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Zhang D, Ge C, Wang Y, Xia Y, Zhao H, Yao C, Chen Y, Ma C, Tong Q, Pan A, Wang X. Enhancing Layer-Engineered Interlayer Exciton Emission and Valley Polarization in van der Waals Heterostructures via Strain. ACS NANO 2024; 18:17672-17680. [PMID: 38920321 DOI: 10.1021/acsnano.4c02377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Layer-engineered interlayer excitons from heterostructures of transition-metal dichalcogenides (TMDCs) exhibit a rich variety of emissive states and intriguing valley spin-selection rules, the effective modulation of which is crucial for excitonic physics and related device applications. Strain or high pressure provides the possibility to tune the energy of the interlayer excitons; however, the reported emission intensity is substantially quenched, which greatly limits their practical application in optoelectronic devices. Here, via applying uniaxial strain based on polyvinyl alcohol (PVA) encapsulation technique, we report enhanced layer-engineered interlayer exciton emission intensity with largely modulated emission energy in WSe2/WS2 heterobilayer and heterotrilayer. Both momentum-direct and momentum-indirect interlayer excitons were observed, and their emission energies show an opposite shift tendency upon applied strain, which agrees with our DFT calculations. We further demonstrate that intralayer and interlayer exciton states with low phonon interactions can be modulated through the mechanical strain applied to the PVA substrate at low temperatures. Due to strain-induced breaking of the 3-fold rotational symmetry, we observe the enhanced valley polarization of interlayer excitons. Our study contributes to the understanding and modulation of the optical properties of interlayer excitons, which could be exploited for optoelectronic device applications.
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Affiliation(s)
- Danliang Zhang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Cuihuang Ge
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Youwen Wang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Yang Xia
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Haipeng Zhao
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Chengdong Yao
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Ying Chen
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Chao Ma
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Qingjun Tong
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Xiao Wang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
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2
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Xie X, Ding J, Wu B, Li S, Chen J, He J, Liu Z, Wang JT, Liu Y. Anomalous Phonon Behavior and Tunable Exciton Emissions: Insights into Pressure-Driven Dynamics in Silicon Phosphide. NANO LETTERS 2024; 24:8189-8197. [PMID: 38904278 DOI: 10.1021/acs.nanolett.4c02250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
IV-V two-dimensional materials have emerged as key contenders for polarization-sensitive and angle-resolved devices, given their inherent anisotropic physical properties. While these materials exhibit intriguing high-pressure quasi-particle behavior and phase transition, the evolution of quasi-particles and their interactions under external pressure remain elusive. Here, employing a diamond anvil cell and spectroscopic measurements coupled with first-principles calculations, we unveil rarely observed pressure-induced phonon-phonon coupling in layered SiP flakes. This coupling manifests as an anomalous phonon hardening behavior for the A1 mode within a broad wavenumber phonon softening region. Furthermore, we demonstrate the effective tuning of exciton emissions in SiP flakes under pressure, revealing a remarkable 63% enhancement in the degree of polarization (DOP) within the pressure range of 0-3.5 GPa. These findings contribute to our understanding of high-pressure phonon evolution in SiP materials and offer a strategic approach to manipulate the anisotropic performance of in-plane anisotropic 2D materials.
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Affiliation(s)
- Xing Xie
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Junnan Ding
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Biao Wu
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Shaofei Li
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Junying Chen
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Jun He
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
- The University of Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Jian-Tao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Yanping Liu
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- Shenzhen Research Institute of Central South University, Shenzhen 518000, People's Republic of China
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3
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Ge A, Ge X, Sun L, Lu X, Ma L, Zhao X, Yao B, Zhang X, Zhang T, Jing W, Zhou X, Shen X, Lu W. Unraveling the strain tuning mechanism of interlayer excitons in WSe 2/MoSe 2heterostructure. NANOTECHNOLOGY 2024; 35:175207. [PMID: 38266306 DOI: 10.1088/1361-6528/ad2232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/23/2024] [Indexed: 01/26/2024]
Abstract
Atomically thin transition metal dichalcogenides (TMDs) exhibit rich excitonic physics, due to reduced dielectric screening and strong Coulomb interactions. Especially, some attractive topics in modern condensed matter physics, such as correlated insulator, superconductivity, topological excitons bands, are recently reported in stacking two monolayer (ML) TMDs. Here, we clearly reveal the tuning mechanism of tensile strain on interlayer excitons (IEXs) and intralayer excitons (IAXs) in WSe2/MoSe2heterostructure (HS) at low temperature. We utilize the cryogenic tensile strain platform to stretch the HS, and measure by micro-photoluminescence (μ-PL). The PL peaks redshifts of IEXs and IAXs in WSe2/MoSe2HS under tensile strain are well observed. The first-principles calculations by using density functional theory reveals the PL peaks redshifts of IEXs and IAXs origin from bandgap shrinkage. The calculation results also show the Mo-4d states dominating conduction band minimum shifts of the ML MoSe2plays a dominant role in the redshifts of IEXs. This work provides new insights into understanding the tuning mechanism of tensile strain on IEXs and IAXs in two-dimensional (2D) HS, and paves a way to the development of flexible optoelectronic devices based on 2D materials.
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Affiliation(s)
- Anping Ge
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xun Ge
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
| | - Liaoxin Sun
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xinle Lu
- Key Laboratory of Polar Materials and Devices, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Lei Ma
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, People's Republic of China
| | - Xinchao Zhao
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Bimu Yao
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xin Zhang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- Department of Physics, Shanghai Normal University, Shanghai, 200234, People's Republic of China
| | - Tao Zhang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Wenji Jing
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xiaohao Zhou
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
| | - Xuechu Shen
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
| | - Wei Lu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
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Dai Y, Zhang Z, Zhao P, Cheng Y. Interlayer-coupling-engineerable flat bands in twisted MoSi 2N 4bilayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:165501. [PMID: 38211330 DOI: 10.1088/1361-648x/ad1d86] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
The two-dimensional layered semiconductor MoSi2N4, which has several advantages including high strength, excellent stability, high hole mobility, and high thermal conductivity, was recently successfully synthesized using chemical vapor deposition. Based on first-principles calculations, we investigate the effects of the twist angle and interlayer distance variation on the electronic properties of twisted bilayer MoSi2N4. The flat bands are absent for twisted bilayer MoSi2N4when the twist angleθis reduced to 3.89°. Taking twisted bilayer MoSi2N4withθof 5.09° as an example, we find that flat bands emerge as the interlayer distance decreases. As the interlayer distance can be effectively modulated by hydrostatic pressure, we propose hydrostatic pressure as a knob for tailoring the flat bands in twisted bilayer MoSi2N4. Our findings provide theoretical support for extending the applications of MoSi2N4in strong correlation physics and superconductivity.
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Affiliation(s)
- Yang Dai
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Zhineng Zhang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Puqin Zhao
- School of Physical and Mathematical Sciences, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Yingchun Cheng
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, People's Republic of China
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5
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Zhen J, Huang Q, Liu Y, Luo X, Zheng X, Guo S, Qiu J, Liu G. Strain-induced electronic structures and band-gap of few-layer AgInP 2S 6. NANOTECHNOLOGY 2023; 35:03LT01. [PMID: 37669636 DOI: 10.1088/1361-6528/acf6c5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/04/2023] [Indexed: 09/07/2023]
Abstract
The band gap and mechanical control ability of two-dimensional materials largely determine the application value of two-dimensional devices in optical and electronic properties, so the bandgap controllability of two-dimensional materials broadens the application range of multi-functional devices. In the layered van der Waals (vdW) material AgInP2S6, the band gap can be adjusted by the number of layers and flexible strain, and the few layers AgInP2S6have discrete band gap values, which are also relevant for optoelectronic applications. In the strain range of up to 2.7% applied, the band gap can be adjusted, and the film is relatively stable under strain. We further analyzed the physical mechanism of flexible strain band gap regulation and found that strain-regulation reduced the band gap and increased the chemical bond length. These studies open up new opportunities for the future development of vdW material photoelectric resonators represented by AgInP2S6, and have important reference value.
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Affiliation(s)
- Jiapeng Zhen
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
- Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
| | - Qiushi Huang
- Beijing Computational Science Research Center, Beijing 100093, People's Republic of China
| | - Ying Liu
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
- Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
| | - Xinyu Luo
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
- Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
| | - Xiande Zheng
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
- Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
| | - Silin Guo
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
- Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
| | - Jing Qiu
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
- Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
| | - Guanjun Liu
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
- Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha, Hunan 400713, People's Republic of China
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Xie X, Ding J, Wu B, Zheng H, Li S, Wang CT, He J, Liu Z, Wang JT, Liu Y. Pressure-Induced Dynamic Tuning of Interlayer Coupling in Twisted WSe 2/WSe 2 Homobilayers. NANO LETTERS 2023; 23:8833-8841. [PMID: 37726204 DOI: 10.1021/acs.nanolett.3c01640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Moiré superlattices induced by twisted van der Waals (vdW) heterostructures or homostructures have recently gained significant attention due to their potential to generate exotic strong-correlation electronic and phonon phenomena. However, the lack of dynamic tuning for interlayer coupling of moiré superlattices hinders a thorough understanding and development of the moiré correlation state. Here, we present a dynamic tuning method for twisted WSe2/WSe2 homobilayers using a diamond anvil cell (DAC). We demonstrate the powerful tuning of interlayer coupling and observe an enhanced response to pressure for interlayer breathing modes and the rapid descent of indirect excitons in twisted WSe2/WSe2 homobilayers. Our findings indicate that the introduction of a moiré superlattice for WSe2 bilayers gives rise to hybridized excitons, which lead to the different pressure-evolution exciton behaviors compared to natural WSe2 bilayers. Our results provide a novel understanding of moiré physics and offer an effective method to tune interlayer coupling of moiré superlattices.
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Affiliation(s)
- Xing Xie
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Junnan Ding
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Biao Wu
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Haihong Zheng
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Shaofei Li
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Chang-Tian Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jun He
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering, The University of Sydney, Camperdown, New South Wales 2006, Australia
- The University of Sydney Nano Institute, The University of Sydney, Camperdown, New South Wales 2006 Australia
| | - Jian-Tao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Yanping Liu
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- Shenzhen Research Institute of Central South University, Shenzhen 518000, People's Republic of China
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7
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Zhang Y, Liu H, Zhao Y, Lin J, Bai Y, Zhao J, Gao J. The effects of intercalated environmental gas molecules on carrier dynamics in WSe 2/WS 2 heterostructures. MATERIALS HORIZONS 2023. [PMID: 37074810 DOI: 10.1039/d3mh00420a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Effective tuning of carrier dynamics in two-dimensional (2D) materials is significant for multi-scene device applications. Using first-principles and ab initio nonadiabatic molecular dynamics calculations, the kinetics of O2, H2O, and N2 intercalation into 2D WSe2/WS2 van der Waals heterostructures and its effect on carrier dynamics have been comprehensively explored. It is found that the O2 molecule prefers to dissociate into atomic O atoms spontaneously after intercalation of WSe2/WS2 heterostructures, whereas H2O and N2 molecules remain intact. O2 intercalation significantly speeds up the electron separation process, while H2O intercalation largely speeds up the hole separation process. The lifetime of excited carriers can be prolonged by O2 or H2O or N2 intercalations. These intriguing phenomena can be attributed to the effect of interlayer coupling, and the underlying physical mechanism for tuning the carrier dynamics is fully discussed. Our results provide useful guidance for the experimental design of 2D heterostructures for optoelectronic applications in photocatalysts and solar energy cells.
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Affiliation(s)
- Yanxue Zhang
- State Key Laboratory of Structural Analysis, Optimization and CAE Software for Industrial Equipment (Dalian University of Technology), Ministry of Education, Dalian, 116024, China.
| | - Hongsheng Liu
- Key laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024, China
| | - Yanyan Zhao
- State Key Laboratory of Structural Analysis, Optimization and CAE Software for Industrial Equipment (Dalian University of Technology), Ministry of Education, Dalian, 116024, China.
| | - Jiaqi Lin
- The School of Bioengineering, Dalian University of Technology, Dalian, 116024, China.
| | - Yizhen Bai
- Key laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024, China
| | - Jijun Zhao
- State Key Laboratory of Structural Analysis, Optimization and CAE Software for Industrial Equipment (Dalian University of Technology), Ministry of Education, Dalian, 116024, China.
- Key laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024, China
| | - Junfeng Gao
- State Key Laboratory of Structural Analysis, Optimization and CAE Software for Industrial Equipment (Dalian University of Technology), Ministry of Education, Dalian, 116024, China.
- Key laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024, China
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8
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Park MU, Kim M, Kim SH, Lee C, Lee KS, Jeong J, Cho MH, Kim DY, Yoo KH. Funnel Devices Based on Asymmetrically Strained Transition Metal Dichalcogenides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209788. [PMID: 36750416 DOI: 10.1002/adma.202209788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/17/2023] [Indexed: 06/18/2023]
Abstract
The strain applied to transition metal dichalcogenides (TMDs) reduces their energy bandgap, and local strains result in a funnel-like band structure in which funneled excitons move toward the most strained region. Herein, a funnel device based on asymmetrically strained WS2 and MoS2 is reported. Asymmetric strains are induced by transferring the TMD flakes onto a fork-shaped SU-8 microstructure. Raman and photoluminescence spectra peaks are shifted according to the morphology of the SU-8 microstructure, indicating the application of asymmetric strains to the TMDs. To investigate whether funneled excitons can be converted to electrical currents, various devices are constructed by depositing symmetric and asymmetric electrodes onto the strained TMDs. The scanning photocurrent mapping images follow a fork-shaped pattern, indicating probable conversion of the funneled excitons into electrical currents. In the case of the funnel devices with asymmetric Au and Al electrodes, short-circuit current (ISC ) of WS2 is enhanced by the strains, whereas ISC of MoS2 is suppressed because the Schottky barrier lowers with increasing strain for the MoS2 . These results demonstrate that the funnel devices can be implemented using asymmetrically strained TMDs and the effect of strains on the Schottky barrier is dependent on the TMD used.
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Affiliation(s)
- Myung Uk Park
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
| | - Myeongjin Kim
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
| | - Sung Hyun Kim
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
| | - ChangJun Lee
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
| | - Kyo-Seok Lee
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
| | - Jaehun Jeong
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
| | - Mann-Ho Cho
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
| | - Dug Young Kim
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
| | - Kyung-Hwa Yoo
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul, 03722, Republic of Korea
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9
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Wang X, Niu G, Jiang J, Sui L, Zeng X, Liu X, Zhang Y, Wu G, Yuan K, Yang X. Anomalous Dynamics of Defect-Assisted Phonon Recycling in Few-Layer Mo 0.5W 0.5S 2. J Phys Chem Lett 2022; 13:10395-10403. [PMID: 36318176 DOI: 10.1021/acs.jpclett.2c02935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Alloying has emerged as a new strategy to tune the function of 2D transition metal dichalcogenides (TMDCs). However, the lack of research on the electrical and structural properties of these alloys limits their practical applications. Here, femtosecond transient absorption spectroscopy with pump pulse tunability is performed to elucidate the ultrafast carrier dynamics in the few-layer Mo0.5W0.5S2 prepared by the liquid phase exfoliation method. An anomalous rebleaching of the ground state is observed at high pump fluence by 3.1 eV excitation. We ascribe this rebleaching of the ground state to the mechanism that the carriers trapped in the defect are thermally excited back to the untrapped exciton state due to the phonon recycling, which hinders the dissipation of nonradiative energy, through comparative experiments and global analysis. Our findings demonstrate a novel energy transfer channel assisted by defect in few-layer TMDCs which is critical for their advanced applications.
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Affiliation(s)
- Xiaowei Wang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Guangming Niu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Jutao Jiang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Laizhi Sui
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xiangyu Zeng
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Xin Liu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Science College, Dalian Maritime University, Dalian 116026, China
| | - Yutong Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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