Tunable infrared light emission from MoS2/WSe2 heterostructures

Karni, Ouri; Barré, Elyse; Lau, Sze Cheung; Gillen, Roland; Yue, Eric; Gal, Lior; Yaffe, Tzach; Kim, Bumho; Watanabe, Kenji; Taniguchi, Takashi; Orenstein, Meir; Maultzsch, Janina; Barmak, K.; Page, Ralph H.; Heinz, Tony F.

doi:10.1364/cleo_si.2020.sm1q.1

Cited by 39 publications

(82 citation statements)

References 8 publications

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“…The enhanced lifetime for the misaligned sample could be an indication for the absence of the radiative decay channel as it was reported recently. 25 The difference in lifetime between quasi-2H and quasi-3R can then be explained by the same reasoning as the enhanced transfer. Since the charge transfer via a phonon-assisted tunneling process can be amplified by the spatial overlap of the involved wave functions, 6,28 the same should hold for the reversed process of interlayer exciton recombination: A stronger spatial coincidence facilitates the recombination resulting then in a reduced lifetime.…”

Section: Resultsmentioning

confidence: 93%

“…17 Recently, also momentum-space direct K−K photolumines-cence at ≈1.0 eV has been observed for well-aligned MoS 2 / WSe 2 heterostructures. 25 In the present study, we want to elucidate the corresponding ultrafast dynamics in dependence of the stacking angle for three selected stacking angles: 9°( referred to as quasi-3R), 52°(quasi-2H), and 16°( misaligned).…”

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confidence: 99%

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Ultrafast Charge-Transfer Dynamics in Twisted MoS₂/WSe₂ Heterostructures

et al. 2021

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Two-dimensional transition metal dichalcogenides offer a fascinating platform for creating van der Waals heterojunctions with exciting physical properties. Because of their typical type-II band alignment, photoexcited electrons and holes can separate via interfacial charge transfer. Furthermore, the relative crystallographic alignment of the individual layers in these heterostructures represents an important degree of freedom. Based on both effects, various fascinating ideas for applications in optoelectronics and valleytronics have been suggested. Despite its utmost importance for the design and efficiency of potential devices, the nature and the dynamics of ultrafast charge transfer are not yet well understood. This is mainly because the charge transfer can be surprisingly fast, usually faster than the temporal resolution of previous experimental approaches. Here, we apply time- and polarization-resolved second-harmonic imaging microscopy to investigate the charge-transfer dynamics for three MoS2/WSe2 heterostructures with different stacking angles at a previously unattainable time resolution of ≈10 fs. For 1.70 eV excitation energy, electron transfer from WSe2 to MoS2 is found to depend considerably on the stacking angle with the fastest transfer time observed to be as short as 12 fs. At 1.85 eV excitation energy, ultrafast hole transfer from MoS2 to hybridized states at the Γ-point and to the K-points of WSe2 has to be considered. Surprisingly, the corresponding decay dynamics show only a minor stacking-angle dependence indicating that radiative recombination of momentum-space indirect Γ-K excitons becomes the dominant decay route for all samples.

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Section: Resultsmentioning

confidence: 93%

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confidence: 99%

Ultrafast Charge-Transfer Dynamics in Twisted MoS₂/WSe₂ Heterostructures

et al. 2021

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“…Van der Waals stacking of those monolayer TMDs can provide a valid platform to explore rich physical processes including charge transfer, 9 many-body interactions, 10 coupled spin and valley physics, 11 and moirésuperlattices. 12 In particular, interlayer excitons (IXs) can be formed in the van der Waals stacked TMD heterobilayers 13,14 and carry the valley information. 15,16 Compared to the picosecond time scale of exciton valley depolarization in monolayer TMDs arising from the strong Coulomb interactions, 17 previous studies have revealed the nanosecond time scale of IXs in MoSe 2 /WSe 2 15,18 and MoS 2 / MoSe 2 19 and even extending to the microsecond time scale by applying an external magnetic field, 20 thus beneficial to the IXbased valleytronic devices 21 and low-threshold lasing.…”

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confidence: 99%

Robust Interlayer Coupling in Two-Dimensional Perovskite/Monolayer Transition Metal Dichalcogenide Heterostructures

et al. 2020

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Interlayer excitons have been extensively studied in monolayer transition metal dichalcogenide (TMD) heterobilayers mainly due to the long lifetime, which is beneficial for a wide range of optoelectronic applications. To date, the majority of investigations of interlayer excitons in TMD heterobilayers have been focusing on the geometric arrangement of structures, spin–valley lifetime, and interlayer valley excitons with interlayer hopping rules. Nevertheless, interlayer excitons in TMD heterobilayers strongly depend on the local atomic registry and coupling strength, which increase the complexity of the device fabrication. Here, we report pronounced interlayer exciton emission in two-dimensional (2D) perovskite/monolayer TMD heterostructures without the need of thermal annealing or specific geometric arrangements, and the interlayer exciton emission is rather general among 2D perovskites and monolayer TMDs. Such interlayer exciton emission completely dominates the emission spectrum at 78 K regardless of the stacking sequence, suggesting the robust interlayer coupling in 2D perovskite/monolayer TMD heterostructures. Furthermore, the interlayer exciton emission shows a large blue-shift with increasing laser intensity due to the repulsive dipole–dipole interaction and can persist above 220 K. Importantly, the interlayer exciton emission also possesses robust circular polarization in chiral 2D perovskite/monolayer WSe2 heterostructures, which can be applied to manipulate the valley degree of freedom for valleytronic devices. Our findings would provide a favorable platform to explore interlayer coupling and related physical processes in 2D perovskites and TMDs and further provoke more investigations into the understanding and controlling of excitonic effects and associated optoelectronic applications in van der Waals heterostructures over a broad-range spectral response.

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“…[6] Karni et al reproduced this direct interlayer exciton transition between the K valleys. [81] Their the oretical model from ab initio calculations suggested that the Γ point states hybridization rendered the Γ-K transition to be a mixed one (with inter and intralayer), giving rise to interlayer excitons with a weakened dipole moment.…”

Section: Tunable Wavelength From Near-ir To Mid-irmentioning

confidence: 99%

Interlayer Excitons in Transition Metal Dichalcogenide Semiconductors for 2D Optoelectronics

et al. 2022

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Tunable infrared light emission from MoS2/WSe2 heterostructures

Abstract: We report light emission around 1200 nm from a vertical heterostructure consisting of M0S2 and WSe2 monolayers. The emission, arising from the fundamental interlayer exciton, can be tuned by nearly 100 nm by electrical gating.

Cited by 39 publications

References 8 publications

Ultrafast Charge-Transfer Dynamics in Twisted MoS₂/WSe₂ Heterostructures

Ultrafast Charge-Transfer Dynamics in Twisted MoS₂/WSe₂ Heterostructures

Robust Interlayer Coupling in Two-Dimensional Perovskite/Monolayer Transition Metal Dichalcogenide Heterostructures

Interlayer Excitons in Transition Metal Dichalcogenide Semiconductors for 2D Optoelectronics

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Tunable infrared light emission from MoS2/WSe2 heterostructures

Abstract: We report light emission around 1200 nm from a vertical heterostructure consisting of M0S2 and WSe2 monolayers. The emission, arising from the fundamental interlayer exciton, can be tuned by nearly 100 nm by electrical gating.

Cited by 39 publications

References 8 publications

Ultrafast Charge-Transfer Dynamics in Twisted MoS2/WSe2 Heterostructures

Ultrafast Charge-Transfer Dynamics in Twisted MoS2/WSe2 Heterostructures

Robust Interlayer Coupling in Two-Dimensional Perovskite/Monolayer Transition Metal Dichalcogenide Heterostructures

Interlayer Excitons in Transition Metal Dichalcogenide Semiconductors for 2D Optoelectronics

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Ultrafast Charge-Transfer Dynamics in Twisted MoS₂/WSe₂ Heterostructures

Ultrafast Charge-Transfer Dynamics in Twisted MoS₂/WSe₂ Heterostructures