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Xu H, Wang J, Liu H, Chen S, Sun Z, Wang C, Han R, Wang Y, Wang Y, Wang Z, Huang S, Ma L, Liu D. Control of Hybrid Exciton Lifetime in MoSe 2/WS 2 Moiré Heterostructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2403127. [PMID: 38970212 DOI: 10.1002/advs.202403127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/12/2024] [Indexed: 07/08/2024]
Abstract
Hybrid excitons, characterized by their strong oscillation strength and long lifetimes, hold great potential as information carriers in semiconductors. They offer promising applications in exciton-based devices and circuits. MoSe2/WS2 heterostructures represent an ideal platform for studying hybrid excitons, but how to regulate the exciton lifetime has not yet been explored. In this study, layer hybridization is modulated by applying electric fields parallel or antiparallel to the dipole moment, enabling us to regulate the exciton lifetime from 1.36 to 4.60 ns. Furthermore, the time-resolved photoluminescence decay traces are measured at different excitation power. A hybrid exciton annihilation rate of 8.9 × 10-4 cm2 s-1 is obtained by fitting. This work reveals the effects of electric fields and excitation power on the lifetime of hybrid excitons in MoSe2/WS2 1.5° moiré heterostructures, which play important roles in high photoluminescence quantum yield optoelectronic devices based on transition-metal dichalcogenides heterostructures.
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Affiliation(s)
- Haowen Xu
- Institue for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing, 100083, China
| | - Jiangcai Wang
- State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China
| | - Huan Liu
- State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China
| | - Shihong Chen
- School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, China
| | - Zejun Sun
- State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China
| | - Chong Wang
- State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China
| | - Rui Han
- State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China
| | - Yong Wang
- Laboratory of Optical Detection and Imaging, School of Science, Qingdao University of Technology, Qingdao, 266033, China
| | - Yutang Wang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, 110819, China
| | - Zihao Wang
- School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, China
| | - Shuchun Huang
- State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China
| | - Lingwei Ma
- Institue for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing, 100083, China
| | - Dameng Liu
- State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China
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Zhu Y, Prezhdo OV, Long R, Fang WH. Twist Angle-Dependent Intervalley Charge Carrier Transfer and Recombination in Bilayer WS 2. J Am Chem Soc 2023; 145:22826-22835. [PMID: 37796526 DOI: 10.1021/jacs.3c09170] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
A twist angle at a van der Waals junction provides a handle to tune its optoelectronic properties for a variety of applications, and a comprehensive understanding of how the twist modulates electronic structure, interlayer coupling, and carrier dynamics is needed. We employ time-dependent density functional theory and nonadiabatic molecular dynamics to elucidate angle-dependent intervalley carrier transfer and recombination in bilayer WS2. Repulsion between S atoms in twisted configurations weakens interlayer coupling, increases the interlayer distance, and softens layer breathing modes. Twisting has a minor influence on K valleys while it lowers Γ valleys and raises Q valleys because their wave functions are delocalized between layers. Consequently, the reduced energy gaps between the K and Γ valleys accelerate the hole transfer in the twisted structures. Intervalley electron transfer proceeds nearly an order of magnitude faster than hole transfer. The more localized wave functions at K than Q values and larger bandgaps result in smaller nonadiabatic couplings for intervalley recombination, making it 3-4 times slower in twisted than high-symmetry structures. B2g breathing, E2g in-plane, and A1g out-of-plane modes are most active during intervalley carrier transfer and recombination. The faster intervalley transfer and extended carrier lifetimes in twisted junctions are favorable for optoelectronic device performance.
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Affiliation(s)
- Yonghao Zhu
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P.R. China
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P.R. China
| | - Wei-Hai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P.R. China
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Grubišić-Čabo A, Michiardi M, Sanders CE, Bianchi M, Curcio D, Phuyal D, Berntsen MH, Guo Q, Dendzik M. In Situ Exfoliation Method of Large-Area 2D Materials. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023:e2301243. [PMID: 37236159 PMCID: PMC10401183 DOI: 10.1002/advs.202301243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Indexed: 05/28/2023]
Abstract
2D materials provide a rich platform to study novel physical phenomena arising from quantum confinement of charge carriers. Many of these phenomena are discovered by surface sensitive techniques, such as photoemission spectroscopy, that work in ultra-high vacuum (UHV). Success in experimental studies of 2D materials, however, inherently relies on producing adsorbate-free, large-area, high-quality samples. The method that yields 2D materials of highest quality is mechanical exfoliation from bulk-grown samples. However, as this technique is traditionally performed in a dedicated environment, the transfer of samples into vacuum requires surface cleaning that might diminish the quality of the samples. In this article, a simple method for in situ exfoliation directly in UHV is reported, which yields large-area, single-layered films. Multiple metallic and semiconducting transition metal dichalcogenides are exfoliated in situ onto Au, Ag, and Ge. The exfoliated flakes are found to be of sub-millimeter size with excellent crystallinity and purity, as supported by angle-resolved photoemission spectroscopy, atomic force microscopy, and low-energy electron diffraction. The approach is well-suited for air-sensitive 2D materials, enabling the study of a new suite of electronic properties. In addition, the exfoliation of surface alloys and the possibility of controlling the substrate-2D material twist angle is demonstrated.
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Affiliation(s)
- Antonija Grubišić-Čabo
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, 9747 AG, The Netherlands
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, Stockholm, 114 19, Sweden
| | - Matteo Michiardi
- Quantum Matter Institute, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - Charlotte E Sanders
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus, Didcot, 0X11 0QX, UK
| | - Marco Bianchi
- School of Physics and Astronomy, Aarhus University, Aarhus, 8000 C, Denmark
| | - Davide Curcio
- School of Physics and Astronomy, Aarhus University, Aarhus, 8000 C, Denmark
| | - Dibya Phuyal
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, Stockholm, 114 19, Sweden
| | - Magnus H Berntsen
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, Stockholm, 114 19, Sweden
| | - Qinda Guo
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, Stockholm, 114 19, Sweden
| | - Maciej Dendzik
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, Stockholm, 114 19, Sweden
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