Valley trion dynamics in monolayer 
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Gao, Feng; Gong, Yongji; Titze, Michael; Almeida, Raybel; Ajayan, Pulickel M.; Li, Hebin

doi:10.1103/physrevb.94.245413

Cited by 60 publications

(41 citation statements)

References 59 publications

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“…1(c)) with C = 1.45 shows good agreement with the data, providing a trion binding energy of 28 meV and a FWHM of 29 meV. The retrieved trion binding energies are consistent with previous reports 1,21,[25][26][27] . The aged sample shows a larger linewidth and a smaller trion contribution.…”

Section: Sample and Experimental Setupsupporting

confidence: 88%

Resonantly excited exciton dynamics in two-dimensional MoSe2 monolayers

et al. 2017

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We report on the exciton and trion density dynamics in a single layer of MoSe2, resonantly excited and probed using three-pulse four-wave mixing (FWM), at temperatures from 300 K to 77 K . A multi-exponential third-order response function for amplitude and phase of the heterodyne-detected FWM signal including four decay processes is used to model the data. We provide a consistent interpretation within the intrinsic band structure, not requiring the inclusion of extrinsic effects. We find an exciton radiative lifetime in the sub-picosecond range consistent to what has been recently reported 1 . After the dominating radiative decay, the remaining exciton density, which has been scattered from the initially excited bright radiative state into dark states of different nature by exciton-phonon scattering or disorder scattering, shows a slower dynamics, covering 10ps to 10ns timescales. This includes direct bright transitions with larger in-plane momentum, as well as indirect dark transitions to indirect dark states. We find that exciton-exciton annihilation is not relevant in the observed dynamics, in variance from previous finding under non-resonant excitation. The trion density at 77 K reveals a decay of the order of 1 ps, similar to what is observed for the exciton. After few tens of picoseconds, the trion dynamics resembles the one of the exciton, indicating that trion ionization occurs on this timescale.

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Section: Sample and Experimental Setupsupporting

confidence: 88%

Resonantly excited exciton dynamics in two-dimensional MoSe2 monolayers

et al. 2017

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“…The lack of oscillatory enhancement in X − is possibly due to its distinct radiative properties compared to X 0 , together with the availability of multiple formation pathways 35 (e.g., via the exciton-electron interaction following exciton relaxation 36 ). For X 0 , only those inside the light cone (k ω X 0 =c) can radiate.…”

Section: Resultsmentioning

confidence: 99%

Phonon-assisted oscillatory exciton dynamics in monolayer MoSe2

Chow

Jones

et al. 2017

npj 2D Mater Appl

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In monolayer semiconductor transition metal dichalcogenides, the exciton-phonon interaction strongly affects the photocarrier dynamics. Here, we report on an unusual oscillatory enhancement of the neutral exciton photoluminescence with the excitation laser frequency in monolayer MoSe 2 . The frequency of oscillation matches that of the M-point longitudinal acoustic phonon, LA(M), suggesting the significance of zone-edge acoustic phonons and hence the deformation potential in exciton-phonon coupling in MoSe 2 . Moreover, oscillatory behavior is observed in the steady-state emission linewidth and in time-resolved PLE data, which reveals variation with excitation energy in the exciton lifetime. These results clearly expose the key role played by phonons in the exciton formation and relaxation dynamics of two-dimensional van der Waals semiconductors.

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“…First, the trion binding energies are surprisingly large, reaching to about 15-45meV in monolayer TMDs [28][29][30] and 100meV in monolayer phosphorene on SiO2/Si substrate [31]. In addition, trions possess an extended population relaxation time up to tens of picoseconds [32,33]. Finally, trions have an impact on both transport and optical properties and can be easily detected and tuned experimentally [34].…”

Section: Excitons Trions Biexcitons and Interlayer Excitonsmentioning

confidence: 99%

Excitons in Two-Dimensional Materials

Zheng¹,

Zhang

2020

Advances in Condensed-Matter and Materials Physics - Rudimentary Research to Topical Technology

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Because of the reduced dielectric screening and enhanced Coulomb interactions, two-dimensional (2D) materials like phosphorene and transition metal dichalcogenides (TMDs) exhibit strong excitonic effects, resulting in fascinating many-particle phenomena covering both intralayer and interlayer excitons. Their intrinsic bandgaps and strong excitonic emissions allow the possibility to tune the inherent optical, electrical, and optoelectronic properties of 2D materials via a variety of external stimuli, making them potential candidates for novel optoelectronic applications. In this review, we summarize exciton physics and devices in 2D semiconductors and insulators, especially in phosphorene, TMDs, and their van der Waals heterostructures (vdWHs). In the first part, we discuss the remarkably versatile excitonic landscape, including bright and dark excitons, trions, biexcitons, and interlayer excitons. In the second part, we examine common control methods to tune excitonic effects via electrical, magnetic, optical, and mechanical means. In the next stage, we provide recent advances on the optoelectronic device applications, such as electroluminescent devices, photovoltaic solar cells, and photodetectors. We conclude with a brief discussion on their potential to exploit vdWHs towards unique exciton physics and devices.

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Valley trion dynamics in monolayer MoSe2

Cited by 60 publications

References 59 publications

Resonantly excited exciton dynamics in two-dimensional MoSe2 monolayers

Resonantly excited exciton dynamics in two-dimensional MoSe2 monolayers

Phonon-assisted oscillatory exciton dynamics in monolayer MoSe2

Excitons in Two-Dimensional Materials

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