Gate-Voltage Control of Quantum Yield in Monolayer Transition-Metal Dichalcogenide

Стріха, М. В.; Kurchak, Anatolii I.; Morozovska, Anna N.

doi:10.1103/physrevapplied.13.014040

Cited by 6 publications

(6 citation statements)

References 22 publications

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“…Plots of QY versus G and the PL spectra of other samples are provided in Figures S5b and S14− S16, and details for the QY measurement of 1L-WS 2 are described in the Supporting Information. At low exciton densities under NEGB, the QY of both samples showed a slight increase due to the depletion of excess charges 20 and electrostatic defect passivation, 21,36,62 which is in line with our theoretical model. Upon increasing G, the threshold G values for the QY drop are higher for sample B than for sample A and with NEGB than without NEGB; the lowest occurs at 2 × 10 15 cm −2 s −1 for sample A without NEGB, and the highest occurs at 1 × 10 17 cm −2 s −1 for sample B with NEGB.…”

Section: Resultssupporting

confidence: 89%

“…In addition, owing to the atomically thin thickness of 2D TMDs, electric gate bias can significantly affect the PL properties of these materials. , The immediate role of gate bias is modulating the charge density and, consequently, the relative population of exciton complexes such as neutral excitons, trions, and biexcitons, which directly affects the QY of 1L-TMDs. ,, It has been previously shown that a simple negative gate bias on 1L-MoS 2 or 1L-WS 2 could greatly increase the QY at low exciton densities; however, a severe decrease in the QY still occurred with increasing exciton density because of a strong EEA contribution . Gate bias has also been used to control the energy of interlayer excitons of heterostacked bilayers of 1L-TMDs , via the Stark effect.…”

Section: Introductionmentioning

confidence: 99%

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Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS₂ by Proximal Metal Plate and Negative Electric Bias

Tran,

Lee,

Roy

et al. 2023

ACS Nano

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The efficiency of light emission is a critical performance factor for monolayer transition metal dichalcogenides (1L-TMDs) for photonic applications. While various methods have been studied to compensate for lattice defects to improve the quantum yield (QY) of 1L-TMDs, exciton–exciton annihilation (EEA) is still a major nonradiative decay channel for excitons at high exciton densities. Here, we demonstrate that the combined use of a proximal Au plate and a negative electric gate bias (NEGB) for 1L-WS2 provides a dramatic enhancement of the exciton lifetime at high exciton densities with the corresponding QY enhanced by 30 times and the EEA rate constant decreased by 80 times. The suppression of EEA by NEGB is attributed to the reduction of the defect-assisted EEA process, which we also explain with our theoretical model. Our results provide a synergetic solution to cope with EEA to realize high-intensity 2D light emitters using TMDs.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS₂ by Proximal Metal Plate and Negative Electric Bias

Tran,

Lee,

Roy

et al. 2023

ACS Nano

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“…Ref reported that accumulation of charge outside of the neutrality point in 1L-WSe 2 leads to a decrease in luminescence quantum efficiency. This change is attributed to doping-induced effects, such as increases in Auger-like nonradiative recombination . As such, when doping by the beam is higher, the decrease in the CL intensity is larger.…”

Section: Resultsmentioning

confidence: 99%

“…This change is attributed to doping-induced effects, such as increases in Auger-like nonradiative recombination. 59 As such, when doping by the beam is higher, the decrease in the CL intensity is larger.…”

Section: Assessment Of Vdw-hs Quality Through Sem-clmentioning

confidence: 96%

Nanoscale Cathodoluminescence and Conductive Mode Scanning Electron Microscopy of van der Waals Heterostructures

Ramsden,

Sarkar,

Wang

et al. 2023

ACS Nano

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van der Waals heterostructures (vdW-HSs) integrate dissimilar materials to form complex devices. These rely on the manipulation of charges at multiple interfaces. However, at present, submicrometer variations in strain, doping, or electrical breakages may exist undetected within a device, adversely affecting macroscale performance. Here, we use conductive mode and cathodoluminescence scanning electron microscopy (CM-SEM and SEM-CL) to investigate these phenomena. As a model system, we use a monolayer WSe2 (1L-WSe2) encapsulated in hexagonal boron nitride (hBN). CM-SEM allows for quantification of the flow of electrons during the SEM measurements. During electron irradiation at 5 keV, up to 70% of beam electrons are deposited into the vdW-HS and can subsequently migrate to the 1L-WSe2. This accumulation of charge leads to dynamic doping of 1L-WSe2, reducing its CL efficiency by up to 30% over 30 s. By providing a path for excess electrons to leave the sample, near full restoration of the initial CL signal can be achieved. These results indicate that the trapping of charges in vdW-HSs during electron irradiation must be considered, in order to obtain and maintain optimal performance of vdW-HS devices during processes such as e-beam lithography or SEM. Thus, CM-SEM and SEM-CL form a toolkit through which nanoscale characterization of vdW-HS devices can be performed, allowing electrical and optical properties to be correlated.

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“…Considering recombination kinetics of excitonic species in 2D semiconductors, the enhancement of PL QY could be simply caused by the suppression of the dimmer excitonic complexes and the promotion of the brighter ones. [ 173,175,193,211–213 ] This postulation can be extended to any material system with excitonic features. If recombination modes of all excitonic complexes are known, PL QY of the system can be enhanced by encouraging the formation of species with a tendency to recombine radiatively; and vice versa.…”

Section: Strategies To Enhance the Brightness Of Monolayer Tmdcsmentioning

confidence: 99%

Bright and Efficient Light‐Emitting Devices Based on 2D Transition Metal Dichalcogenides

et al. 2023

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2D monolayer transition metal dichalcogenides (TMDCs) show great promise for the development of next‐generation light‐emitting devices owing to their unique electronic and optoelectronic properties. The dangling‐bond‐free surface and direct‐bandgap structure of monolayer TMDCs allow for near‐unity photoluminescence quantum efficiencies. The excellent mechanical and optical characteristics of 2D TMDCs offer great potential to fabricate TMDC‐based light‐emitting diodes (LEDs) featuring good flexibility and transparency. Great progress has been made in the fabrication of bright and efficient LEDs with varying device structures. In this review, the aim is to provide a comprehensive summary of the state‐of‐the‐art progress made in the construction of bright and efficient LEDs based on 2D TMDCs. After a brief introduction to the research background, the preparation of 2D TMDCs used for LEDs is briefly discussed. The requirements and the corresponding challenges to achieve bright and efficient LEDs based on 2D TMDCs are introduced. Thereafter, various strategies to enhance the brightness of monolayer 2D TMDCs are described. Following that, the carrier‐injection schemes enabling bright and efficient TMDC‐based LEDs along with the device performance are summarized. Finally, the challenges and future prospects regarding the accomplishment of TMDC‐LEDs with ultimate brightness and efficiency are discussed.

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Gate-Voltage Control of Quantum Yield in Monolayer Transition-Metal Dichalcogenide

Cited by 6 publications

References 22 publications

Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS₂ by Proximal Metal Plate and Negative Electric Bias

Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS₂ by Proximal Metal Plate and Negative Electric Bias

Nanoscale Cathodoluminescence and Conductive Mode Scanning Electron Microscopy of van der Waals Heterostructures

Bright and Efficient Light‐Emitting Devices Based on 2D Transition Metal Dichalcogenides

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Gate-Voltage Control of Quantum Yield in Monolayer Transition-Metal Dichalcogenide

Cited by 6 publications

References 22 publications

Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS2 by Proximal Metal Plate and Negative Electric Bias

Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS2 by Proximal Metal Plate and Negative Electric Bias

Nanoscale Cathodoluminescence and Conductive Mode Scanning Electron Microscopy of van der Waals Heterostructures

Bright and Efficient Light‐Emitting Devices Based on 2D Transition Metal Dichalcogenides

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Product

Resources

About

Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS₂ by Proximal Metal Plate and Negative Electric Bias

Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS₂ by Proximal Metal Plate and Negative Electric Bias