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Tran TT, Lee Y, Roy S, Tran TU, Kim Y, Taniguchi T, Watanabe K, Milošević MV, Lim SC, Chaves A, Jang JI, Kim J. Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS 2 by Proximal Metal Plate and Negative Electric Bias. ACS NANO 2024; 18:220-228. [PMID: 38127273 DOI: 10.1021/acsnano.3c05667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
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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Affiliation(s)
- Trang Thu Tran
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yongjun Lee
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Shrawan Roy
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Thi Uyen Tran
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Youngbum Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Milorad V Milošević
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Instituto de Física, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78060-900, Brazil
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Andrey Chaves
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Departamento de Física, Universidade Federal do Ceará, Campus do Pici, C.P. 6030, 60455-900 Fortaleza, Ceará, Brazil
| | - Joon I Jang
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
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Sun X, Lu Z, Lu Y. Enhanced interactions of excitonic complexes in free-standing WS 2. NANOSCALE 2023. [PMID: 37937449 DOI: 10.1039/d3nr04594c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Excitonic complexes, bound states of electrons and holes, provide a promising platform in monolayer transition-metal dichalcogenide (TMDC) semiconductors for investigating diverse many-body interaction phenomena. The surrounding dielectric environment has been found to strongly influence the excitonic properties of the TMDC monolayers. While the impact of different dielectric surroundings on two-dimensional semiconductor materials and their strong correlations have been well studied, the effects on exciton formation and its properties resulting from a further reduction in dielectric screening remain elusive. In this study, we examined free-standing tungsten disulfide (WS2) monolayers, where the efficient generation of higher-order correlated excitonic complexes is readily observed. This phenomenon arises from the effective mutual interactions among excitons and internal carriers, attributed to the modulated exciton dynamics generated by the further reduced dielectric screening effect in the freestanding structure. The formation efficiency of excitonic complexes is enhanced and the multiple biexciton species (five particles such as charged biexcitons and acceptor/donor-bound biexcitons) are successfully induced under low excitation intensity and moderate temperature conditions. Our findings offer valuable insights into the influence of the dielectric environment on exciton interactions and enable a productive avenue for exploring fundamental many-body interactions, providing new possibilities for dielectric engineering of atomic thin semiconductors.
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Affiliation(s)
- Xueqian Sun
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, ACT, 2601, Australia
| | - Zhuoyuan Lu
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, ACT, 2601, Australia
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, ACT, 2601, Australia
- Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology, the Australian National University, Canberra, ACT, 2601, Australia.
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