g}$, and 2LA(M). We obtained a remarkable increase of 34 meV in $X^\text{-}$ binding energy with an average tuning rate of 17.5 $\pm$ 2.5 meV/% strain across all the samples irrespective of the surrounding dielectric environment of monolayer WS$_2$ and the sample preparation conditions. At the highest tensile strain of $\approx$2%, we have achieved the largest binding energy $\approx$100 meV for $X^\text{-}$, leading to its enhanced emission intensity and thermal stability. By investigating strain-induced linewidth broadening and deformation potentials of both $X^0$ and $X^\text{-}$ emission, we elucidate that the increase in $X^\text{-}$ binding energy is due to strain-enhanced electron-phonon coupling. This work holds relevance for future $X^\text{-}$-based nano-opto-electro-mechanical systems and devices.
format Preprint
id arxiv_https___arxiv_org_abs_2412_10114
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Large trion binding energy in monolayer WS$_2$ via strain-enhanced electron-phonon coupling
Waheed, Yunus
Shit, Sumitra
Surendran, Jithin T
Prasad, Indrajeet D
Watanabe, Kenji
Taniguchi, Takashi
Kumar, Santosh
Mesoscale and Nanoscale Physics
Materials Science
Optics
Transition metal dichalcogenides and related layered materials in their monolayer and a few layers thicknesses regime provide a promising optoelectronic platform for exploring the excitonic- and many-body physics. Strain engineering has emerged as a potent technique for tuning the excitonic properties favorable for exciton-based devices. We have investigated the effects of nanoparticle-induced local strain on the optical properties of exciton, $X^0$, and trion, $X^\text{-}$, in monolayer WS$_2$. Biaxial tensile strain up to 2.0% was quantified and verified by monitoring the changes in three prominent Raman modes of WS$_2$: E${^1_{2g}}$($Γ$), A$_{1g}$, and 2LA(M). We obtained a remarkable increase of 34 meV in $X^\text{-}$ binding energy with an average tuning rate of 17.5 $\pm$ 2.5 meV/% strain across all the samples irrespective of the surrounding dielectric environment of monolayer WS$_2$ and the sample preparation conditions. At the highest tensile strain of $\approx$2%, we have achieved the largest binding energy $\approx$100 meV for $X^\text{-}$, leading to its enhanced emission intensity and thermal stability. By investigating strain-induced linewidth broadening and deformation potentials of both $X^0$ and $X^\text{-}$ emission, we elucidate that the increase in $X^\text{-}$ binding energy is due to strain-enhanced electron-phonon coupling. This work holds relevance for future $X^\text{-}$-based nano-opto-electro-mechanical systems and devices.
title Large trion binding energy in monolayer WS$_2$ via strain-enhanced electron-phonon coupling
topic Mesoscale and Nanoscale Physics
Materials Science
Optics
url https://arxiv.org/abs/2412.10114