Optical dipole orientation of interlayer excitons in 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>MoSe</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mo>−</mml:mo><mml:msub><mml:mi>WSe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
 heterostacks

Sigl, Lukas; Troue, Mirco; Katzer, Manuel; Selig, Malte; Sigger, Florian; Kiemle, Jonas; Brotons‐Gisbert, Mauro; Watanabe, Kenji; Taniguchi, Takashi; Gerardot, Brian D.; Knorr, Andreas; Wurstbauer, Ursula; Holleitner, Alexander W.

doi:10.1103/physrevb.105.035417

Cited by 29 publications

(25 citation statements)

References 45 publications

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“…B. In agreement with recent observations [73], we assume that the z-components of the dipoles d z ϕ µ r=0 ≈ 0 in the TMDCs, and consider the molecular dipoles to be aligned with respect to the inplane coordinate, i.e. d 12 z ≈ 0.…”

Section: Rytova-keldysh Type Greens Dyadementioning

confidence: 60%

Impact of dark excitons on Förster-type resonant energy transfer between dye molecules and atomically thin semiconductors

et al. 2023

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Interfaces of dye molecules and two-dimensional transition metal dichalcogenides (TMDCs) combine strong molecular dipole excitations with high carrier mobilities in semiconductors. Förster type energy transfer is one key mechanism for the coupling between both constituents. We report microscopic calculations of a spectrally resolved Förster induced transition rate from dye molecules to a TMDC layer. Our approach is based on microscopic Bloch equations which are solved selfconsistently together with Maxwells equations. This approach allows to incorporate the dielectric environment of a TMDC semiconductor, sandwiched between donor molecules and a substrate. Our analysis reveals transfer rates in the meV range for typical dye molecules in closely stacked structures, with a non-trivial dependence of the Förster rate on the molecular transition energy resulting from unique signatures of dark, momentum forbidden TMDC excitons.

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Section: Rytova-keldysh Type Greens Dyadementioning

confidence: 60%

Impact of dark excitons on Förster-type resonant energy transfer between dye molecules and atomically thin semiconductors

et al. 2023

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“…This is much smaller than the photon wavelength 933 nm and, therefore, we expect the dipole approximation to be entirely valid in this case. Since the optical dipole of IX is in-plane [39], the coupling between the cavity mode and the different trapped IX sites is described by the Tavis-Cummings model…”

mentioning

confidence: 99%

Lasing of Moiré Trapped MoSe$_2$/WSe$_2$ Interlayer Excitons Coupled to a Nanocavity

Qian¹,

Troue²,

Figueiredo³

et al. 2023

Preprint

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Moiré trapped interlayer excitons (IXs) in heterobilayer transition metal dichalcogenides currently attract strong interest due to their potential for non-classical light generation, coherent spin-photon interfaces and exploring novel correlated phases of electrons. Here, we report lasing of moiré trapped IXs by integrating a pristine hBN-encapsulated MoSe2/WSe2 heterobilayer in a high-Q (> 10 4 ) nanophotonic cavity. We control the detuning between the IX line and the cavity mode with a magnetic field and measure the dipolar coupling strength to the cavity mode to be 78 ± 4 µeV, fully consistent with the 82 µeV predicted by theory. The emission from the cavity mode shows clear threshold-like behaviour. We observe a superlinear power dependence accompanied by a narrowing of the linewidth as the distinct features of lasing. The onset and prominence of these threshold-like behaviours are significant at resonance whilst weak off-resonance. Our results show that a lasing transition can be induced in interacting moiré trapped IXs with macroscopic coherence extending over the lengthscale of the cavity mode. Such systems raise interesting perspectives for low-power switching and synaptic nanophotonic devices using 2D materials.

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“…With interlayer hopping, holes in layer 2 can form a bright exciton with electrons in CB2 in layer 1. Such spatially indirect excitons have been reported in other multilayer TMDCs like MoS 2 , − MoSe 2 , WSe 2 and heterobilayers. , But so far they have not been observed in any room temperature PL spectra, likely due to the low quantum efficiency in those indirect gap multilayer TMDCs. In bilayer MoTe 2 , the energy separation (Δ E 1 ) between the two lowest conduction bands at the K valley is 27 meV at 0 strain, close to the separation (33.9 meV) we see between P 1 and P 2 in Figure b.…”

Section: Resultsmentioning

confidence: 84%

Strain-Induced Indirect-to-Direct Bandgap Transition, Photoluminescence Enhancement, and Linewidth Reduction in Bilayer MoTe₂

Dong

Binder

et al. 2023

ACS Nano

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Two-dimensional (2D) layered materials provide an ideal platform for engineering electronic and optical properties through strain control because of their extremely high mechanical elasticity and sensitive dependence of material properties on mechanical strain. In this paper, a combined experimental and theoretical effort is made to investigate the effects of mechanical strain on various spectral features of bilayer MoTe 2 photoluminescence (PL). We found that bilayer MoTe 2 can be converted from an indirect to a direct bandgap material through strain engineering, resulting in a photoluminescence enhancement by a factor of 2.24. Over 90% of the PL comes from photons emitted by the direct excitons at the maximum strain applied. Importantly, we show that strain effects lead to a reduction of the overall linewidth of PL by as much as 36.6%. We attribute the dramatic decrease of linewidth to a strain-induced complex interplay among various excitonic varieties such as direct bright excitons, trions, and indirect excitons. Our experimental results on direct and indirect exciton emission features are explained by theoretical exciton energies that are based on first-principles electronic band structure calculations. The consistent theory-experimental trend shows that the enhancement of PL and the reduction of linewidth are the consequences of the increasing direct exciton contribution with the increase of strain. Our results demonstrate that strain engineering can lead to a PL quality of the bilayer MoTe 2 comparable to that of the monolayer counterpart. The additional benefit of a longer emission wavelength makes the bilayer MoTe 2 more suitable for silicon-photonics integration due to the reduced silicon absorption.

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Optical dipole orientation of interlayer excitons in MoSe2−WSe2 heterostacks

Cited by 29 publications

References 45 publications

Impact of dark excitons on Förster-type resonant energy transfer between dye molecules and atomically thin semiconductors

Impact of dark excitons on Förster-type resonant energy transfer between dye molecules and atomically thin semiconductors

Lasing of Moiré Trapped MoSe$_2$/WSe$_2$ Interlayer Excitons Coupled to a Nanocavity

Strain-Induced Indirect-to-Direct Bandgap Transition, Photoluminescence Enhancement, and Linewidth Reduction in Bilayer MoTe₂

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Optical dipole orientation of interlayer excitons in MoSe2−WSe2 heterostacks

Cited by 29 publications

References 45 publications

Impact of dark excitons on Förster-type resonant energy transfer between dye molecules and atomically thin semiconductors

Impact of dark excitons on Förster-type resonant energy transfer between dye molecules and atomically thin semiconductors

Lasing of Moiré Trapped MoSe$_2$/WSe$_2$ Interlayer Excitons Coupled to a Nanocavity

Strain-Induced Indirect-to-Direct Bandgap Transition, Photoluminescence Enhancement, and Linewidth Reduction in Bilayer MoTe2

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Strain-Induced Indirect-to-Direct Bandgap Transition, Photoluminescence Enhancement, and Linewidth Reduction in Bilayer MoTe₂