1
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Xu Y, Wang Y, Yu S, Sun D, Dai Y, Huang B, Wei W. High-Temperature Excitonic Condensation in 2D Lattice. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2404436. [PMID: 39239846 DOI: 10.1002/advs.202404436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 07/24/2024] [Indexed: 09/07/2024]
Abstract
Exploration of high-temperature bosonic condensation is of significant importance for the fundamental many-body physics and applications in nanodevices, which, however, remains a huge challenge. Here, in combination of many-body perturbation theory and first-principles calculations, a new-type spatially indirect exciton can be optically generated in two-dimensional (2D) Bi2S2Te because of its unique structure feature. In particular, the spin-singlet spatially indirect excitons in Bi2S2Te monolayer are dipole/parity allowed and reveal befitting characteristics for excitonic condensation, such as small effective mass and satisfied dilute limitation. Based on the layered Bi2S2Te, the possibility of the high-temperature excitonic Bose-Einstein condensation (BEC) and superfluid state in two dimensions, which goes beyond the current paradigms in both experiment and theory, are proved. It should be highlighted that record-high phase transition temperatures of 289.7 and 72.4 K can be theoretically predicted for the excitonic BEC and superfluidity in the atomic thin Bi2S2Te, respectively. It therefore can be confirmed that Bi2S2Te featuring bound bosonic states is a fascinating 2D platform for exploring the high-temperature excitonic condensation and applications in such as quantum computing and dissipationless nanodevices.
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Affiliation(s)
- Yushuo Xu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Yuanyuan Wang
- Science, Mathematics and Technology Cluster, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Shiqiang Yu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Dongyue Sun
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Wei Wei
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
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2
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Joe AY, Mier Valdivia AM, Jauregui LA, Pistunova K, Ding D, Zhou Y, Scuri G, De Greve K, Sushko A, Kim B, Taniguchi T, Watanabe K, Hone JC, Lukin MD, Park H, Kim P. Controlled interlayer exciton ionization in an electrostatic trap in atomically thin heterostructures. Nat Commun 2024; 15:6743. [PMID: 39112505 PMCID: PMC11306233 DOI: 10.1038/s41467-024-51128-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Accepted: 07/30/2024] [Indexed: 08/10/2024] Open
Abstract
Atomically thin semiconductor heterostructures provide a two-dimensional (2D) device platform for creating high densities of cold, controllable excitons. Interlayer excitons (IEs), bound electrons and holes localized to separate 2D quantum well layers, have permanent out-of-plane dipole moments and long lifetimes, allowing their spatial distribution to be tuned on demand. Here, we employ electrostatic gates to trap IEs and control their density. By electrically modulating the IE Stark shift, electron-hole pair concentrations above 2 × 1012 cm-2 can be achieved. At this high IE density, we observe an exponentially increasing linewidth broadening indicative of an IE ionization transition, independent of the trap depth. This runaway threshold remains constant at low temperatures, but increases above 20 K, consistent with the quantum dissociation of a degenerate IE gas. Our demonstration of the IE ionization in a tunable electrostatic trap represents an important step towards the realization of dipolar exciton condensates in solid-state optoelectronic devices.
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Affiliation(s)
- Andrew Y Joe
- Department of Physics, Harvard University, Cambridge, MA, USA
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | - Andrés M Mier Valdivia
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Luis A Jauregui
- Department of Physics, University of California, Irvine, CA, USA
| | | | - Dapeng Ding
- Department of Physics, Harvard University, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - You Zhou
- Department of Physics, Harvard University, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, MD, USA
| | - Giovanni Scuri
- Department of Physics, Harvard University, Cambridge, MA, USA
- E. L. Ginzton Laboratory, Stanford University, Stanford, CA, USA
| | - Kristiaan De Greve
- Department of Physics, Harvard University, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Andrey Sushko
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Bumho Kim
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
| | - James C Hone
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Hongkun Park
- Department of Physics, Harvard University, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, MA, USA.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
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3
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Ju Q, Cai Q, Jian C, Hong W, Sun F, Wang B, Liu W. Infrared Interlayer Excitons in Twist-Free MoTe 2/MoS 2 Heterobilayers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2404371. [PMID: 39007276 DOI: 10.1002/adma.202404371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/13/2024] [Indexed: 07/16/2024]
Abstract
Excitonic devices based on interlayer excitons in van der Waals heterobilayers are a promising platform for advancing photoelectric interconnection telecommunications. However, the absence of exciton emission in the crucial telecom C-band has constrained their practical applications. Here, this limitation is addressed by reporting exciton emission at 0.8 eV (1550 nm) in a chemically vapor-deposited, strictly aligned MoTe2/MoS2 heterobilayer, resulting from the direct bandgap transitions of interlayer excitons as identified by momentum-space imaging of their electrons and holes. The decay mechanisms dominated by direct radiative recombination ensure constant emission quantum yields, a basic demand for efficient excitonic devices. The atomically sharp interface enables the resolution of two narrowly-splitter transitions induced by spin-orbit coupling, further distinguished through the distinct Landé g-factors as the fingerprint of spin configurations. By electrical control, the double transitions coupling into opposite circularly-polarized photon modes, preserve or reverse the helicities of the incident light with a degree of polarization up to 90%. The Stark effect tuning extends the emission energy range by over 150 meV (270 nm), covering the telecom C-band. The findings provide a material platform for studying the excitonic complexes and significantly boost the application prospects of excitonic devices in silicon photonics and all-optical telecommunications.
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Affiliation(s)
- Qiankun Ju
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Materials and Techniques toward Hydrogen Energy, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qian Cai
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Materials and Techniques toward Hydrogen Energy, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China
| | - Chuanyong Jian
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Materials and Techniques toward Hydrogen Energy, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China
| | - Wenting Hong
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Materials and Techniques toward Hydrogen Energy, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China
| | - Fapeng Sun
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Materials and Techniques toward Hydrogen Energy, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Bicheng Wang
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Materials and Techniques toward Hydrogen Energy, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China
| | - Wei Liu
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Materials and Techniques toward Hydrogen Energy, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, Fujian, 350108, P. R. China
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4
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Zhang L, Gu L, Ni R, Xie M, Park S, Jang H, Ma R, Taniguchi T, Watanabe K, Zhou Y. Electrical Control and Transport of Tightly Bound Interlayer Excitons in a MoSe_{2}/hBN/MoSe_{2} Heterostructure. PHYSICAL REVIEW LETTERS 2024; 132:216903. [PMID: 38856288 DOI: 10.1103/physrevlett.132.216903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/11/2024] [Accepted: 04/15/2024] [Indexed: 06/11/2024]
Abstract
Controlling interlayer excitons in Van der Waals heterostructures holds promise for exploring Bose-Einstein condensates and developing novel optoelectronic applications, such as excitonic integrated circuits. Despite intensive studies, several key fundamental properties of interlayer excitons, such as their binding energies and interactions with charges, remain not well understood. Here we report the formation of momentum-direct interlayer excitons in a high-quality MoSe_{2}/hBN/MoSe_{2} heterostructure under an electric field, characterized by bright photoluminescence (PL) emission with high quantum yield and a narrow linewidth of less than 4 meV. These interlayer excitons show electrically tunable emission energy spanning ∼180 meV through the Stark effect, and exhibit a sizable binding energy of ∼81 meV in the intrinsic regime, along with trion binding energies of a few millielectronvolts. Remarkably, we demonstrate the long-range transport of interlayer excitons with a characteristic diffusion length exceeding 10 μm, which can be attributed, in part, to their dipolar repulsive interactions. Spatially and polarization-resolved spectroscopic studies reveal rich exciton physics in the system, such as valley polarization, local trapping, and the possible existence of dark interlayer excitons. The formation and transport of tightly bound interlayer excitons with narrow linewidth, coupled with the ability to electrically manipulate their properties, open exciting new avenues for exploring quantum many-body physics, including excitonic condensate and superfluidity, and for developing novel optoelectronic devices, such as exciton and photon routers.
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Affiliation(s)
- Lifu Zhang
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Liuxin Gu
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Ruihao Ni
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Ming Xie
- Condensed Matter Theory Center, University of Maryland, College Park, Maryland 20742, USA
| | - Suji Park
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Houk Jang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Rundong Ma
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Takashi Taniguchi
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - You Zhou
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
- Maryland Quantum Materials Center, College Park, Maryland 20742, USA
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5
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Singh J, Astarini NA, Tsai M, Venkatesan M, Kuo C, Yang C, Yen H. Growth of Wafer-Scale Single-Crystal 2D Semiconducting Transition Metal Dichalcogenide Monolayers. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307839. [PMID: 38164110 PMCID: PMC10953574 DOI: 10.1002/advs.202307839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/28/2023] [Indexed: 01/03/2024]
Abstract
Due to extraordinary electronic and optoelectronic properties, large-scale single-crystal two-dimensional (2D) semiconducting transition metal dichalcogenide (TMD) monolayers have gained significant interest in the development of profit-making cutting-edge nano and atomic-scale devices. To explore the remarkable properties of single-crystal 2D monolayers, many strategies are proposed to achieve ultra-thin functional devices. Despite substantial attempts, the controllable growth of high-quality single-crystal 2D monolayer still needs to be improved. The quality of the 2D monolayer strongly depends on the underlying substrates primarily responsible for the formation of grain boundaries during the growth process. To restrain the grain boundaries, the epitaxial growth process plays a crucial role and becomes ideal if an appropriate single crystal substrate is selected. Therefore, this perspective focuses on the latest advances in the growth of large-scale single-crystal 2D TMD monolayers in the light of enhancing their industrial applicability. In the end, recent progress and challenges of 2D TMD materials for various potential applications are highlighted.
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Affiliation(s)
- Jitendra Singh
- Department of Materials Science and EngineeringNational Taiwan University of Science and TechnologyTaipei City106335Taiwan
- Department of PhysicsUdit Narayan Post Graduate College PadraunaKushinagarUttar Pradesh274304India
| | - Nadiya Ayu Astarini
- Department of Materials Science and EngineeringNational Taiwan University of Science and TechnologyTaipei City106335Taiwan
| | - Meng‐Lin Tsai
- Department of Materials Science and EngineeringNational Taiwan University of Science and TechnologyTaipei City106335Taiwan
| | - Manikandan Venkatesan
- Department of Molecular Science and EngineeringInstitute of Organic and Polymeric MaterialsNational Taipei University of TechnologyTaipei City106344Taiwan
| | - Chi‐Ching Kuo
- Department of Molecular Science and EngineeringInstitute of Organic and Polymeric MaterialsNational Taipei University of TechnologyTaipei City106344Taiwan
| | - Chan‐Shan Yang
- Institute and Undergraduate Program of Electro‐Optical EngineeringNational Taiwan Normal UniversityTaipei City11677Taiwan
| | - Hung‐Wei Yen
- Department of Materials Science and EngineeringNational Taiwan UniversityTaipei City106319Taiwan
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6
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Qian W, Qi P, Dai Y, Shi B, Tao G, Liu H, Zhang X, Xiang D, Fang Z, Liu W. Strongly Localized Moiré Exciton in Twisted Homobilayers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305200. [PMID: 37649150 DOI: 10.1002/smll.202305200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/14/2023] [Indexed: 09/01/2023]
Abstract
Artificially molding exciton flux is the cornerstone for developing promising excitonic devices. In the emerging hetero/homobilayers, the spatial separated charges prolong exciton lifetimes and create out-plane dipoles, facilitating electrically control exciton flux on a large scale, and the nanoscale periodic moiré potentials arising from twist-angle or/and lattice mismatch can substantially alter exciton dynamics, which are mainly proved in the heterostructures. However, the spatially indirect excitons dynamics in homobilayers without lattice mismatch remain elusive. Here the nonequilibrium dynamics of indirect exciton in homobilayers are systematically investigated. The homobilayers with slightly twist-angle can induce a deep moiré potential (>50 meV) in the energy landscape of indirect excitons, resulting in a strongly localized moiré excitons insulating the transport dynamics from phonons and disorder. These findings provide insights into the exciton dynamics and many-body physics in moiré superlattices modulated energy landscape, with implications for designing excitonic devices operating at room temperature.
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Affiliation(s)
- Wenqi Qian
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Pengfei Qi
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Yuchen Dai
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing, 100871, China
| | - Beibei Shi
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing, 100871, China
| | - Guangyi Tao
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing, 100871, China
| | - Haiyi Liu
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Xubin Zhang
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Dong Xiang
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
| | - Zheyu Fang
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing, 100871, China
| | - Weiwei Liu
- Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China
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7
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Obaidulla SM, Supina A, Kamal S, Khan Y, Kralj M. van der Waals 2D transition metal dichalcogenide/organic hybridized heterostructures: recent breakthroughs and emerging prospects of the device. NANOSCALE HORIZONS 2023; 9:44-92. [PMID: 37902087 DOI: 10.1039/d3nh00310h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
The near-atomic thickness and organic molecular systems, including organic semiconductors and polymer-enabled hybrid heterostructures, of two-dimensional transition metal dichalcogenides (2D-TMDs) can modulate their optoelectronic and transport properties outstandingly. In this review, the current understanding and mechanism of the most recent and significant breakthrough of novel interlayer exciton emission and its modulation by harnessing the band energy alignment between TMDs and organic semiconductors in a TMD/organic (TMDO) hybrid heterostructure are demonstrated. The review encompasses up-to-date device demonstrations, including field-effect transistors, detectors, phototransistors, and photo-switchable superlattices. An exploration of distinct traits in 2D-TMDs and organic semiconductors delves into the applications of TMDO hybrid heterostructures. This review provides insights into the synthesis of 2D-TMDs and organic layers, covering fabrication techniques and challenges. Band bending and charge transfer via band energy alignment are explored from both structural and molecular orbital perspectives. The progress in emission modulation, including charge transfer, energy transfer, doping, defect healing, and phase engineering, is presented. The recent advancements in 2D-TMDO-based optoelectronic synaptic devices, including various 2D-TMDs and organic materials for neuromorphic applications are discussed. The section assesses their compatibility for synaptic devices, revisits the operating principles, and highlights the recent device demonstrations. Existing challenges and potential solutions are discussed. Finally, the review concludes by outlining the current challenges that span from synthesis intricacies to device applications, and by offering an outlook on the evolving field of emerging TMDO heterostructures.
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Affiliation(s)
- Sk Md Obaidulla
- Center of Excellence for Advanced Materials and Sensing Devices, Institute of Physics, Bijenička Cesta 46, HR-10000 Zagreb, Croatia.
- Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, Sector III, Block JD, Salt Lake, Kolkata 700106, India
| | - Antonio Supina
- Center of Excellence for Advanced Materials and Sensing Devices, Institute of Physics, Bijenička Cesta 46, HR-10000 Zagreb, Croatia.
- Chair of Physics, Montanuniversität Leoben, Franz Josef Strasse 18, 8700 Leoben, Austria
| | - Sherif Kamal
- Center of Excellence for Advanced Materials and Sensing Devices, Institute of Physics, Bijenička Cesta 46, HR-10000 Zagreb, Croatia.
| | - Yahya Khan
- Department of Physics, Karakoram International university (KIU), Gilgit 15100, Pakistan
| | - Marko Kralj
- Center of Excellence for Advanced Materials and Sensing Devices, Institute of Physics, Bijenička Cesta 46, HR-10000 Zagreb, Croatia.
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8
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Lee H, Kim YB, Ryu JW, Kim S, Bae J, Koo Y, Jang D, Park KD. Recent progress of exciton transport in two-dimensional semiconductors. NANO CONVERGENCE 2023; 10:57. [PMID: 38102309 PMCID: PMC10724105 DOI: 10.1186/s40580-023-00404-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023]
Abstract
Spatial manipulation of excitonic quasiparticles, such as neutral excitons, charged excitons, and interlayer excitons, in two-dimensional semiconductors offers unique capabilities for a broad range of optoelectronic applications, encompassing photovoltaics, exciton-integrated circuits, and quantum light-emitting systems. Nonetheless, their practical implementation is significantly restricted by the absence of electrical controllability for neutral excitons, short lifetime of charged excitons, and low exciton funneling efficiency at room temperature, which remain a challenge in exciton transport. In this comprehensive review, we present the latest advancements in controlling exciton currents by harnessing the advanced techniques and the unique properties of various excitonic quasiparticles. We primarily focus on four distinct control parameters inducing the exciton current: electric fields, strain gradients, surface plasmon polaritons, and photonic cavities. For each approach, the underlying principles are introduced in conjunction with its progression through recent studies, gradually expanding their accessibility, efficiency, and functionality. Finally, we outline the prevailing challenges to fully harness the potential of excitonic quasiparticles and implement practical exciton-based optoelectronic devices.
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Affiliation(s)
- Hyeongwoo Lee
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Yong Bin Kim
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jae Won Ryu
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Sujeong Kim
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jinhyuk Bae
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Yeonjeong Koo
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Donghoon Jang
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Kyoung-Duck Park
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
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9
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Li Z, Florian M, Datta K, Jiang Z, Borsch M, Wen Q, Kira M, Deotare PB. Enhanced Exciton Drift Transport through Suppressed Diffusion in One-Dimensional Guides. ACS NANO 2023; 17:22410-22417. [PMID: 37874891 DOI: 10.1021/acsnano.3c04870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Drift-diffusion dynamics is investigated in a one-dimensional (1D) exciton guide at room temperature. Spatial engineering of the exciton energy in a WSe2 monolayer is achieved using local strain to confine and direct exciton transport. An unexpected and massive deviation from the Einstein relation is observed and correlated to exciton capture by defects. We find that the capture reduces exciton temperature and diffusion so much that drift transport visibility improves to 38% as excitons traverse asymmetrically over regions with occupied defect states. Based on measurements over multiple potential gradients, we estimate the exciton mobility to be 169 ± 39 cm2/(eV s) at room temperature. Experiments at elevated exciton densities reveal that the exciton drift velocity monotonically increases with exciton density, unlike exciton mobility, due to contributions from nonequilibrium many-body effects.
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Affiliation(s)
- Zidong Li
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Matthias Florian
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kanak Datta
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zhaohan Jiang
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Markus Borsch
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Qiannan Wen
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Mack Kira
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Parag B Deotare
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
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10
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Kim JH, Lee J, Seo C, Han GH, Cho BW, Kim J, Lee YH, Lee HS. Polymer-Waveguide-Integrated 2D Semiconductor Heterostructures for Optical Communications. NANO LETTERS 2023. [PMID: 37988451 DOI: 10.1021/acs.nanolett.3c03317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
The demand for high-speed and low-loss interconnects in modern computer architectures is difficult to satisfy by using traditional Si-based electronics. Although optical interconnects offer a promising solution owing to their high bandwidth, low energy dissipation, and high-speed processing, integrating elements such as a light source, detector, and modulator, comprising different materials with optical waveguides, presents many challenges in an integrated platform. Two-dimensional (2D) van der Waals (vdW) semiconductors have attracted considerable attention in vertically stackable optoelectronics and advanced flexible photonics. In this study, optoelectronic components for exciton-based photonic circuits are demonstrated by integrating lithographically patterned poly(methyl methacrylate) (PMMA) waveguides on 2D vdW devices. The excitonic signals generated from the 2D materials by using laser excitation were transmitted through patterned PMMA waveguides. By introducing an external electric field and combining vdW heterostructures, an excitonic switch, phototransistor, and guided-light photovoltaic device on SiO2/Si substrates were demonstrated.
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Affiliation(s)
- Jung Ho Kim
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jubok Lee
- Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Changwon Seo
- Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Physics, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Gang Hee Han
- Department of Physics, Incheon National University, Incheon 22012, Republic of Korea
| | - Byeong Wook Cho
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyun Seok Lee
- Department of Physics, Research Institute for Nanoscale Science and Technology, Chungbuk National University, Cheongju 28644, Republic of Korea
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11
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Zhu G, Zhang L, Li W, Shi X, Zou Z, Guo Q, Li X, Xu W, Jie J, Wang T, Du W, Xiong Q. Room-temperature high-speed electrical modulation of excitonic distribution in a monolayer semiconductor. Nat Commun 2023; 14:6701. [PMID: 37872139 PMCID: PMC10593816 DOI: 10.1038/s41467-023-42568-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 10/16/2023] [Indexed: 10/25/2023] Open
Abstract
Excitons in monolayer semiconductors, benefitting from their large binding energies, hold great potential towards excitonic circuits bridging nano-electronics and photonics. However, achieving room-temperature ultrafast on-chip electrical modulation of excitonic distribution and flow in monolayer semiconductors is nontrivial. Here, utilizing lateral bias, we report high-speed electrical modulation of the excitonic distribution in a monolayer semiconductor junction at room temperature. The alternating charge trapping/detrapping at the two monolayer/electrode interfaces induces a non-uniform carrier distribution, leading to controlled in-plane spatial variations of excitonic populations, and mimicking a bias-driven excitonic flow. This modulation increases with the bias amplitude and eventually saturates, relating to the energetic distribution of trap density of states. The switching time of the modulation is down to 5 ns, enabling high-speed excitonic devices. Our findings reveal the trap-assisted exciton engineering in monolayer semiconductors and offer great opportunities for future two-dimensional excitonic devices and circuits.
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Affiliation(s)
- Guangpeng Zhu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Lan Zhang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Wenfei Li
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Xiuqi Shi
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Zhen Zou
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Qianqian Guo
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Xiang Li
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Weigao Xu
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, PR China
| | - Jiansheng Jie
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Tao Wang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China.
| | - Wei Du
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China.
| | - Qihua Xiong
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, PR China
- Frontier Science Center for Quantum Information, Beijing, 100084, PR China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, PR China
- Collaborative Innovation Center of Quantum Matter, Beijing, PR China
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12
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Lamsaadi H, Beret D, Paradisanos I, Renucci P, Lagarde D, Marie X, Urbaszek B, Gan Z, George A, Watanabe K, Taniguchi T, Turchanin A, Lombez L, Combe N, Paillard V, Poumirol JM. Kapitza-resistance-like exciton dynamics in atomically flat MoSe 2-WSe 2 lateral heterojunction. Nat Commun 2023; 14:5881. [PMID: 37735478 PMCID: PMC10514293 DOI: 10.1038/s41467-023-41538-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/08/2023] [Indexed: 09/23/2023] Open
Abstract
Being able to control the neutral excitonic flux is a mandatory step for the development of future room-temperature two-dimensional excitonic devices. Semiconducting Monolayer Transition Metal Dichalcogenides (TMD-ML) with extremely robust and mobile excitons are highly attractive in this regard. However, generating an efficient and controlled exciton transport over long distances is a very challenging task. Here we demonstrate that an atomically sharp TMD-ML lateral heterostructure (MoSe2-WSe2) transforms the isotropic exciton diffusion into a unidirectional excitonic flow through the junction. Using tip-enhanced photoluminescence spectroscopy (TEPL) and a modified exciton transfer model, we show a discontinuity of the exciton density distribution on each side of the interface. We introduce the concept of exciton Kapitza resistance, by analogy with the interfacial thermal resistance referred to as Kapitza resistance. By comparing different heterostructures with or without top hexagonal boron nitride (hBN) layer, we deduce that the transport properties can be controlled, over distances far greater than the junction width, by the exciton density through near-field engineering and/or laser power density. This work provides a new approach for controlling the neutral exciton flow, which is key toward the conception of excitonic devices.
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Affiliation(s)
| | - Dorian Beret
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Ioannis Paradisanos
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion, 70013, Greece
| | - Pierre Renucci
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Delphine Lagarde
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Bernhard Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Ziyang Gan
- Friedrich Schiller University Jena, Institute of Physical Chemistry, 07743, Jena, Germany
| | - Antony George
- Friedrich Schiller University Jena, Institute of Physical Chemistry, 07743, Jena, Germany
- Abbe Centre of Photonics, 07745, Jena, Germany
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Andrey Turchanin
- Friedrich Schiller University Jena, Institute of Physical Chemistry, 07743, Jena, Germany
- Abbe Centre of Photonics, 07745, Jena, Germany
| | - Laurent Lombez
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France.
| | - Nicolas Combe
- CEMES-CNRS, Université de Toulouse, Toulouse, France
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13
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Hart SM, Gorman J, Bathe M, Schlau-Cohen GS. Engineering Exciton Dynamics with Synthetic DNA Scaffolds. Acc Chem Res 2023; 56:2051-2061. [PMID: 37345736 DOI: 10.1021/acs.accounts.3c00086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
Excitons are the molecular-scale currency of electronic energy. Control over excitons enables energy to be directed and harnessed for light harvesting, electronics, and sensing. Excitonic circuits achieve such control by arranging electronically active molecules to prescribe desired spatiotemporal dynamics. Photosynthetic solar energy conversion is a canonical example of the power of excitonic circuits, where chromophores are positioned in a protein scaffold to perform efficient light capture, energy transport, and charge separation. Synthetic systems that aim to emulate this functionality include self-assembled aggregates, molecular crystals, and chromophore-modified proteins. While the potential of this approach is clear, these systems lack the structural precision to control excitons or even test the limits of their power. In recent years, DNA origami has emerged as a designer material that exploits biological building blocks to construct nanoscale architectures. The structural precision afforded by DNA origami has enabled the pursuit of naturally inspired organizational principles in a highly precise and scalable manner. In this Account, we describe recent developments in DNA-based platforms that spatially organize chromophores to construct tunable excitonic systems. The high fidelity of DNA base pairing enables the formation of programmable nanoscale architectures, and sequence-specific placement allows for the precise positioning of chromophores within the DNA structure. The integration of a wide range of chromophores across the visible spectrum introduces spectral tunability. These excitonic DNA-chromophore assemblies not only serve as model systems for light harvesting, solar conversion, and sensing but also lay the groundwork for the integration of coupled chromophores into larger-scale nucleic acid architectures.We have used this approach to generate DNA-chromophore assemblies of strongly coupled delocalized excited states through both sequence-specific self-assembly and the covalent attachment of chromophores. These strategies have been leveraged to independently control excitonic coupling and system-bath interaction, which together control energy transfer. We then extended this framework to identify how scaffold configurations can steer the formation of symmetry-breaking charge transfer states, paving the way toward the design of dual light-harvesting and charge separation DNA machinery. In an orthogonal application, we used the programmability of DNA chromophore assemblies to change the optical emission properties of strongly coupled dimers, generating a series of fluorophore-modified constructs with separable emission properties for fluorescence assays. Upcoming advances in the chemical modification of nucleotides, design of large-scale DNA origami, and predictive computational methods will aid in constructing excitonic assemblies for optical and computing applications. Collectively, the development of DNA-chromophore assemblies as a platform for excitonic circuitry offers a pathway to identifying and applying design principles for light harvesting and molecular electronics.
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Affiliation(s)
- Stephanie M Hart
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jeffrey Gorman
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Mark Bathe
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Gabriela S Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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14
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Lee S, Choi WH, Cho H, Lee SH, Choi W, Joo J, Lee D, Gong SH. Electric-Field-Driven Trion Drift and Funneling in MoSe 2 Monolayer. NANO LETTERS 2023; 23:4282-4289. [PMID: 37167152 PMCID: PMC10215787 DOI: 10.1021/acs.nanolett.3c00460] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 05/08/2023] [Indexed: 05/13/2023]
Abstract
Excitons, electron-hole pairs in semiconductors, can be utilized as information carriers with a spin or valley degree of freedom. However, manipulation of excitons' motion is challenging because of their charge-neutral characteristic and short recombination lifetimes. Here we demonstrate electric-field-driven drift and funneling of charged excitons (i.e., trions) toward the center of a MoSe2 monolayer. Using a simple bottom-gate device, we control the electric fields in the vicinity of the suspended monolayer, which increases the trion density and pulls down the layer. We observe that locally excited trions are subjected to electric force and, consequently, drift toward the center of the stretched layer. The exerting electric force on the trion is estimated to be 102-104 times stronger than the strain-induced force in the stretched monolayer, leading to the successful observation of trion drift under continuous-wave excitation. Our findings provide a new route for manipulating trions and achieving new types of optoelectronic devices.
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Affiliation(s)
- Seong
Won Lee
- Department
of Physics, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
- KU
Photonics Center, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Woo Hun Choi
- Department
of Physics, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
- KU
Photonics Center, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - HyunHee Cho
- Department
of Physics, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Sang-hun Lee
- Department
of Physics, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Wookyoung Choi
- Department
of Physics, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jinsoo Joo
- Department
of Physics, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Donghun Lee
- Department
of Physics, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Su-Hyun Gong
- Department
of Physics, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
- KU
Photonics Center, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
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15
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Abstract
In superlattices of twisted semiconductor monolayers, tunable moiré potentials emerge, trapping excitons into periodic arrays. In particular, spatially separated interlayer excitons are subject to a deep potential landscape and they exhibit a permanent dipole providing a unique opportunity to study interacting bosonic lattices. Recent experiments have demonstrated density-dependent transport properties of moiré excitons, which could play a key role for technological applications. However, the intriguing interplay between exciton-exciton interactions and moiré trapping has not been well understood yet. In this work, we develop a microscopic theory of interacting excitons in external potentials allowing us to tackle this highly challenging problem. We find that interactions between moiré excitons lead to a delocalization at intermediate densities, and we show how this transition can be tuned via twist angle and temperature. The delocalization is accompanied by a modification of optical moiré resonances, which gradually merge into a single free exciton peak.
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Affiliation(s)
- Samuel Brem
- Department of Physics, Philipps University, 35037 Marburg, Germany
| | - Ermin Malic
- Department of Physics, Philipps University, 35037 Marburg, Germany
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16
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Lee H, Koo Y, Kumar S, Jeong Y, Heo DG, Choi SH, Joo H, Kang M, Siddique RH, Kim KK, Lee HS, An S, Choo H, Park KD. All-optical control of high-purity trions in nanoscale waveguide. Nat Commun 2023; 14:1891. [PMID: 37045823 PMCID: PMC10097695 DOI: 10.1038/s41467-023-37481-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/20/2023] [Indexed: 04/14/2023] Open
Abstract
The generation of high-purity localized trions, dynamic exciton-trion interconversion, and their spatial modulation in two-dimensional (2D) semiconductors are building blocks for the realization of trion-based optoelectronic devices. Here, we present a method for the all-optical control of the exciton-to-trion conversion process and its spatial distributions in a MoS2 monolayer. We induce a nanoscale strain gradient in a 2D crystal transferred on a lateral metal-insulator-metal (MIM) waveguide and exploit propagating surface plasmon polaritons (SPPs) to localize hot electrons. These significantly increase the electrons and efficiently funnel excitons in the lateral MIM waveguide, facilitating complete exciton-to-trion conversion even at ambient conditions. Additionally, we modulate the SPP mode using adaptive wavefront shaping, enabling all-optical control of the exciton-to-trion conversion rate and trion distribution in a reversible manner. Our work provides a platform for harnessing excitonic quasiparticles efficiently in the form of trions at ambient conditions, enabling high-efficiency photoconversion.
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Affiliation(s)
- Hyeongwoo Lee
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Yeonjeong Koo
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Shailabh Kumar
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA, 91125, USA
- Meta Vision Lab, Samsung Advanced Institute of Technology (SAIT), Pasadena, CA, 91101, USA
| | - Yunjo Jeong
- Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeonbuk, 55324, Republic of Korea
| | - Dong Gwon Heo
- Department of Physics, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Soo Ho Choi
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
| | - Huitae Joo
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Mingu Kang
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Radwanul Hasan Siddique
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA, 91125, USA
- Meta Vision Lab, Samsung Advanced Institute of Technology (SAIT), Pasadena, CA, 91101, USA
| | - Ki Kang Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Hong Seok Lee
- Department of Physics, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju, 54896, Republic of Korea.
| | - Sangmin An
- Department of Physics, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Hyuck Choo
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA, 91125, USA.
- Advanced Sensor Lab, Device Research Center, Samsung Advanced Institute of Technology (SAIT), Suwon, 16678, Republic of Korea.
| | - Kyoung-Duck Park
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
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17
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Xu Y, Wang Y, Wang S, Yu S, Huang B, Dai Y, Wei W. Spontaneous Valley Polarization Caused by Crystalline Symmetry Breaking in Nonmagnetic LaOMX 2 Monolayers. NANO LETTERS 2022; 22:9147-9153. [PMID: 36367360 DOI: 10.1021/acs.nanolett.2c03791] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In order to achieve valley polarization, breaking the time-reversal symmetry in two-dimensional hexagonal lattices with inversion asymmetry is the heart of current valleytronic research, which, however, has caused studies to stagnate due to the inevitable drawbacks. In this work, we go beyond the conventional paradigm and demonstrate the novel valley physics caused by lowering the crystalline symmetry instead of breaking the time-reversal symmetry. In particular, we translate our concept into concrete nonmagnetic LaOMX2 monolayers with a tetragonal lattice, confirming that a spontaneous structure distortion can cause the long-sought, considerably large valley polarization. In detail, the physics of valley-orbital coupling, valley-orbital-layer coupling, valley-contrasting linear dichroism, and interlayer exciton valleytronics are discussed.
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Affiliation(s)
- Yushuo Xu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, People's Republic of China
| | - Yuanyuan Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, People's Republic of China
| | - Shuhua Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, People's Republic of China
| | - Shiqiang Yu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, People's Republic of China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, People's Republic of China
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, People's Republic of China
| | - Wei Wei
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan250100, People's Republic of China
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18
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Kim JS, Maity N, Kim M, Fu S, Juneja R, Singh A, Akinwande D, Lin JF. Strain-Modulated Interlayer Charge and Energy Transfers in MoS 2/WS 2 Heterobilayer. ACS APPLIED MATERIALS & INTERFACES 2022; 14:46841-46849. [PMID: 36195978 DOI: 10.1021/acsami.2c10982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Excitonic properties in 2D heterobilayers are closely governed by charge transfer (CT) and excitonic energy transfer (ET) at van der Waals interfaces. Various means have been employed to modulate the interlayer CT and ET, including electrical gating and modifying interlayer spacing, but with limited extent in their controllability. Here, we report a novel method to modulate these transfers in the MoS2/WS2 heterobilayer by applying compressive strain under hydrostatic pressure. Raman and photoluminescence measurements, combined with density functional theory calculations, show pressure-enhanced interlayer interaction of the heterobilayer. Heterobilayer-to-monolayer photoluminescence intensity ratio (η) of WS2 decreases by five times up to ≈4 GPa, suggesting enhanced ET, whereas it increases by an order of magnitude at higher pressures and reaches almost unity. Theoretical calculations show that orbital switching and charge transfers in the heterobilayer's hybridized conduction band are responsible for the non-monotonic modulation of the transfers. Our findings provide a compelling approach toward effective mechanical control of CT and ET in 2D excitonic devices.
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Affiliation(s)
- Joon-Seok Kim
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois60208, United States
- Microelectronics Research Center, The University of Texas at Austin, Austin, Texas78758, United States
| | - Nikhilesh Maity
- Materials Research Centre, Indian Institute of Science, Bangalore560012, India
| | - Myungsoo Kim
- Microelectronics Research Center, The University of Texas at Austin, Austin, Texas78758, United States
| | - Suyu Fu
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, AustinTexas78712, United States
| | - Rinkle Juneja
- Materials Research Centre, Indian Institute of Science, Bangalore560012, India
| | - Abhishek Singh
- Materials Research Centre, Indian Institute of Science, Bangalore560012, India
| | - Deji Akinwande
- Microelectronics Research Center, The University of Texas at Austin, Austin, Texas78758, United States
| | - Jung-Fu Lin
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, AustinTexas78712, United States
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19
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Yao W, Yang D, Chen Y, Hu J, Li J, Li D. Layer-Number Engineered Momentum-Indirect Interlayer Excitons with Large Spectral Tunability. NANO LETTERS 2022; 22:7230-7237. [PMID: 36036787 DOI: 10.1021/acs.nanolett.2c02742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Interlayer excitons (IXs) in type II van der Waals (vdW) heterostructures are equipped with an oriented permanent dipole moment and long lifetime and thus would allow promising applications in excitonic and optoelectronic devices. However, based on the widely studied heterostructures of transition-metal dichalcogenides (TMDs), IX emission is greatly influenced by the lattice mismatch and geometric misalignment between the constituent layers, increasing the complexity of the device fabrication. Here, we report on the robust momentum-indirect IX emission in TMD/two-dimensional (2D) perovskite vdW heterostructures, which were fabricated without considering the orientation arrangement or momentum mismatch. The IXs show a large diffusion coefficient of ∼10 cm2 s-1, and importantly the IX emission energy can be widely tuned from 1.3 to 1.6 eV via changing the layer number of the 2D perovskite or the thickness of TMD flakes, shedding light on the applications of vdW interface engineering to broad-spectrum optoelectronics.
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Affiliation(s)
- Wendian Yao
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Dong Yang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Yingying Chen
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Junchao Hu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Junze Li
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Dehui Li
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
- Wuhan National Laboratory for Optoelectronics, Optical Valley Laboratory, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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20
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Sharma A, Zhu Y, Halbich R, Sun X, Zhang L, Wang B, Lu Y. Engineering the Dynamics and Transport of Excitons, Trions, and Biexcitons in Monolayer WS 2. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41165-41177. [PMID: 36048513 DOI: 10.1021/acsami.2c08199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The study of transport and diffusion dynamics of quasi-particles such as excitons, trions, and biexcitons in two-dimensional (2D) semiconductors has opened avenues for their application in high-speed excitonic and optoelectronic devices. However, long-range transport and fast diffusion of these quasi-particles have not been reported for 2D systems such as transition metal dichalcogenides (TMDCs). The reported diffusion coefficients from TMDCs are low, limiting their use in high-speed excitonic devices and other optoelectronic applications. Here, we report the highest exciton diffusion coefficient value in monolayer WS2 achieved via engineering the radiative lifetime and diffusion lengths using static back-gate voltage and substrate engineering. Electrostatic doping is observed to modulate the radiative lifetime and in turn the diffusion coefficient of excitons by ∼three times at room temperature. By combining electrostatic doping and substrate engineering, we push the diffusion coefficient to an extremely high value of 86.5 cm2/s, which has not been reported before in TMDCs and is even higher than the values in some 1D systems. At low temperatures, we further report the control of dynamic and spatial diffusion of excitons, trions, and biexcitons from WS2. The electrostatic control of dynamics and transport of these quasi-particles in monolayers establishes monolayer TMDCs as ideal candidates for high-speed excitonic circuits, optoelectronic, and photonic device applications.
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Affiliation(s)
- Ankur Sharma
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Yi Zhu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
- Department of Engineering, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Robert Halbich
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Xueqian Sun
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Linglong Zhang
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Bowen Wang
- 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
- ARC Centre of Excellence in Quantum Computation and Communication Technology ANU Node, Canberra, ACT 2601, Australia
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21
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Shanks DN, Mahdikhanysarvejahany F, Stanfill TG, Koehler MR, Mandrus DG, Taniguchi T, Watanabe K, LeRoy BJ, Schaibley JR. Interlayer Exciton Diode and Transistor. NANO LETTERS 2022; 22:6599-6605. [PMID: 35969812 DOI: 10.1021/acs.nanolett.2c01905] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Controlling the flow of charge neutral interlayer exciton (IX) quasiparticles can potentially lead to low loss excitonic circuits. Here, we report unidirectional transport of IXs along nanoscale electrostatically defined channels in an MoSe2-WSe2 heterostructure. These results are enabled by a lithographically defined triangular etch in a graphene gate to create a potential energy "slide". By performing spatially and temporally resolved photoluminescence measurements, we measure smoothly varying IX energy along the structure and high speed exciton flow with a drift velocity up to 2 × 106 cm/s, an order of magnitude larger than previous experiments. Furthermore, exciton flow can be controlled by saturating exciton population in the channel using a second laser pulse, demonstrating an optically gated excitonic transistor. Our work paves the way toward low loss excitonic circuits, the study of bosonic transport in one-dimensional channels, and custom potential energy landscapes for excitons in van der Waals heterostructures.
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Affiliation(s)
- Daniel N Shanks
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
| | | | - Trevor G Stanfill
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
| | - Michael R Koehler
- IAMM Diffraction Facility, Institute for Advanced Materials and Manufacturing, University of Tennessee, Knoxville, Tennessee 37920, United States
| | - David G Mandrus
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Brian J LeRoy
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
| | - John R Schaibley
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
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22
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Wang CF, El-Khoury PZ. Resonant Coherent Raman Scattering from WSe 2. J Phys Chem A 2022; 126:5832-5836. [PMID: 35976736 DOI: 10.1021/acs.jpca.2c04120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Low-dimensional transition-metal dichalcogenides (TMDs) continue to comprise a subject of intense research because of their unique optical and electronic properties that may be harnessed in modern devices. Intense photoluminescence (PL) from few-/monolayer TMDs rendered PL-based micro- and nanospectroscopic characterization ideal in the quest to understand the correlation between structure and function in these materials. Nonlinear optical methods are by comparison far less utilized for this purpose. In this work, we describe an approach based on electronically resonant four-wave-mixing that allows spatio-spectral characterization of excitons in monolayer WSe2. Due to the coherent nature of the response that we exploit to trace exciton resonances, and recent demonstrations of electronic four-wave-mixing-based nanoimaging and nanospectroscopy, our present work is an important step toward characterizing TMDs on the nano-femto scale using light.
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Affiliation(s)
- Chih-Feng Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Patrick Z El-Khoury
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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23
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Liu Y, Elbanna A, Gao W, Pan J, Shen Z, Teng J. Interlayer Excitons in Transition Metal Dichalcogenide Semiconductors for 2D Optoelectronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107138. [PMID: 34700359 DOI: 10.1002/adma.202107138] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Optoelectronic materials that allow on-chip integrated light signal emitting, routing, modulation, and detection are crucial for the development of high-speed and high-throughput optical communication and computing technologies. Interlayer excitons in 2D van der Waals heterostructures, where electrons and holes are bounded by Coulomb interaction but spatially localized in different 2D layers, have recently attracted intense attention for their enticing properties and huge potential in device applications. Here, a general view of these 2D-confined hydrogen-like bosonic particles and the state-of-the-art developments with respect to the frontier concepts and prototypes is presented. Staggered type-II band alignment enables expansion of the interlayer direct bandgap from the intrinsic visible in monolayers up to the near- or even mid-infrared spectrum. Owing to large exciton binding energy, together with ultralong lifetime, room-temperature exciton devices and observation of quantum behaviors are demonstrated. With the rapid advances, it can be anticipated that future studies of interlayer excitons will not only allow the construction of all-exciton information processing circuits but will also continue to enrich the panoply of ideas on quantum phenomena.
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Affiliation(s)
- Yuanda Liu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Singapore
| | - Ahmed Elbanna
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 637371, Singapore
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 637371, Singapore
- The Photonics Institute and Center for Disruptive Photonic Technologies, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Jisheng Pan
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Singapore
| | - Zexiang Shen
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 637371, Singapore
- The Photonics Institute and Center for Disruptive Photonic Technologies, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Jinghua Teng
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Singapore
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24
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Su H, Xu D, Cheng SW, Li B, Liu S, Watanabe K, Taniguchi T, Berkelbach TC, Hone JC, Delor M. Dark-Exciton Driven Energy Funneling into Dielectric Inhomogeneities in Two-Dimensional Semiconductors. NANO LETTERS 2022; 22:2843-2850. [PMID: 35294835 DOI: 10.1021/acs.nanolett.1c04997] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The optoelectronic and transport properties of two-dimensional transition metal dichalcogenide semiconductors (2D TMDs) are highly susceptible to external perturbation, enabling precise tailoring of material function through postsynthetic modifications. Here, we show that nanoscale inhomogeneities known as nanobubbles can be used for both strain and, less invasively, dielectric tuning of exciton transport in bilayer tungsten diselenide (WSe2). We use ultrasensitive spatiotemporally resolved optical scattering microscopy to directly image exciton transport, revealing that dielectric nanobubbles are surprisingly efficient at funneling and trapping excitons at room temperature, even though the energies of the bright excitons are negligibly affected. Our observations suggest that exciton funneling in dielectric inhomogeneities is driven by momentum-indirect (dark) excitons whose energies are more sensitive to dielectric perturbations than bright excitons. These results reveal a new pathway to control exciton transport in 2D semiconductors with exceptional spatial and energetic precision using dielectric engineering of dark state energetic landscapes.
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Affiliation(s)
- Haowen Su
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Ding Xu
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Shan-Wen Cheng
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Baichang Li
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Song Liu
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | | | | | - Timothy C Berkelbach
- Department of Chemistry, Columbia University, New York, New York 10027, United States
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, United States
| | - James C Hone
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Milan Delor
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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25
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Abstract
AbstractExcitons are elementary optical excitation in semiconductors. The ability to manipulate and transport these quasiparticles would enable excitonic circuits and devices for quantum photonic technologies. Recently, interlayer excitons in 2D semiconductors have emerged as a promising candidate for engineering excitonic devices due to their long lifetime, large exciton binding energy, and gate tunability. However, the charge-neutral nature of the excitons leads to weak response to the in-plane electric field and thus inhibits transport beyond the diffusion length. Here, we demonstrate the directional transport of interlayer excitons in bilayer WSe2 driven by the propagating potential traps induced by surface acoustic waves (SAW). We show that at 100 K, the SAW-driven excitonic transport is activated above a threshold acoustic power and reaches 20 μm, a distance at least ten times longer than the diffusion length and only limited by the device size. Temperature-dependent measurement reveals the transition from the diffusion-limited regime at low temperature to the acoustic field-driven regime at elevated temperature. Our work shows that acoustic waves are an effective, contact-free means to control exciton dynamics and transport, promising for realizing 2D materials-based excitonic devices such as exciton transistors, switches, and transducers up to room temperature.
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26
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Sun Z, Ciarrocchi A, Tagarelli F, Marin JFG, Watanabe K, Taniguchi T, Kis A. Excitonic transport driven by repulsive dipolar interaction in a van der Waals heterostructure. NATURE PHOTONICS 2022; 16:79-85. [PMID: 34992677 PMCID: PMC7612161 DOI: 10.1038/s41566-021-00908-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Dipolar bosonic gases are currently the focus of intensive research due to their interesting many-body physics in the quantum regime. Their experimental embodiments range from Rydberg atoms to GaAs double quantum wells and van der Waals heterostructures built from transition metal dichalcogenides. Although quantum gases are very dilute, mutual interactions between particles could lead to exotic many-body phenomena such as Bose-Einstein condensation and high-temperature superfluidity. Here, we report the effect of repulsive dipolar interactions on the dynamics of interlayer excitons in the dilute regime. By using spatial and time-resolved photoluminescence imaging, we observe the dynamics of exciton transport, enabling a direct estimation of the exciton mobility. The presence of interactions significantly modifies the diffusive transport of excitons, effectively acting as a source of drift force and enhancing the diffusion coefficient by one order of magnitude. The repulsive dipolar interactions combined with the electrical control of interlayer excitons opens up appealing new perspectives for excitonic devices.
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Affiliation(s)
- Zhe Sun
- Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Correspondence should be addressed to: Zhe Sun () and Andras Kis ()
| | - Alberto Ciarrocchi
- Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Fedele Tagarelli
- Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Juan Francisco Gonzalez Marin
- Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Andras Kis
- Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Correspondence should be addressed to: Zhe Sun () and Andras Kis ()
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27
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Kim JM, Haque MF, Hsieh EY, Nahid SM, Zarin I, Jeong KY, So JP, Park HG, Nam S. Strain Engineering of Low-Dimensional Materials for Emerging Quantum Phenomena and Functionalities. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021:e2107362. [PMID: 34866241 DOI: 10.1002/adma.202107362] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/11/2021] [Indexed: 06/13/2023]
Abstract
Recent discoveries of exotic physical phenomena, such as unconventional superconductivity in magic-angle twisted bilayer graphene, dissipationless Dirac fermions in topological insulators, and quantum spin liquids, have triggered tremendous interest in quantum materials. The macroscopic revelation of quantum mechanical effects in quantum materials is associated with strong electron-electron correlations in the lattice, particularly where materials have reduced dimensionality. Owing to the strong correlations and confined geometry, altering atomic spacing and crystal symmetry via strain has emerged as an effective and versatile pathway for perturbing the subtle equilibrium of quantum states. This review highlights recent advances in strain-tunable quantum phenomena and functionalities, with particular focus on low-dimensional quantum materials. Experimental strategies for strain engineering are first discussed in terms of heterogeneity and elastic reconfigurability of strain distribution. The nontrivial quantum properties of several strain-quantum coupled platforms, including 2D van der Waals materials and heterostructures, topological insulators, superconducting oxides, and metal halide perovskites, are next outlined, with current challenges and future opportunities in quantum straintronics followed. Overall, strain engineering of quantum phenomena and functionalities is a rich field for fundamental research of many-body interactions and holds substantial promise for next-generation electronics capable of ultrafast, dissipationless, and secure information processing and communications.
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Affiliation(s)
- Jin Myung Kim
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Md Farhadul Haque
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Ezekiel Y Hsieh
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Shahriar Muhammad Nahid
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Ishrat Zarin
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Kwang-Yong Jeong
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
- Department of Physics, Jeju National University, Jeju, 63243, Republic of Korea
| | - Jae-Pil So
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
| | - Hong-Gyu Park
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul, 02841, Republic of Korea
| | - SungWoo Nam
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Department of Mechanical and Aerospace Engineering, University of California Irvine, Irvine, CA, 92697, USA
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28
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A compact device sustains a fluid of bosons. Nature 2021. [DOI: 10.1038/d41586-021-02876-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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29
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Cheng G, Li B, Jin Z, Zhang M, Wang J. Observation of Diffusion and Drift of the Negative Trions in Monolayer WS 2. NANO LETTERS 2021; 21:6314-6320. [PMID: 34250802 DOI: 10.1021/acs.nanolett.1c02351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Monolayer transition metal dichalcogenides (ML-TMDCs) are a versatile platform to explore the transport dynamics of the tightly bound excitonic states. The diffusion of neutral excitons in various ML-TMDCs has been observed. However, the transport of charged excitons (trions), which can be driven by an in-plane electric field and facilitate the formation of an excitonic current, has yet been well investigated. Here, we report the direct observation of diffusion and drift of the trions in ML-WS2 through spatially and time-resolved photoluminescence. An effective diffusion coefficient of 0.47 cm2/s was extracted from the broadening of spatial profiles of the trion emission. When an in-plane electric field is applied, the spatial shift of the trion emission profiles indicated a drift velocity of 7400 cm/s. Both the diffusion caused broadening and the drift caused shift of the emission profiles saturate because of the Coulomb interactions between trions and the background charges.
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Affiliation(s)
- Guanghui Cheng
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
- Department of Physics and Astronomy, Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, United States
- WPI Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
| | - Baikui Li
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Zijing Jin
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Meng Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Jiannong Wang
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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30
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Liu Y, Zeng C, Yu J, Zhong J, Li B, Zhang Z, Liu Z, Wang ZM, Pan A, Duan X. Moiré superlattices and related moiré excitons in twisted van der Waals heterostructures. Chem Soc Rev 2021; 50:6401-6422. [PMID: 33942837 DOI: 10.1039/d0cs01002b] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recent advances in moiré superlattices and moiré excitons, such as quantum emission arrays, low-energy flat bands, and Mott insulators, have rapidly attracted attention in the fields of optoelectronics, materials, and energy research. The interlayer twist turns into a degree of freedom that alters the properties of the systems of materials, and the realization of moiré excitons also offers the feasibility of making artificial exciton crystals. Moreover, moiré excitons exhibit many exciting properties under the regulation of various external conditions, including spatial polarisation, alternating dipolar to alternating dipolar moments and gate-dependence to gate voltage dependence; all are pertinent to their applications in nano-photonics and quantum information. But the lag in theoretical development and the low-efficiency of processing technologies significantly limit the potential of moiré superlattice applications. In this review, we systematically summarise and discuss the recent progress in moiré superlattices and moiré excitons, and analyze the current challenges, and put forward relevant recommendations. There is no doubt that further research will lead to breakthroughs in their application and promote reforms and innovations in traditional solid-state physics and materials science.
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Affiliation(s)
- 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.
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31
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Halder O, Mallik G, Suffczyński J, Pacuski W, Varadwaj KSK, Satpati B, Rath S. Enhanced exciton binding energy, Zeeman splitting and spin polarization in hybrid layered nanosheets comprised of (Cd, Mn)Se and nitrogen-doped graphene oxide: implication for semiconductor devices. NANOTECHNOLOGY 2021; 32:325204. [PMID: 33946057 DOI: 10.1088/1361-6528/abfdee] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
The exciton properties of (Cd,Mn)Se-NrGO (nitrogen doped reduced graphene oxide) hybrid layered nanosheets have been studied in a magnetic field up to 10 T and compared to those of (Cd,Mn)Se nanosheets. The temperature dependent photoluminescence reveals the hybridization of inter-band exciton and intra-center Mn transition with enhancement of the binding energy of exciton-Mn hybridized state (80 meV with respect to 60 meV in (Cd,Mn)Se nanosheets) and increase of exciton-phonon coupling strength to 90 meV (with respect to 55 meV in (Cd,Mn)Se nanosheets). The circularly polarized magneto-photoluminescence at 2 K provides evidence for magnetic field induced exciton spin polarization and the realization of excitonic giant Zeeman splitting withgeffas high as 165.4 ± 10.3, much larger than in the case of (Cd,Mn)Se nanosheets (63.9 ± 6.6), promising for implementation in spin active semiconductor devices.
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Affiliation(s)
- Oindrila Halder
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Jatni, Khordha 752050, India
| | - Gyanadeep Mallik
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Jatni, Khordha 752050, India
| | - Jan Suffczyński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, Warsaw 02 093, Poland
| | - Wojciech Pacuski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, Warsaw 02 093, Poland
| | | | - Biswarup Satpati
- Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Satchidananda Rath
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Jatni, Khordha 752050, India
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32
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Abstract
Interlayer excitons in van der Waals heterostructures have tunable electron-hole separation in both real space and momentum space, enabling unprecedented control over excitonic properties to be exploited in a wide array of future applications ranging from exciton condensation to valleytronic and optoelectronic devices.
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Affiliation(s)
- Kai-Qiang Lin
- Department of Physics, University of Regensburg, Regensburg, Germany.
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33
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Jiang Y, Chen S, Zheng W, Zheng B, Pan A. Interlayer exciton formation, relaxation, and transport in TMD van der Waals heterostructures. LIGHT, SCIENCE & APPLICATIONS 2021; 10:72. [PMID: 33811214 PMCID: PMC8018964 DOI: 10.1038/s41377-021-00500-1] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/08/2021] [Accepted: 02/24/2021] [Indexed: 05/06/2023]
Abstract
Van der Waals (vdW) heterostructures based on transition metal dichalcogenides (TMDs) generally possess a type-II band alignment that facilitates the formation of interlayer excitons between constituent monolayers. Manipulation of the interlayer excitons in TMD vdW heterostructures holds great promise for the development of excitonic integrated circuits that serve as the counterpart of electronic integrated circuits, which allows the photons and excitons to transform into each other and thus bridges optical communication and signal processing at the integrated circuit. As a consequence, numerous studies have been carried out to obtain deep insight into the physical properties of interlayer excitons, including revealing their ultrafast formation, long population recombination lifetimes, and intriguing spin-valley dynamics. These outstanding properties ensure interlayer excitons with good transport characteristics, and may pave the way for their potential applications in efficient excitonic devices based on TMD vdW heterostructures. At present, a systematic and comprehensive overview of interlayer exciton formation, relaxation, transport, and potential applications is still lacking. In this review, we give a comprehensive description and discussion of these frontier topics for interlayer excitons in TMD vdW heterostructures to provide valuable guidance for researchers in this field.
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Affiliation(s)
- Ying Jiang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China
| | - Shula Chen
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
| | - Weihao Zheng
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China
| | - Biyuan Zheng
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China.
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34
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Koo Y, Kim Y, Choi SH, Lee H, Choi J, Lee DY, Kang M, Lee HS, Kim KK, Lee G, Park KD. Tip-Induced Nano-Engineering of Strain, Bandgap, and Exciton Funneling in 2D Semiconductors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008234. [PMID: 33709476 DOI: 10.1002/adma.202008234] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/04/2021] [Indexed: 06/12/2023]
Abstract
The tunability of the bandgap, absorption and emission energies, photoluminescence (PL) quantum yield, exciton transport, and energy transfer in transition metal dichalcogenide (TMD) monolayers provides a new class of functions for a wide range of ultrathin photonic devices. Recent strain-engineering approaches have enabled to tune some of these properties, yet dynamic control at the nanoscale with real-time and -space characterizations remains a challenge. Here, a dynamic nano-mechanical strain-engineering of naturally-formed wrinkles in a WSe2 monolayer, with real-time investigation of nano-spectroscopic properties is demonstrated using hyperspectral adaptive tip-enhanced PL (a-TEPL) spectroscopy. First, nanoscale wrinkles are characterized through hyperspectral a-TEPL nano-imaging with <15 nm spatial resolution, which reveals the modified nano-excitonic properties by the induced tensile strain at the wrinkle apex, for example, an increase in the quantum yield due to the exciton funneling, decrease in PL energy up to ≈10 meV, and a symmetry change in the TEPL spectra caused by the reconfigured electronic bandstructure. Then the local strain is dynamically engineered by pressing and releasing the wrinkle apex through an atomic force tip control. This nano-mechanical strain-engineering allows to tune the exciton dynamics and emission properties at the nanoscale in a reversible fashion. In addition, a systematic switching and modulation platform of the wrinkle emission is demonstrated, which provides a new strategy for robust, tunable, and ultracompact nano-optical sources in atomically thin semiconductors.
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Affiliation(s)
- Yeonjeong Koo
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Yongchul Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Soo Ho Choi
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Hyeongwoo Lee
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jinseong Choi
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Dong Yun Lee
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Mingu Kang
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hyun Seok Lee
- Department of Physics, Research Institute for Nanoscale Science and Technology, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - Ki Kang Kim
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon, 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Geunsik Lee
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Center for Wave Energy Materials, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Kyoung-Duck Park
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
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35
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Ye T, Zhou B, Liu Z, Li Y, Shen H, Ning CZ, Li D. Room-Temperature Exciton-Based Optoelectronic Switch. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2005918. [PMID: 33432674 DOI: 10.1002/smll.202005918] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/29/2020] [Indexed: 06/12/2023]
Abstract
Excitons, bound pairs of electrons and holes, could act as an intermediary between electronic signal processing and optical transmission, thus speeding up the interconnection of photoelectric communication. However, up to date, exciton-based logic devices such as switches that work at room temperature are still lacking. This work presents a prototype of a room-temperature optoelectronic switch based on excitons in WSe2 monolayer. The emission intensity of WSe2 stacked on Au and SiO2 substrates exhibits completely opposite behaviors upon applying gate voltages. Such observation can be ascribed to different doping behaviors of WSe2 caused by charge-transfer and chemical-doping effect at WSe2 /Au and WSe2 /SiO2 interfaces, respectively, together with the charge-drift effect. These interesting features can be utilized for optoelectronic switching, confirmed by the cyclic PL switching test for a long time exceeding 4000 s. This study offers a universal and reliable approach for the fabrication of exciton-based optoelectronic switches, which would be essential in integrated nanophotonics.
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Affiliation(s)
- Tong Ye
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Boxuan Zhou
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zeyi Liu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yongzhuo Li
- Department of Electronic Engineering, Tsinghua University, Beijing, 100084, China
- Frontier Science Center for Quantum Information, Beijing, 100084, China
- Beijing National Research Center for Information Science and Technology, Beijing, 100084, China
| | - Hongzhi Shen
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Cun-Zheng Ning
- Department of Electronic Engineering, Tsinghua University, Beijing, 100084, China
- Frontier Science Center for Quantum Information, Beijing, 100084, China
- Beijing National Research Center for Information Science and Technology, Beijing, 100084, China
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Dehui Li
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
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36
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Lee J, Yun SJ, Seo C, Cho K, Kim TS, An GH, Kang K, Lee HS, Kim J. Switchable, Tunable, and Directable Exciton Funneling in Periodically Wrinkled WS 2. NANO LETTERS 2021; 21:43-50. [PMID: 33052049 DOI: 10.1021/acs.nanolett.0c02619] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The extreme elastic strain of monolayer transition metal dichalcogenides provides an ideal platform to achieve efficient exciton funneling via local strain modulation; however, studies conducted thus far have focused on the use of substrates with fixed strain profiles. We prepared 1L-WS2 on a flexible substrate such that the formation of topographic wrinkles could be switched on or off, and the depth or the direction of the wrinkle could be modified by external strain, thereby providing full control of the periodic undulation of the band gap profile of 1L-WS2 in the range 0-57 meV. Nanoscale photoluminescence (PL) imaging unambiguously evinced that the photoexcited excitons of 1L-WS2 were accumulated at the top regions of the wrinkles with less band gap than the valley region. Our results of broad tunability of the two-dimensional (2D) exciton funneling suggest a promising route to control exciton drift for enhanced optoelectronic performances and future 2D exciton devices.
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Affiliation(s)
- Jubok Lee
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seok Joon Yun
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
| | - Changwon Seo
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
| | - Kiwon Cho
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Tae Soo Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Gwang Hwi An
- Department of Physics, Research Institute for Nanoscale Science and Technology, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Kibum Kang
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Hyun Seok Lee
- Department of Physics, Research Institute for Nanoscale Science and Technology, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
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37
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Uddin SZ, Kim H, Lorenzon M, Yeh M, Lien DH, Barnard ES, Htoon H, Weber-Bargioni A, Javey A. Neutral Exciton Diffusion in Monolayer MoS 2. ACS NANO 2020; 14:13433-13440. [PMID: 32909735 DOI: 10.1021/acsnano.0c05305] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Monolayer transition metal dichalcogenides (TMDCs) are promising materials for next generation optoelectronic devices. The exciton diffusion length is a critical parameter that reflects the quality of exciton transport in monolayer TMDCs and limits the performance of many excitonic devices. Although diffusion lengths of a few hundred nanometers have been reported in the literature for as-exfoliated monolayers, these measurements are convoluted by neutral and charged excitons (trions) that coexist at room temperature due to natural background doping. Untangling the diffusion of neutral excitons and trions is paramount to understand the fundamental limits and potential of new optoelectronic device architectures made possible using TMDCs. In this work, we measure the diffusion lengths of neutral excitons and trions in monolayer MoS2 by tuning the background carrier concentration using a gate voltage and utilizing both steady state and transient spectroscopy. We observe diffusion lengths of 1.5 μm and 300 nm for neutral excitons and trions, respectively, at an optical power density of 0.6 W cm-2.
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Affiliation(s)
- Shiekh Zia Uddin
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United State
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Hyungjin Kim
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United State
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Monica Lorenzon
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Matthew Yeh
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United State
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Der-Hsien Lien
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United State
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Edward S Barnard
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Han Htoon
- Center for Integrated Nanotechnologies, Material Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Alexander Weber-Bargioni
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ali Javey
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United State
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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38
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Marino E, Sciortino A, Berkhout A, MacArthur KE, Heggen M, Gregorkiewicz T, Kodger TE, Capretti A, Murray CB, Koenderink AF, Messina F, Schall P. Simultaneous Photonic and Excitonic Coupling in Spherical Quantum Dot Supercrystals. ACS NANO 2020; 14:13806-13815. [PMID: 32924433 PMCID: PMC7596773 DOI: 10.1021/acsnano.0c06188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Semiconductor nanocrystals, or quantum dots (QDs), simultaneously benefit from inexpensive low-temperature solution processing and exciting photophysics, making them the ideal candidates for next-generation solar cells and photodetectors. While the working principles of these devices rely on light absorption, QDs intrinsically belong to the Rayleigh regime and display optical behavior limited to electric dipole resonances, resulting in low absorption efficiencies. Increasing the absorption efficiency of QDs, together with their electronic and excitonic coupling to enhance charge carrier mobility, is therefore of critical importance to enable practical applications. Here, we demonstrate a general and scalable approach to increase both light absorption and excitonic coupling of QDs by fabricating hierarchical metamaterials. We assemble QDs into crystalline supraparticles using an emulsion template and demonstrate that these colloidal supercrystals (SCs) exhibit extended resonant optical behavior resulting in an enhancement in absorption efficiency in the visible range of more than 2 orders of magnitude with respect to the case of dispersed QDs. This successful light trapping strategy is complemented by the enhanced excitonic coupling observed in ligand-exchanged SCs, experimentally demonstrated through ultrafast transient absorption spectroscopy and leading to the formation of a free biexciton system on sub-picosecond time scales. These results introduce a colloidal metamaterial designed by self-assembly from the bottom up, simultaneously featuring a combination of nanoscale and mesoscale properties leading to simultaneous photonic and excitonic coupling, therefore presenting the nanocrystal analogue of supramolecular structures.
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Affiliation(s)
- Emanuele Marino
- Van
der Waals−Zeeman Institute, University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
- Department
of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, Pennsylvania 19104, United States
| | - Alice Sciortino
- Dipartimento
di Fisica e Chimica−Emilio Segrè, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo, Italy
| | - Annemarie Berkhout
- Center
for Nanophotonics, AMOLF, Science Park 104, 1098XG Amsterdam, The Netherlands
| | - Katherine E. MacArthur
- Ernst
Ruska Centre for Microscopy and Spectroscopy with Electrons and Peter
Grünberg Institute, Forschungszentrum
Jülich GmbH, 52425 Jülich, Germany
| | - Marc Heggen
- Ernst
Ruska Centre for Microscopy and Spectroscopy with Electrons and Peter
Grünberg Institute, Forschungszentrum
Jülich GmbH, 52425 Jülich, Germany
| | - Tom Gregorkiewicz
- Van
der Waals−Zeeman Institute, University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Thomas E. Kodger
- Van
der Waals−Zeeman Institute, University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
- Physical
Chemistry and Soft Matter, Wageningen University
and Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Antonio Capretti
- Van
der Waals−Zeeman Institute, University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Christopher B. Murray
- Department
of Chemistry, University of Pennsylvania, 231 S. 34th St., Philadelphia, Pennsylvania 19104, United States
- Department
of Materials Science and Engineering, University
of Pennsylvania, 220
S 33rd St., Philadelphia, Pennsylvania 19104, United States
| | - A. Femius Koenderink
- Van
der Waals−Zeeman Institute, University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
- Center
for Nanophotonics, AMOLF, Science Park 104, 1098XG Amsterdam, The Netherlands
| | - Fabrizio Messina
- Dipartimento
di Fisica e Chimica−Emilio Segrè, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo, Italy
| | - Peter Schall
- Van
der Waals−Zeeman Institute, University
of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
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39
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Liu Y, Dini K, Tan Q, Liew T, Novoselov KS, Gao W. Electrically controllable router of interlayer excitons. SCIENCE ADVANCES 2020; 6:6/41/eaba1830. [PMID: 33028515 PMCID: PMC7541059 DOI: 10.1126/sciadv.aba1830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 08/19/2020] [Indexed: 05/24/2023]
Abstract
Optoelectronic devices that allow rerouting, modulation, and detection of the optical signals would be extremely beneficial for telecommunication technology. One of the most promising platforms for these devices is excitonic devices, as they offer very efficient coupling to light. Of especial importance are those based on indirect excitons because of their long lifetime. Here, we demonstrate excitonic transistor and router based on bilayer WSe2 Because of their strong dipole moment, excitons in bilayer WSe2 can be controlled by transverse electric field. At the same time, unlike indirect excitons in artificially stacked heterostructures based on transition metal dichalcogenides, naturally stacked bilayers are much simpler in fabrication.
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Affiliation(s)
- Yuanda Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore
| | - Kévin Dini
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Qinghai Tan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Timothy Liew
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Kostya S Novoselov
- Department of Material Science and Engineering, National University of Singapore, 117575, Singapore.
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore
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40
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Yu H, Yao W. Electrically tunable topological transport of moiré polaritons. Sci Bull (Beijing) 2020; 65:1555-1562. [PMID: 36738073 DOI: 10.1016/j.scib.2020.05.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/07/2020] [Accepted: 05/25/2020] [Indexed: 02/07/2023]
Abstract
Moiré interlayer exciton in transition metal dichalcogenide heterobilayer features a permanent electric dipole that enables the electrostatic control of its flow, and optical dipole that is spatially varying in the moiré landscape. We show the hybridization of moiré interlayer exciton with photons in a planar 2D cavity leads to two types of moiré polaritons that exhibit distinct forms of topological transport phenomena including the spin/valley Hall and polarization Hall effects, which feature remarkable electrical tunability through the control of exciton-cavity detuning by the interlayer bias.
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Affiliation(s)
- Hongyi Yu
- Guangdong Provincial Key Laboratory of Quantum Metrology and Sensing & School of Physics and Astronomy, Sun Yat-sen University (Zhuhai Campus), Zhuhai 519082, China; Department of Physics, The University of Hong Kong, Hong Kong, China.
| | - Wang Yao
- Department of Physics, The University of Hong Kong, Hong Kong, China; HKU-UCAS Joint Institute of Theoretical and Computational Physics at Hong Kong, Hong Kong, China.
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41
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Moon H, Grosso G, Chakraborty C, Peng C, Taniguchi T, Watanabe K, Englund D. Dynamic Exciton Funneling by Local Strain Control in a Monolayer Semiconductor. NANO LETTERS 2020; 20:6791-6797. [PMID: 32790415 DOI: 10.1021/acs.nanolett.0c02757] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ability to control excitons in semiconductors underlies numerous proposed applications, from excitonic circuits to energy transport. Two dimensional (2D) semiconductors are particularly promising for room-temperature applications due to their large exciton binding energy and enormous stretchability. Although the strain-induced static exciton flux has been observed in predetermined structures, dynamic control of exciton flux represents an outstanding challenge. Here, we introduce a method to tune the bandgap of suspended 2D semiconductors by applying a local strain gradient with a nanoscale tip. This strain allows us to locally and reversibly shift the exciton energy and to steer the exciton flux over micrometer-scale distances. We anticipate that our result not only marks an important experimental tool but will also open a broad range of new applications from information processing to energy conversion.
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Affiliation(s)
- Hyowon Moon
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
| | - Gabriele Grosso
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York, United States
- Physics Program, Graduate Center, City University of New York, New York, New York, United States
| | - Chitraleema Chakraborty
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, United States
| | - Cheng Peng
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
| | | | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki, Japan
| | - Dirk Englund
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
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42
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Sharma A, Zhang L, Tollerud JO, Dong M, Zhu Y, Halbich R, Vogl T, Liang K, Nguyen HT, Wang F, Sanwlani S, Earl SK, Macdonald D, Lam PK, Davis JA, Lu Y. Supertransport of excitons in atomically thin organic semiconductors at the 2D quantum limit. LIGHT, SCIENCE & APPLICATIONS 2020; 9:116. [PMID: 32655861 PMCID: PMC7338549 DOI: 10.1038/s41377-020-00347-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 05/14/2020] [Accepted: 06/09/2020] [Indexed: 05/20/2023]
Abstract
Long-range and fast transport of coherent excitons is important for the development of high-speed excitonic circuits and quantum computing applications. However, most of these coherent excitons have only been observed in some low-dimensional semiconductors when coupled with cavities, as there are large inhomogeneous broadening and dephasing effects on the transport of excitons in their native states in materials. Here, by confining coherent excitons at the 2D quantum limit, we first observed molecular aggregation-enabled 'supertransport' of excitons in atomically thin two-dimensional (2D) organic semiconductors between coherent states, with a measured high effective exciton diffusion coefficient of ~346.9 cm2/s at room temperature. This value is one to several orders of magnitude higher than the values reported for other organic molecular aggregates and low-dimensional inorganic materials. Without coupling to any optical cavities, the monolayer pentacene sample, a very clean 2D quantum system (~1.2 nm thick) with high crystallinity (J-type aggregation) and minimal interfacial states, showed superradiant emission from Frenkel excitons, which was experimentally confirmed by the temperature-dependent photoluminescence (PL) emission, highly enhanced radiative decay rate, significantly narrowed PL peak width and strongly directional in-plane emission. The coherence in monolayer pentacene samples was observed to be delocalised over ~135 molecules, which is significantly larger than the values (a few molecules) observed for other organic thin films. In addition, the supertransport of excitons in monolayer pentacene samples showed highly anisotropic behaviour. Our results pave the way for the development of future high-speed excitonic circuits, fast OLEDs, and other optoelectronic devices.
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Affiliation(s)
- Ankur Sharma
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Linglong Zhang
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Jonathan O. Tollerud
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
| | - Miheng Dong
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Yi Zhu
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Robert Halbich
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Tobias Vogl
- Centre for Quantum Computation and Communication Technology, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, ACT 2601 Australia
| | - Kun Liang
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, 100081 China
| | - Hieu T. Nguyen
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Fan Wang
- Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW 2007 Australia
| | - Shilpa Sanwlani
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
| | - Stuart K. Earl
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
| | - Daniel Macdonald
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Ping Koy Lam
- Centre for Quantum Computation and Communication Technology, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, ACT 2601 Australia
| | - Jeffrey A. Davis
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
| | - Yuerui Lu
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
- Centre for Quantum Computation and Communication Technology, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, ACT 2601 Australia
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43
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Qi P, Luo Y, Li W, Cheng Y, Shan H, Wang X, Liu Z, Ajayan PM, Lou J, Hou Y, Liu K, Fang Z. Remote Lightening and Ultrafast Transition: Intrinsic Modulation of Exciton Spatiotemporal Dynamics in Monolayer MoS 2. ACS NANO 2020; 14:6897-6905. [PMID: 32491833 DOI: 10.1021/acsnano.0c01165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Devices operating with excitons have promising prospects for overcoming the dilemma of response time and integration in current generation of electron- or/and photon-based elements and devices. Although the intrinsic properties including edges, grain boundaries, and defects of atomically thin semiconductors have been demonstrated as a powerful tool to adjust the bandgap and exciton energy, investigating the intrinsic modulation of spatiotemporal dynamics still remains challenging on account of the short exciton diffusion length. Here, we achieve the attractive remote lightening phenomenon, in which the emission region could be far away (up to 14.6 μm) from the excitation center, by utilizing a femtosecond laser with ultrahigh peak power as excitation source and the edge region with high photoluminescence efficiency as a bright emitter. Furthermore, the ultrafast transition between exciton and trion is demonstrated, which provides insight into the intrinsic modulation on populations of exciton and trion states. The complete cascaded physical scenario of exciton spatiotemporal dynamics is eventually established. This work can refresh our perspective on the spatial nonuniformities of CVD-grown atomically thin semiconductors and provide important implications for developing durable and stable excitonic devices in the future.
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Affiliation(s)
- Pengfei Qi
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
| | - Yang Luo
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
| | - Wei Li
- Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Centre for Engineering Science and Advanced Technology, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Yang Cheng
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
| | - Hangyong Shan
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
| | - Xingli Wang
- CNRS International-NTU-Thales Research Alliance (CINTRA), Nanyang Technological University, Singapore 637553, Singapore
| | - Zheng Liu
- CNRS International-NTU-Thales Research Alliance (CINTRA), Nanyang Technological University, Singapore 637553, Singapore
| | - Pulickel M Ajayan
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Jun Lou
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Yanglong Hou
- Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Centre for Engineering Science and Advanced Technology, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Kaihui Liu
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
| | - Zheyu Fang
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
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44
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Yuan L, Zheng B, Kunstmann J, Brumme T, Kuc AB, Ma C, Deng S, Blach D, Pan A, Huang L. Twist-angle-dependent interlayer exciton diffusion in WS 2-WSe 2 heterobilayers. NATURE MATERIALS 2020; 19:617-623. [PMID: 32393806 DOI: 10.1038/s41563-020-0670-3] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 03/25/2020] [Indexed: 05/12/2023]
Abstract
The nanoscale periodic potentials introduced by moiré patterns in semiconducting van der Waals heterostructures have emerged as a platform for designing exciton superlattices. However, our understanding of the motion of excitons in moiré potentials is still limited. Here we investigated interlayer exciton dynamics and transport in WS2-WSe2 heterobilayers in time, space and momentum domains using transient absorption microscopy combined with first-principles calculations. We found that the exciton motion is modulated by twist-angle-dependent moiré potentials around 100 meV and deviates from normal diffusion due to the interplay between the moiré potentials and strong exciton-exciton interactions. Our experimental results verified the theoretical prediction of energetically favourable K-Q interlayer excitons and showed exciton-population dynamics that are controlled by the twist-angle-dependent energy difference between the K-Q and K-K excitons. These results form a basis to investigate exciton and spin transport in van der Waals heterostructures, with implications for the design of quantum communication devices.
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Affiliation(s)
- Long Yuan
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Biyuan Zheng
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Materials Science and Engineering, Hunan University, Changsha, People's Republic of China
| | - Jens Kunstmann
- Theoretical Chemistry, Department of Chemistry and Food Chemistry, TU Dresden, Dresden, Germany
| | - Thomas Brumme
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Leipzig, Germany
| | - Agnieszka Beata Kuc
- Abteilung Ressourcenökologie, Helmholtz-Zentrum Dresden-Rossendorf, Forschungsstelle Leipzig, Leipzig, Germany
- Department of Physics & Earth Science, Jacobs University Bremen, Bremen, Germany
| | - Chao Ma
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Materials Science and Engineering, Hunan University, Changsha, People's Republic of China
| | - Shibin Deng
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Daria Blach
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Materials Science and Engineering, Hunan University, Changsha, People's Republic of China
| | - Libai Huang
- Department of Chemistry, Purdue University, West Lafayette, IN, USA.
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45
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Calman EV, Fowler-Gerace LH, Choksy DJ, Butov LV, Nikonov DE, Young IA, Hu S, Mishchenko A, Geim AK. Indirect Excitons and Trions in MoSe 2/WSe 2 van der Waals Heterostructures. NANO LETTERS 2020; 20:1869-1875. [PMID: 32069058 DOI: 10.1021/acs.nanolett.9b05086] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Indirect excitons (IX) in semiconductor heterostructures are bosons, which can cool below the temperature of quantum degeneracy and can be effectively controlled by voltage and light. IX quantum Bose gases and IX devices were explored in GaAs heterostructures where an IX range of existence is limited to low temperatures due to low IX binding energies. IXs in van der Waals transition-metal dichalcogenide (TMD) heterostructures are characterized by large binding energies giving the opportunity for exploring excitonic quantum gases and for creating excitonic devices at high temperatures. TMD heterostructures also offer a new platform for studying single-exciton phenomena and few-particle complexes. In this work, we present studies of IXs in MoSe2/WSe2 heterostructures and report on two IX luminescence lines whose energy splitting and temperature dependence identify them as neutral and charged IXs. The experimentally found binding energy of the indirect charged excitons, that is, indirect trions, is close to the calculated binding energy of 28 meV for negative indirect trions in TMD heterostructures [Deilmann, T.; Thygesen, K. S. Nano Lett. 2018, 18, 1460]. We also report on the realization of IXs with a luminescence line width reaching 4 meV at low temperatures. An enhancement of IX luminescence intensity and the narrow line width are observed in localized spots.
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Affiliation(s)
- E V Calman
- Department of Physics, University of California at San Diego, La Jolla, California 92093, United States
| | - L H Fowler-Gerace
- Department of Physics, University of California at San Diego, La Jolla, California 92093, United States
| | - D J Choksy
- Department of Physics, University of California at San Diego, La Jolla, California 92093, United States
| | - L V Butov
- Department of Physics, University of California at San Diego, La Jolla, California 92093, United States
| | - D E Nikonov
- Components Research, Intel Corporation, Hillsboro, Oregon 97124 United States
| | - I A Young
- Components Research, Intel Corporation, Hillsboro, Oregon 97124 United States
| | - S Hu
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - A Mishchenko
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - A K Geim
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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46
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Yu J, Sharma M, Sharma A, Delikanli S, Volkan Demir H, Dang C. All-optical control of exciton flow in a colloidal quantum well complex. LIGHT, SCIENCE & APPLICATIONS 2020; 9:27. [PMID: 32140218 PMCID: PMC7046609 DOI: 10.1038/s41377-020-0262-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 05/08/2023]
Abstract
Excitonics, an alternative to romising for processing information since semiconductor electronics is rapidly approaching the end of Moore's law. Currently, the development of excitonic devices, where exciton flow is controlled, is mainly focused on electric-field modulation or exciton polaritons in high-Q cavities. Here, we show an all-optical strategy to manipulate the exciton flow in a binary colloidal quantum well complex through mediation of the Förster resonance energy transfer (FRET) by stimulated emission. In the spontaneous emission regime, FRET naturally occurs between a donor and an acceptor. In contrast, upon stronger excitation, the ultrafast consumption of excitons by stimulated emission effectively engineers the excitonic flow from the donors to the acceptors. Specifically, the acceptors' stimulated emission significantly accelerates the exciton flow, while the donors' stimulated emission almost stops this process. On this basis, a FRET-coupled rate equation model is derived to understand the controllable exciton flow using the density of the excited donors and the unexcited acceptors. The results will provide an effective all-optical route for realizing excitonic devices under room temperature operation.
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Affiliation(s)
- Junhong Yu
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
| | - Manoj Sharma
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, 06800 Ankara Turkey
| | - Ashma Sharma
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
| | - Savas Delikanli
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, 06800 Ankara Turkey
| | - Hilmi Volkan Demir
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, 06800 Ankara Turkey
- School of Physical and Mathematical Sciences, Division of Physics and Applied Physics, Nanyang Technological University, 639798 Singapore, Singapore
| | - Cuong Dang
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
- CINTRA UMI CNRS/NTU/THALES 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, 637553 Singapore, Singapore
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47
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Huang Z, Liu Y, Dini K, Tan Q, Liu Z, Fang H, Liu J, Liew T, Gao W. Robust Room Temperature Valley Hall Effect of Interlayer Excitons. NANO LETTERS 2020; 20:1345-1351. [PMID: 31889447 DOI: 10.1021/acs.nanolett.9b04836] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The Berry curvature in the band structure of transition metal dichalcogenides (TMDs) introduces a valley-dependent effective magnetic field, which induces the valley Hall effect (VHE). Similar to the ordinary Hall effect, the VHE spatially separates carriers or excitons, depending on their valley index, and accumulates them at opposite sample edges. The VHE can play a key role in valleytronic devices, but previous observations of the VHE have been limited to cryogenic temperatures. Here, we report a demonstration of the VHE of interlayer excitons in a MoS2/WSe2 heterostructure at room temperature. We monitored the in-plane propagation of interlayer excitons through photoluminescence mapping and observed their spatial separation into two opposite transverse directions that depended on the valley index of the excitons. Our theoretical simulations reproduced the salient features of these observations. Our demonstration of the robust interlayer exciton VHE at room temperature, enabled by their intrinsically long lifetimes, will open up realistic possibilities for the development of opto-valleytronic devices based on TMD heterostructures.
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Affiliation(s)
- Zumeng Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 639798 Singapore
| | - Yuanda Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 639798 Singapore
| | - Kévin Dini
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 639798 Singapore
| | - Qinghai Tan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 639798 Singapore
| | - Zhuojun Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics , Sun Yat-sen University , Guangzhou 510275 , China
| | - Hanlin Fang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics , Sun Yat-sen University , Guangzhou 510275 , China
| | - Jin Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics , Sun Yat-sen University , Guangzhou 510275 , China
| | - Timothy Liew
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 639798 Singapore
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 639798 Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies , Nanyang Technological University , 639798 Singapore
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48
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Yu ZM, Guan S, Sheng XL, Gao W, Yang SA. Valley-Layer Coupling: A New Design Principle for Valleytronics. PHYSICAL REVIEW LETTERS 2020; 124:037701. [PMID: 32031831 DOI: 10.1103/physrevlett.124.037701] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Indexed: 06/10/2023]
Abstract
The current valleytronics research is based on the paradigm of time-reversal-connected valleys in two-dimensional (2D) hexagonal materials, which forbids the fully electric generation of valley polarization by a gate field. Here, we go beyond the existing paradigm to explore 2D systems with a novel valley-layer coupling (VLC) mechanism, where the electronic states in the emergent valleys have a valley-contrasted layer polarization. The VLC enables a direct coupling between a valley and a gate electric field. We analyze the symmetry requirements for a system to host VLC, demonstrate our idea via first-principles calculations and model analysis of a concrete 2D material example, and show that an electric, continuous, wide-range, and switchable control of valley polarization can be achieved by VLC. Furthermore, we find that systems with VLC can exhibit other interesting physics, such as valley-contrasting linear dichroism and optical selection of the valley and the electric polarization of interlayer excitons. Our finding opens a new direction for valleytronics and 2D materials research.
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Affiliation(s)
- Zhi-Ming Yu
- Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems, and School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Shan Guan
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xian-Lei Sheng
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
- Department of Physics, Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education), Beihang University, Beijing 100191, China
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
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49
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Wang J, Lin F, Verzhbitskiy I, Watanabe K, Taniguchi T, Martin J, Eda G. Polarity Tunable Trionic Electroluminescence in Monolayer WSe 2. NANO LETTERS 2019; 19:7470-7475. [PMID: 31517494 DOI: 10.1021/acs.nanolett.9b03215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Monolayer WSe2 exhibits luminescence arising from various types of exciton complexes due to strong many-body effects. Here, we demonstrate selective electrical excitation of positive and negative trions in van der Waals metal-insulator-semiconductor (MIS) heterostructure consisting of few-layer graphene (FLG), hexagonal boron nitride (hBN), and monolayer WSe2. Intentional unbalanced injection of electrons and holes is achieved via field-emission tunneling and electrostatic accumulation. The device exhibits planar electroluminescence from either positive trion X+ or negative trion X- depending on the bias conditions. We show that hBN serves as a tunneling barrier material allowing selective injection of electron or holes into WSe2 from FLG layer. Our observation offers prospects for hot carrier injection, trion manipulation, and on-chip excitonic devices based on two-dimensional semiconductors.
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Affiliation(s)
- Junyong Wang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Fanrong Lin
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Ivan Verzhbitskiy
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Kenji Watanabe
- National Institute for Material Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | - Takashi Taniguchi
- National Institute for Material Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | - Jens Martin
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Goki Eda
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543
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50
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Wei J, Zhao F, Liu J, Zhao Q, Wu N, Xu D. Enhanced exciton transport in an optical cavity field with spatially varying profile. Phys Rev E 2019; 100:012125. [PMID: 31499908 DOI: 10.1103/physreve.100.012125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Indexed: 11/07/2022]
Abstract
We explicitly consider the spatial profile of the light field in the study of exciton transport through a one-dimensional molecular aggregate in the cavity. When the scale of the aggregate is comparable with the cavity wavelength, the resultant exciton-photon coupling strength varies with the position of each monomer. Such effect is explicitly included in a quantum master equation describing the dynamics of the excitonic, photonic, and vibrational modes. By investigating the steady-state exciton currents, we show that the strong and spatially varying exciton-photon coupling dominates the exciton transport and significantly enhances the transport efficiency. With suitable intermonomer distance, the delocalized polaronic mode generates more occupation on the acceptor monomer than the bridge monomers and thus makes it a more efficient channel for exciton transfer. The effects of localized vibrations are also investigated, and the vibration-assisted exciton transport is demonstrated with strong exciton-vibration coupling. Our results show that the vibrational modes are not as significant as the spatially varying exciton-photon couplings in affecting the exciton transport.
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Affiliation(s)
- Jianye Wei
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Fang Zhao
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Jingyu Liu
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Qing Zhao
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Ning Wu
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing, People's Republic of China
| | - Dazhi Xu
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing, People's Republic of China
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