1
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Jung J, Choi H, Lee Y, Kim Y, Taniguchi T, Watanabe K, Choi M, Jang JH, Chung H, Kim D, Kim Y, Cho C. Defect Passivation of 2D Semiconductors by Fixating Chemisorbed Oxygen Molecules via h-BN Encapsulations. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2310197. [PMID: 38493313 PMCID: PMC11165525 DOI: 10.1002/advs.202310197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 02/25/2024] [Indexed: 03/18/2024]
Abstract
Hexagonal boron nitride (h-BN) is a key ingredient for various 2D van der Waals heterostructure devices, but the exact role of h-BN encapsulation in relation to the internal defects of 2D semiconductors remains unclear. Here, it is reported that h-BN encapsulation greatly removes the defect-related gap states by stabilizing the chemisorbed oxygen molecules onto the defects of monolayer WS2 crystals. Electron energy loss spectroscopy (EELS) combined with theoretical analysis clearly confirms that the oxygen molecules are chemisorbed onto the defects of WS2 crystals and are fixated by h-BN encapsulation, with excluding a possibility of oxygen molecules trapped in bubbles or wrinkles formed at the interface between WS2 and h-BN. Optical spectroscopic studies show that h-BN encapsulation prevents the desorption of oxygen molecules over various excitation and ambient conditions, resulting in a greatly lowered and stabilized free electron density in monolayer WS2 crystals. This suppresses the exciton annihilation processes by two orders of magnitude compared to that of bare WS2. Furthermore, the valley polarization becomes robust against the various excitation and ambient conditions in the h-BN encapsulated WS2 crystals.
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Affiliation(s)
- Jin‐Woo Jung
- Department of Physics and ChemistryDaegu Gyeongbuk Institute of Science and Technology (DGIST)Daegu42988South Korea
| | - Hyeon‐Seo Choi
- Department of Physics and ChemistryDaegu Gyeongbuk Institute of Science and Technology (DGIST)Daegu42988South Korea
| | - Young‐Jun Lee
- Department of Physics and ChemistryDaegu Gyeongbuk Institute of Science and Technology (DGIST)Daegu42988South Korea
| | - Youngjae Kim
- School of PhysicsKorea Institute for Advanced Study (KIAS)Seoul02455South Korea
| | - Takashi Taniguchi
- International Center for Materials NanoarchitectonicsNational Institute for Materials ScienceTsukuba305‐0044Japan
| | - Kenji Watanabe
- Research Center for Functional MaterialsNational Institute for Materials ScienceTsukuba305‐0044Japan
| | - Min‐Yeong Choi
- Electron Microscopy and Spectroscopy TeamKorea Basic Science InstituteDaejeon34133South Korea
| | - Jae Hyuck Jang
- Electron Microscopy and Spectroscopy TeamKorea Basic Science InstituteDaejeon34133South Korea
- Graduate School of Analytic Science and TechnologyChungnam National UniversityDaejeon34134South Korea
| | - Hee‐Suk Chung
- Electron Microscopy and Spectroscopy TeamKorea Basic Science InstituteDaejeon34133South Korea
| | - Dohun Kim
- Department of Physics and ChemistryDaegu Gyeongbuk Institute of Science and Technology (DGIST)Daegu42988South Korea
| | - Youngwook Kim
- Department of Physics and ChemistryDaegu Gyeongbuk Institute of Science and Technology (DGIST)Daegu42988South Korea
| | - Chang‐Hee Cho
- Department of Physics and ChemistryDaegu Gyeongbuk Institute of Science and Technology (DGIST)Daegu42988South Korea
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2
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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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3
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Feng S, Campbell AJ, Brotons-Gisbert M, Andres-Penares D, Baek H, Taniguchi T, Watanabe K, Urbaszek B, Gerber IC, Gerardot BD. Highly tunable ground and excited state excitonic dipoles in multilayer 2H-MoSe 2. Nat Commun 2024; 15:4377. [PMID: 38782967 DOI: 10.1038/s41467-024-48476-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 04/29/2024] [Indexed: 05/25/2024] Open
Abstract
The fundamental properties of an exciton are determined by the spin, valley, energy, and spatial wavefunctions of the Coulomb-bound electron and hole. In van der Waals materials, these attributes can be widely engineered through layer stacking configuration to create highly tunable interlayer excitons with static out-of-plane electric dipoles, at the expense of the strength of the oscillating in-plane dipole responsible for light-matter coupling. Here we show that interlayer excitons in bi- and tri-layer 2H-MoSe2 crystals exhibit electric-field-driven coupling with the ground (1s) and excited states (2s) of the intralayer A excitons. We demonstrate that the hybrid states of these distinct exciton species provide strong oscillator strength, large permanent dipoles (up to 0.73 ± 0.01 enm), high energy tunability (up to ~200 meV), and full control of the spin and valley characteristics such that the exciton g-factor can be manipulated over a large range (from -4 to +14). Further, we observe the bi- and tri-layer excited state (2s) interlayer excitons and their coupling with the intralayer excitons states (1s and 2s). Our results, in good agreement with a coupled oscillator model with spin (layer)-selectivity and beyond standard density functional theory calculations, promote multilayer 2H-MoSe2 as a highly tunable platform to explore exciton-exciton interactions with strong light-matter interactions.
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Affiliation(s)
- Shun Feng
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, UK
| | - Aidan J Campbell
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, UK
| | - Mauro Brotons-Gisbert
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, UK.
| | - Daniel Andres-Penares
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, UK
| | - Hyeonjun Baek
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, UK
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Bernhard Urbaszek
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Iann C Gerber
- INSA-CNRS-UPS LPCNO, Université de Toulouse, Toulouse, France
| | - Brian D Gerardot
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, UK.
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4
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Knorr W, Brem S, Meneghini G, Malic E. Polaron-induced changes in moiré exciton propagation in twisted van der Waals heterostructures. NANOSCALE 2024. [PMID: 38623653 DOI: 10.1039/d4nr00136b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Twisted transition metal dichalcogenides (TMDs) present an intriguing platform for exploring excitons and their transport properties. By introducing a twist angle, a moiré superlattice forms, providing a spatially dependent exciton energy landscape. Based on a microscopic many-particle theory, we investigate in this work polaron-induced changes in exciton transport properties in the exemplary MoSe2/WSe2 heterostructure. We demonstrate that polaron formation and the associated enhancement of the moiré exciton mass lead to a significant band flattening. As a result, the moiré inter-cell tunneling and the propagation velocity undergo noticeable temperature and twist-angle dependent changes. We predict a reduction of the hopping strength ranging from 80% at a twist angle of 1° to 30% at 3° at room temperature. The provided microscopic insights into the spatio-temporal exciton dynamics in presence of a moiré potential further expand the possibilities to tune charge and energy transport in 2D materials.
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Affiliation(s)
- Willy Knorr
- Department of Physics, Philipps University, 35037 Marburg, Germany.
| | - Samuel Brem
- Department of Physics, Philipps University, 35037 Marburg, Germany.
| | | | - Ermin Malic
- Department of Physics, Philipps University, 35037 Marburg, Germany.
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5
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Brinatti Vazquez GD, Lo Gerfo Morganti G, Vasilev C, Hunter CN, van Hulst NF. Structured Excitation Energy Transfer: Tracking Exciton Diffusion below Sunlight Intensity. ACS PHOTONICS 2024; 11:1318-1326. [PMID: 38523751 PMCID: PMC10958594 DOI: 10.1021/acsphotonics.4c00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/09/2024] [Accepted: 02/12/2024] [Indexed: 03/26/2024]
Abstract
With the increasing demand for new materials for light-harvesting applications, spatiotemporal microscopy techniques are receiving increasing attention as they allow direct observation of the nanoscale diffusion of excitons. However, the use of pulsed and tightly focused laser beams generates light intensities far above those expected under sunlight illumination, leading to photodamage and nonlinear effects that seriously limit the accuracy and applicability of these techniques, especially in biological or atomically thin materials. In this work, we present a novel spatiotemporal microscopy technique that exploits structured excitation in order to dramatically decrease the excitation intensity, up to 10,000-fold when compared with previously reported spatiotemporal photoluminescence microscopy experiments. We tested our method in two different systems, reporting the first exciton diffusion measurement at illumination conditions below sunlight, both considering average power and peak exciton densities in an organic photovoltaic sample (Y6), where we tracked the excitons for up to five recombination lifetimes. Next, nanometer-scale energy transport was directly observed for the first time in both space and time in a printed monolayer of the light-harvesting complex 2 from purple bacteria.
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Affiliation(s)
- Guillermo D. Brinatti Vazquez
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Giulia Lo Gerfo Morganti
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Cvetelin Vasilev
- School
of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K.
| | - C. Neil Hunter
- School
of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K.
| | - Niek F. van Hulst
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, Barcelona 08010, Spain
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6
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Gong Y, Yue S, Liang Y, Du W, Bian T, Jiang C, Bao X, Zhang S, Long M, Zhou G, Yin J, Deng S, Zhang Q, Wu B, Liu X. Boosting exciton mobility approaching Mott-Ioffe-Regel limit in Ruddlesden-Popper perovskites by anchoring the organic cation. Nat Commun 2024; 15:1893. [PMID: 38424438 PMCID: PMC10904778 DOI: 10.1038/s41467-024-45740-y] [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: 05/22/2022] [Accepted: 02/01/2024] [Indexed: 03/02/2024] Open
Abstract
Exciton transport in two-dimensional Ruddlesden-Popper perovskite plays a pivotal role for their optoelectronic performance. However, a clear photophysical picture of exciton transport is still lacking due to strong confinement effects and intricate exciton-phonon interactions in an organic-inorganic hybrid lattice. Herein, we present a systematical study on exciton transport in (BA)2(MA)n-1PbnI3n+1 Ruddlesden-Popper perovskites using time-resolved photoluminescence microscopy. We reveal that the free exciton mobilities in exfoliated thin flakes can be improved from around 8 cm2 V-1 s-1 to 280 cm2V-1s-1 by anchoring the soft butyl ammonium cation with a polymethyl methacrylate network at the surface. The mobility of the latter is close to the theoretical limit of Mott-Ioffe-Regel criterion. Combining optical measurements and theoretical studies, it is unveiled that the polymethyl methacrylate network significantly improve the lattice rigidity resulting in the decrease of deformation potential scattering and lattice fluctuation at the surface few layers. Our work elucidates the origin of high exciton mobility in Ruddlesden-Popper perovskites and opens up avenues to regulate exciton transport in two-dimensional materials.
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Affiliation(s)
- Yiyang Gong
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P.R. China
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Shuai Yue
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Yin Liang
- School of Materials Science and Engineering, Peking University, Beijing, 100871, P.R. China
| | - Wenna Du
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Tieyuan Bian
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P.R. China
| | - Chuanxiu Jiang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Xiaotian Bao
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China
| | - Shuai Zhang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Mingzhu Long
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P.R. China
| | - Guofu Zhou
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P.R. China
| | - Jun Yin
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P.R. China
| | - Shibin Deng
- Ultrafast Electron Microscopy Laboratory, School of Physics, Nankai University, Tianjin, 300071, P.R. China
- The MOE Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics, Nankai University, Tianjin, 300071, P.R. China
| | - Qing Zhang
- School of Materials Science and Engineering, Peking University, Beijing, 100871, P.R. China.
| | - Bo Wu
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P.R. China.
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China.
| | - Xinfeng Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, P.R. China.
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
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7
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Shcherbakov-Wu W, Saris S, Sheehan TJ, Wong NN, Powers ER, Krieg F, Kovalenko MV, Willard AP, Tisdale WA. Persistent enhancement of exciton diffusivity in CsPbBr 3 nanocrystal solids. SCIENCE ADVANCES 2024; 10:eadj2630. [PMID: 38381813 PMCID: PMC10881049 DOI: 10.1126/sciadv.adj2630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024]
Abstract
In semiconductors, exciton or charge carrier diffusivity is typically described as an inherent material property. Here, we show that the transport of excitons among CsPbBr3 perovskite nanocrystals (NCs) depends markedly on how recently those NCs were occupied by a previous exciton. Using transient photoluminescence microscopy, we observe a striking dependence of the apparent exciton diffusivity on excitation laser power that does not arise from nonlinear exciton-exciton interactions or thermal heating. We interpret our observations with a model in which excitons cause NCs to transition to a long-lived metastable configuration that markedly increases exciton transport. The exciton diffusivity observed here (>0.15 square centimeters per second) is considerably higher than that observed in other NC systems, revealing unusually strong excitonic coupling between NCs. The finding of a persistent enhancement in excitonic coupling may help explain other photophysical behaviors observed in CsPbBr3 NCs, such as superfluorescence, and inform the design of optoelectronic devices.
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Affiliation(s)
- Wenbi Shcherbakov-Wu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Seryio Saris
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Laboratory of Nanochemistry for Energy (LNCE), Institute of Chemical Sciences and Engineering (ISIC), École Polytechnique Fédérale de Lausanne, CH-1950 Sion, Switzerland
| | - Thomas John Sheehan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Narumi Nagaya Wong
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Eric R. Powers
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Franziska Krieg
- Department of Chemistry and Applied Bioscience, ETH Zürich, Zürich, Switzerland
- Laboratory for Thin Films and Photovoltaics and Laboratory for Transport at Nanoscale Interfaces, Empa – Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Maksym V. Kovalenko
- Department of Chemistry and Applied Bioscience, ETH Zürich, Zürich, Switzerland
- Laboratory for Thin Films and Photovoltaics and Laboratory for Transport at Nanoscale Interfaces, Empa – Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Adam P. Willard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - William A. Tisdale
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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8
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Bhattacharyya S, Sayer T, Montoya-Castillo A. Anomalous Transport of Small Polarons Arises from Transient Lattice Relaxation or Immovable Boundaries. J Phys Chem Lett 2024; 15:1382-1389. [PMID: 38288689 DOI: 10.1021/acs.jpclett.3c03380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Elucidating transport mechanisms is crucial for advancing material design, yet state-of-the-art theory is restricted to exact simulations of small lattices with severe finite-size effects or approximate ones that assume the nature of transport. We leverage algorithmic advances to tame finite-size effects and exactly simulate small polaron formation and transport in the Holstein model. We further analyze the applicability of the ubiquitously used equilibrium-based Green-Kubo relations and nonequilibrium methods to predict charge mobility. We find that these methods can converge to different values and track this disparity to finite-size dependence and the sensitivity of Green-Kubo relations to the system's topology. Contrary to standard perturbative calculations, our results demonstrate that small polarons exhibit anomalous transport that manifests transiently due to nonequilibrium lattice relaxation or permanently as a signature of immovable boundaries. These findings can offer new interpretations of transport experiments on polymers and transition metal oxides.
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Affiliation(s)
- Srijan Bhattacharyya
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Thomas Sayer
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Andrés Montoya-Castillo
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
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9
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Li B, Xu J, Kocoj CA, Li S, Li Y, Chen D, Zhang S, Dou L, Guo P. Dual-Hyperspectral Optical Pump-Probe Microscopy with Single-Nanosecond Time Resolution. J Am Chem Soc 2024; 146:2187-2195. [PMID: 38216555 DOI: 10.1021/jacs.3c12284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2024]
Abstract
In recent years, optical pump-probe microscopy (PPM) has become a vital technique for spatiotemporally imaging electronic excitations and charge-carrier transport in metals and semiconductors. However, existing methods are limited by mechanical delay lines with a probe time window up to several nanoseconds (ns) or monochromatic pump and probe sources with restricted spectral coverage and temporal resolution, hindering their amenability in studying relatively slow processes. To bridge these gaps, we introduce a dual-hyperspectral PPM setup with a time window spanning from nanoseconds to milliseconds and single-nanosecond resolution. Our method features a wide-field probe tunable from 370 to 1000 nm and a pump spanning from 330 nm to 16 μm. We apply this PPM technique to study various two-dimensional metal-halide perovskites (2D-MHPs) as representative semiconductors by imaging their transient responses near the exciton resonances under both above-band gap electronic pump excitation and below-band gap vibrational pump excitation. The resulting spatially and temporally resolved images reveal insights into heat dissipation, film uniformity, distribution of impurity phases, and film-substrate interfaces. In addition, the single-nanosecond temporal resolution enables the imaging of in-plane strain wave propagation in 2D-MHP single crystals. Our method, which offers extensive spectral tunability and significantly improved time resolution, opens new possibilities for the imaging of charge carriers, heat, and transient phase transformation processes, particularly in materials with spatially varying composition, strain, crystalline structure, and interfaces.
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Affiliation(s)
- Bowen Li
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Joy Xu
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Conrad A Kocoj
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Shunran Li
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Yanyan Li
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Du Chen
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Shuchen Zhang
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47906, United States
| | - Letian Dou
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47906, United States
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Peijun Guo
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
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10
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Gauriot N, Ashoka A, Lim J, See ST, Sung J, Rao A. Direct Imaging of Carrier Funneling in a Dielectric Engineered 2D Semiconductor. ACS NANO 2024; 18:264-271. [PMID: 38196169 PMCID: PMC10786151 DOI: 10.1021/acsnano.3c05957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/23/2023] [Accepted: 12/01/2023] [Indexed: 01/11/2024]
Abstract
In atomically thin transition-metal dichalcogenides (TMDCs), the environmental sensitivity of the strong Coulomb interaction offers promising approaches to create spatially varying potential landscapes in the same continuous material by tuning its dielectric environment. Thus, allowing for control of transport. However, a scalable and CMOS-compatible method for achieving this is required to harness these effects in practical applications. In addition, because of their ultrashort lifetime, observing the spatiotemporal dynamics of carriers in monolayer TMDCs, on the relevant time scale, is challenging. Here, we pattern and deposit a thin film of hafnium oxide (HfO2) via atomic layer deposition (ALD) on top of a monolayer of WSe2. This allows for the engineering of the dielectric environment of the monolayer and design of heterostructures with nanoscale spatial resolution via a highly scalable postsynthesis methodology. We then directly image the transport of photoexcitations in the monolayer with 50 fs time resolution and few-nanometer spatial precision, using a pump probe microscopy technique. We observe the unidirectional funneling of charge carriers, from the unpatterned to the patterned areas, over more than 50 nm in the first 20 ps with velocities of over 2 × 103 m/s at room temperature. These results demonstrate the possibilities offered by dielectric engineering via ALD patterning, allowing for arbitrary spatial patterns that define the potential landscape and allow for control of the transport of excitations in atomically thin materials. This work also shows the power of the transient absorption methodology to image the motion of photoexcited states in complex potential landscapes on ultrafast time scales.
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Affiliation(s)
- Nicolas Gauriot
- Cavendish
Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom
| | - Arjun Ashoka
- Cavendish
Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom
| | - Juhwan Lim
- Cavendish
Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom
| | - Soo Teck See
- Cavendish
Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom
| | - Jooyoung Sung
- Cavendish
Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom
- Department
of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
| | - Akshay Rao
- Cavendish
Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom
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11
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Wietek E, Florian M, Göser J, Taniguchi T, Watanabe K, Högele A, Glazov MM, Steinhoff A, Chernikov A. Nonlinear and Negative Effective Diffusivity of Interlayer Excitons in Moiré-Free Heterobilayers. PHYSICAL REVIEW LETTERS 2024; 132:016202. [PMID: 38242648 DOI: 10.1103/physrevlett.132.016202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/10/2023] [Indexed: 01/21/2024]
Abstract
Interlayer exciton diffusion is studied in atomically reconstructed MoSe_{2}/WSe_{2} heterobilayers with suppressed disorder. Local atomic registry is confirmed by characteristic optical absorption, circularly polarized photoluminescence, and g-factor measurements. Using transient microscopy we observe propagation properties of interlayer excitons that are independent from trapping at moiré- or disorder-induced local potentials. Confirmed by characteristic temperature dependence for free particles, linear diffusion coefficients of interlayer excitons at liquid helium temperature and low excitation densities are almost 1000 times higher than in previous observations. We further show that exciton-exciton repulsion and annihilation contribute nearly equally to nonlinear propagation by disentangling the two processes in the experiment and simulations. Finally, we demonstrate effective shrinking of the light emission area over time across several hundreds of picoseconds at the transition from exciton- to the plasma-dominated regimes. Supported by microscopic calculations for band gap renormalization to identify the Mott threshold, this indicates transient crossing between rapidly expanding, short-lived electron-hole plasma and slower, long-lived exciton populations.
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Affiliation(s)
- Edith Wietek
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Matthias Florian
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Jonas Göser
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München, Germany
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Alexander Högele
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München, Germany
- Munich Center for Quantum Science and Technology (MCQST), 80799 München, Germany
| | | | - Alexander Steinhoff
- Institut für Theoretische Physik, Universität Bremen, 28334 Bremen, Germany
- Bremen Center for Computational Materials Science, Universität Bremen, 28334 Bremen, Germany
| | - Alexey Chernikov
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
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12
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Kurilovich AA, Mantsevich VN, Chechkin AV, Palyulin VV. Negative diffusion of excitons in quasi-two-dimensional systems. Phys Chem Chem Phys 2024; 26:922-935. [PMID: 38088027 DOI: 10.1039/d3cp03521b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
We show how two different mobile-immobile type models explain the observation of negative diffusion of excitons reported in experimental studies in quasi-two-dimensional semiconductor systems. The main reason for the effect is the initial trapping and a delayed release of free excitons in the area close to the original excitation spot. The density of trapped excitons is not registered experimentally. Hence, the signal from the free excitons alone includes the delayed release of not diffusing trapped particles. This is seen as the narrowing of the exciton density profile or decrease of mean-squared displacement which is then interpreted as a negative diffusion. The effect is enhanced with the increase of recombination intensity as well as the rate of the exciton-exciton binary interactions.
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Affiliation(s)
- Aleksandr A Kurilovich
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, 121205, Moscow, Russia
| | - Vladimir N Mantsevich
- Chair of Semiconductors and Cryoelectronics, Physics department, Lomonosov Moscow State University, 119991, Moscow, Russia
| | - Aleksei V Chechkin
- Faculty of Pure and Applied Mathematics, Hugo Steinhaus Center, Wroclaw University of Science and Technology, Wyspianskiego 27, 50-370 Wroclaw, Poland
- Institute for Physics & Astronomy, University of Potsdam, D-14476 Potsdam-Golm, Germany
- Akhiezer Institute for Theoretical Physics National Science Center "Kharkov Institute of Physics and Technology", 61108, Kharkov, Ukraine
| | - Vladimir V Palyulin
- Applied AI centre, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Moscow, 121205, Russia.
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13
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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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14
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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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15
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Luo W, Lawrie BJ, Puretzky AA, Tan Q, Gao H, Lingerfelt DB, Eichman G, Mcgee E, Swan AK, Liang L, Ling X. Imaging Strain-Localized Single-Photon Emitters in Layered GaSe below the Diffraction Limit. ACS NANO 2023. [PMID: 38044592 DOI: 10.1021/acsnano.3c05250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Nanoscale strain control of exciton funneling is an increasingly critical tool for the scalable production of single photon emitters (SPEs) in two-dimensional materials. However, conventional far-field optical microscopies remain constrained in spatial resolution by the diffraction limit and thus can provide only a limited description of nanoscale strain localization of SPEs. Here, we quantify the effects of nanoscale heterogeneous strain on the energy and brightness of GaSe SPEs on nanopillars with correlative cathodoluminescence, photoluminescence, and atomic force microscopy, supported by density functional theory simulations. We report the strain-localized SPEs have a broad range of emission wavelengths from 620 to 900 nm. We reveal substantial strain-controlled SPE wavelength tunability over a ∼100 nm spectral range and 2 orders of magnitude enhancement in the SPE brightness at the pillar center due to Type-I exciton funneling. In addition, we show that radiative biexciton cascade processes contribute to observed CL photon superbunching. Also, the GaSe SPEs show excellent stability, where their properties remain unchanged after electron beam exposure. We anticipate that this comprehensive study on the nanoscale strain control of two-dimensional SPEs will provide key insights to guide the development of truly deterministic quantum photonics.
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Affiliation(s)
- Weijun Luo
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Benjamin J Lawrie
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Qishuo Tan
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Hongze Gao
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - David B Lingerfelt
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gage Eichman
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Edward Mcgee
- Department of Electrical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Anna K Swan
- Department of Electrical Engineering, Boston University, Boston, Massachusetts 02215, United States
- The Photonics Center, Boston University, Boston, Massachusetts 02215, United States
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Xi Ling
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
- The Photonics Center, Boston University, Boston, Massachusetts 02215, United States
- Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
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16
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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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17
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Tulyagankhodjaev JA, Shih P, Yu J, Russell JC, Chica DG, Reynoso ME, Su H, Stenor AC, Roy X, Berkelbach TC, Delor M. Room-temperature wavelike exciton transport in a van der Waals superatomic semiconductor. Science 2023; 382:438-442. [PMID: 37883547 DOI: 10.1126/science.adf2698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 09/21/2023] [Indexed: 10/28/2023]
Abstract
The transport of energy and information in semiconductors is limited by scattering between electronic carriers and lattice phonons, resulting in diffusive and lossy transport that curtails all semiconductor technologies. Using Re6Se8Cl2, a van der Waals (vdW) superatomic semiconductor, we demonstrate the formation of acoustic exciton-polarons, an electronic quasiparticle shielded from phonon scattering. We directly imaged polaron transport in Re6Se8Cl2 at room temperature, revealing quasi-ballistic, wavelike propagation sustained for a nanosecond and several micrometers. Shielded polaron transport leads to electronic energy propagation lengths orders of magnitude greater than in other vdW semiconductors, exceeding even silicon over a nanosecond. We propose that, counterintuitively, quasi-flat electronic bands and strong exciton-acoustic phonon coupling are together responsible for the transport properties of Re6Se8Cl2, establishing a path to ballistic room-temperature semiconductors.
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Affiliation(s)
| | - Petra Shih
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Jessica Yu
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Jake C Russell
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Daniel G Chica
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | | | - Haowen Su
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Athena C Stenor
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Xavier Roy
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | | | - Milan Delor
- Department of Chemistry, Columbia University, New York, NY 10027, USA
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18
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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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19
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Weaver H, Went CM, Wong J, Jasrasaria D, Rabani E, Atwater HA, Ginsberg NS. Detecting, Distinguishing, and Spatiotemporally Tracking Photogenerated Charge and Heat at the Nanoscale. ACS NANO 2023; 17:19011-19021. [PMID: 37721430 PMCID: PMC10569093 DOI: 10.1021/acsnano.3c04607] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
Since dissipative processes are ubiquitous in semiconductors, characterizing how electronic and thermal energy transduce and transport at the nanoscale is vital for understanding and leveraging their fundamental properties. For example, in low-dimensional transition metal dichalcogenides (TMDCs), excess heat generation upon photoexcitation is difficult to avoid since even with modest injected exciton densities exciton-exciton annihilation still occurs. Both heat and photoexcited electronic species imprint transient changes in the optical response of a semiconductor, yet the distinct signatures of each are difficult to disentangle in typical spectra due to overlapping resonances. In response, we employ stroboscopic optical scattering microscopy (stroboSCAT) to simultaneously map both heat and exciton populations in few-layer MoS2 on relevant nanometer and picosecond length- and time scales and with 100-mK temperature sensitivity. We discern excitonic contributions to the signal from heat by combining observations close to and far from exciton resonances, characterizing the photoinduced dynamics for each. Our approach is general and can be applied to any electronic material, including thermoelectrics, where heat and electronic observables spatially interplay, and it will enable direct and quantitative discernment of different types of coexisting energy without recourse to complex models or underlying assumptions.
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Affiliation(s)
- Hannah
L. Weaver
- Department
of Physics, University of California, Berkeley, California 94720, United States
| | - Cora M. Went
- Department
of Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Joeson Wong
- Department
of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Dipti Jasrasaria
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Eran Rabani
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- The
Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Harry A. Atwater
- Department
of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Naomi S. Ginsberg
- Department
of Physics, University of California, Berkeley, California 94720, United States
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Molecular
Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli
Energy NanoScience Institute, Berkeley, California 94720, United States
- STROBE
NSF Science & Technology Center, Berkeley, California 94720, United States
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20
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Magdaleno AJ, Cutler MM, Suurmond JJ, Meléndez M, Delgado-Buscalioni R, Seitz M, Prins F. Boosting the efficiency of transient photoluminescence microscopy using cylindrical lenses. NANOSCALE 2023; 15:14831-14836. [PMID: 37664969 DOI: 10.1039/d3nr03587e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Transient Photoluminescence Microscopy (TPLM) allows for the direct visualization of carrier transport in semiconductor materials with sub nanosecond and few nanometer resolution. The technique is based on measuring changes in the spatial distribution of a diffraction limited population of carriers using spatiotemporal detection of the radiative decay of the carriers. The spatial resolution of TPLM is therefore primarily determined by the signal-to-noise-ratio (SNR). Here we present a method using cylindrical lenses to boost the signal acquisition in TPLM experiments. The resulting asymmetric magnification of the photoluminescence emission of the diffraction limited spot can increase the collection efficiency by more than a factor of 10, significantly reducing acquisition times and further boosting spatial resolution.
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Affiliation(s)
- Alvaro J Magdaleno
- Condensed Matter Physics Center (IFIMAC) and Department of Condensed Matter Physics, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
| | - Mercy M Cutler
- Condensed Matter Physics Center (IFIMAC) and Department of Condensed Matter Physics, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
| | - Jesse J Suurmond
- Condensed Matter Physics Center (IFIMAC) and Department of Condensed Matter Physics, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
| | - Marc Meléndez
- Condensed Matter Physics Center (IFIMAC) and Department of Theoretical Condensed Matter Physics, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Rafael Delgado-Buscalioni
- Condensed Matter Physics Center (IFIMAC) and Department of Theoretical Condensed Matter Physics, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Michael Seitz
- Condensed Matter Physics Center (IFIMAC) and Department of Condensed Matter Physics, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
| | - Ferry Prins
- Condensed Matter Physics Center (IFIMAC) and Department of Condensed Matter Physics, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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21
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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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22
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Glazov MM. Excitons in atomically thin materials flow faster than they fly. NATURE NANOTECHNOLOGY 2023; 18:972-973. [PMID: 37524906 DOI: 10.1038/s41565-023-01448-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
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23
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Liu B, Lynch J, Zhao H, Conran BR, McAleese C, Jariwala D, Forrest SR. Long-Range Propagation of Exciton-Polaritons in Large-Area 2D Semiconductor Monolayers. ACS NANO 2023. [PMID: 37489978 DOI: 10.1021/acsnano.3c03485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Atomically thin transition metal dichalcogenides (TMDs), a subclass of two-dimensional (2D) layered materials, have numerous fascinating properties that make them a promising platform for photonic and optoelectronic devices. In particular, excited state transport by TMDs is important in energy harvesting and photonic switching; however, long-range transport in TMDs is challenging due to the lack of availability of large area films. Whereas most previous studies have focused on small, exfoliated monolayer flakes, in this work we demonstrate metal-organic chemical vapor deposition grown centimeter-scale monolayers of WS2 that support polariton propagation lengths of up to 60 μm. The polaritons form through the strong coupling of excitons with Bloch surface waves (BSWs) supported by all-dielectric photonic structures. We observe that the propagation length increases with the number of dielectric pairs due to the increased quality factor of the supporting distributed Bragg reflector. Furthermore, a longer propagation length is observed as the guided or BSW content of the polariton is increased. Our results provide a practical approach for the systematic engineering of long-range energy transport mediated by exciton-polaritons in TMD layers. Along with the accessibility of large area TMDs, our work enables applications for practical TMD-based polaritonic devices that operate at room temperature.
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Affiliation(s)
- Bin Liu
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jason Lynch
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Haonan Zhao
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Ben R Conran
- AIXTRON Ltd, Swavesey, Cambridge CB24 4FQ, United Kingdom
| | | | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Stephen R Forrest
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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24
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Erkensten D, Brem S, Perea-Causín R, Hagel J, Tagarelli F, Lopriore E, Kis A, Malic E. Electrically tunable dipolar interactions between layer-hybridized excitons. NANOSCALE 2023; 15:11064-11071. [PMID: 37309577 PMCID: PMC10324325 DOI: 10.1039/d3nr01049j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/02/2023] [Indexed: 06/14/2023]
Abstract
Transition-metal dichalcogenide bilayers exhibit a rich exciton landscape including layer-hybridized excitons, i.e. excitons which are of partly intra- and interlayer nature. In this work, we study hybrid exciton-exciton interactions in naturally stacked WSe2 homobilayers. In these materials, the exciton landscape is electrically tunable such that the low-energy states can be rendered more or less interlayer-like depending on the strength of the external electric field. Based on a microscopic and material-specific many-particle theory, we reveal two intriguing interaction regimes: a low-dipole regime at small electric fields and a high-dipole regime at larger fields, involving interactions between hybrid excitons with a substantially different intra- and interlayer composition in the two regimes. While the low-dipole regime is characterized by weak inter-excitonic interactions between intralayer-like excitons, the high-dipole regime involves mostly interlayer-like excitons which display a strong dipole-dipole repulsion and give rise to large spectral blue-shifts and a highly anomalous diffusion. Overall, our microscopic study sheds light on the remarkable electrical tunability of hybrid exciton-exciton interactions in atomically thin semiconductors and can guide future experimental studies in this growing field of research.
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Affiliation(s)
- Daniel Erkensten
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
| | - Samuel Brem
- Department of Physics, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Raül Perea-Causín
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
| | - Joakim Hagel
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
| | - Fedele Tagarelli
- Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Edoardo Lopriore
- Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Andras Kis
- Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, 35037 Marburg, Germany
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
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25
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Chen Y, Sun M. Plexcitonics: plasmon-exciton coupling for enhancing spectroscopy, optical chirality, and nonlinearity. NANOSCALE 2023. [PMID: 37377142 DOI: 10.1039/d3nr01388j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Plexcitonics is a rapidly developing interdisciplinary field that holds immense potential for the creation of innovative optical technologies and devices. This field focuses on investigating the interactions between plasmons and excitons in hybrid systems. In this review, we provide an overview of the fundamental principles of plasmonics and plexcitonics and discuss the latest advancements in plexcitonics. Specifically, we highlight the ability to manipulate plasmon-exciton interactions, the emerging field of tip-enhanced spectroscopy, and advancements in optical chirality and nonlinearity. These recent developments have spurred further research in the field of plexcitonics and offer inspiration for the design of advanced materials and devices with enhanced optical properties and functionalities.
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Affiliation(s)
- Yichuan Chen
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, P. R. China.
| | - Mengtao Sun
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, P. R. China.
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26
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Völzer T, Schubert A, von der Oelsnitz E, Schröer J, Barke I, Schwartz R, Watanabe K, Taniguchi T, Speller S, Korn T, Lochbrunner S. Strong quenching of dye fluorescence in monomeric perylene orange/TMDC hybrid structures. NANOSCALE ADVANCES 2023; 5:3348-3356. [PMID: 37325541 PMCID: PMC10263002 DOI: 10.1039/d3na00276d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023]
Abstract
Hybrid structures with an interface between two different materials with properly aligned energy levels facilitate photo-induced charge separation to be exploited in optoelectronic applications. Particularly, the combination of 2D transition metal dichalcogenides (TMDCs) and dye molecules offers strong light-matter interaction, tailorable band level alignments, and high fluorescence quantum yields. In this work, we aim at the charge or energy transfer-related quenching of the fluorescence of the dye perylene orange (PO) when isolated molecules are brought onto monolayer TMDCs via thermal vapor deposition. Here, micro-photoluminescence spectroscopy revealed a strong intensity drop of the PO fluorescence. For the TMDC emission, in contrast, we observed a relative growth of the trion versus exciton contribution. In addition, fluorescence imaging lifetime microscopy quantified the intensity quenching to a factor of about 103 and demonstrated a drastic lifetime reduction from 3 ns to values much shorter than the 100 ps width of the instrument response function. From the ratio of the intensity quenching that is attributed to hole or energy transfer from dye to semiconductor, we deduce a time constant of several picoseconds at most, pointing to an efficient charge separation suitable for optoelectronic devices.
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Affiliation(s)
- Tim Völzer
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
- Department "Life, Light and Matter", University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
| | - Alina Schubert
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
- Department "Life, Light and Matter", University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
| | - Erik von der Oelsnitz
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
- Department "Life, Light and Matter", University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
| | - Julian Schröer
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
- Department "Life, Light and Matter", University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
| | - Ingo Barke
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
- Department "Life, Light and Matter", University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
| | - Rico Schwartz
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan
| | - Sylvia Speller
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
- Department "Life, Light and Matter", University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
| | - Tobias Korn
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
- Department "Life, Light and Matter", University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
| | - Stefan Lochbrunner
- Institute of Physics, University of Rostock Albert-Einstein-Str. 23 18059 Rostock Germany
- Department "Life, Light and Matter", University of Rostock Albert-Einstein-Str. 25 18059 Rostock Germany
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27
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Malic E, Perea-Causin R, Rosati R, Erkensten D, Brem S. Exciton transport in atomically thin semiconductors. Nat Commun 2023; 14:3430. [PMID: 37301820 DOI: 10.1038/s41467-023-38556-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/09/2023] [Indexed: 06/12/2023] Open
Affiliation(s)
- Ermin Malic
- Department of Physics, Philipps-Universität Marburg, 35032, Marburg, Germany.
| | - Raül Perea-Causin
- Department of Physics, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Roberto Rosati
- Department of Physics, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Daniel Erkensten
- Department of Physics, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Samuel Brem
- Department of Physics, Philipps-Universität Marburg, 35032, Marburg, Germany
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28
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Choi J, Embley J, Blach DD, Perea-Causín R, Erkensten D, Kim DS, Yuan L, Yoon WY, Taniguchi T, Watanabe K, Ueno K, Tutuc E, Brem S, Malic E, Li X, Huang L. Fermi Pressure and Coulomb Repulsion Driven Rapid Hot Plasma Expansion in a van der Waals Heterostructure. NANO LETTERS 2023; 23:4399-4405. [PMID: 37154560 DOI: 10.1021/acs.nanolett.3c00678] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Transition metal dichalcogenide heterostructures provide a versatile platform to explore electronic and excitonic phases. As the excitation density exceeds the critical Mott density, interlayer excitons are ionized into an electron-hole plasma phase. The transport of the highly non-equilibrium plasma is relevant for high-power optoelectronic devices but has not been carefully investigated previously. Here, we employ spatially resolved pump-probe microscopy to investigate the spatial-temporal dynamics of interlayer excitons and hot-plasma phase in a MoSe2/WSe2 twisted bilayer. At the excitation density of ∼1014 cm-2, well exceeding the Mott density, we find a surprisingly rapid initial expansion of hot plasma to a few microns away from the excitation source within ∼0.2 ps. Microscopic theory reveals that this rapid expansion is mainly driven by Fermi pressure and Coulomb repulsion, while the hot carrier effect has only a minor effect in the plasma phase.
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Affiliation(s)
- Junho Choi
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jacob Embley
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Daria D Blach
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2050, United States
| | - Raül Perea-Causín
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Daniel Erkensten
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Dong Seob Kim
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Long Yuan
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2050, United States
| | - Woo Young Yoon
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Keiji Ueno
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Emanuel Tutuc
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Samuel Brem
- Department of Physics, Philipps University of Marburg, 35037 Marburg, Germany
| | - Ermin Malic
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
- Department of Physics, Philipps University of Marburg, 35037 Marburg, Germany
| | - Xiaoqin Li
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Libai Huang
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2050, United States
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29
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Kim D, Tran TT, Taniguchi T, Watanabe K, Kim J, Jang JI. Temperature Dependence of Excitonic Auger Recombination in Excitonic-Complex-Free Monolayer WS 2 by Considering Auger Broadening and Generation Efficiency. J Phys Chem Lett 2023; 14:4259-4265. [PMID: 37126643 DOI: 10.1021/acs.jpclett.3c00305] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Monolayer transition metal dichalcogenides (TMDs) have been extensively studied for their optoelectronic properties and applications. However, even at moderate exciton densities, their light-emitting capability is severely limited by Auger-type exciton-exciton annihilation (EEA). Previous work on EEA used oversimplified models in the presence of excitonic complexes, resulting in seriously underestimated values for the Auger coefficient. In this work, we transferred monolayer WS2 on a gold substrate with hBN encapsulation, where excitons persist as the main species at 3-300 K via metal proximity. We numerically solved the rate equation for excitons to accurately determine the Auger coefficient as a function of temperature by considering laser pulse width and spatially inhomogeneous exciton distribution. We found that the Auger coefficient consists of temperature-dependent and independent terms, consistent with a theoretical model for direct and exchange processes, respectively. We believe that our results provide a guide for enhancing the luminescence quantum yield of TMDs.
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Affiliation(s)
- Donggyu Kim
- Department of Physics, Sogang University, Seoul 04107, South Korea
| | - Trang Thu Tran
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Jeongyong Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Joon I Jang
- Department of Physics, Sogang University, Seoul 04107, South Korea
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30
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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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31
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López LEP, Rosławska A, Scheurer F, Berciaud S, Schull G. Tip-induced excitonic luminescence nanoscopy of an atomically resolved van der Waals heterostructure. NATURE MATERIALS 2023; 22:482-488. [PMID: 36928383 DOI: 10.1038/s41563-023-01494-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
The electronic and optical properties of van der Waals heterostructures are strongly influenced by the structuration and homogeneity of their nano- and atomic-scale environments. Unravelling this intimate structure-property relationship is a key challenge that requires methods capable of addressing the light-matter interactions in van der Waals materials with ultimate spatial resolution. Here we use a low-temperature scanning tunnelling microscope to probe-with atomic-scale resolution-the excitonic luminescence of a van der Waals heterostructure, made of a transition metal dichalcogenide monolayer stacked onto a few-layer graphene flake supported by a Au(111) substrate. Sharp emission lines arising from neutral, charged and localized excitons are reported. Their intensities and emission energies vary as a function of the nanoscale topography of the van der Waals heterostructure, explaining the variability of the emission properties observed with diffraction-limited approaches. Our work paves the way towards understanding and controlling optoelectronic phenomena in moiré superlattices with atomic-scale resolution.
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Affiliation(s)
- Luis E Parra López
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France
| | - Anna Rosławska
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France
| | - Fabrice Scheurer
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France
| | - Stéphane Berciaud
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France.
| | - Guillaume Schull
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France.
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Park S, Kim D, Choi YS, Baucour A, Kim D, Yoon S, Watanabe K, Taniguchi T, Shin J, Kim J, Seo MK. Customizing Radiative Decay Dynamics of Two-Dimensional Excitons via Position- and Polarization-Dependent Vacuum-Field Interference. NANO LETTERS 2023; 23:2158-2165. [PMID: 36854053 DOI: 10.1021/acs.nanolett.2c04604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Embodying bosonic and interactive characteristics in two-dimensional space, excitons in transition metal dichalcogenides (TMDCs) have garnered considerable attention. The utilization of the strong-correlation effects, long-range transport, and valley-dependent properties requires customizing exciton decay dynamics. Vacuum-field manipulation allows radiative decay engineering without disturbing intrinsic material properties. However, conventional flat mirrors cannot customize the radiative decay landscape in TMDC's plane or support vacuum-field interference with desired spectrum and polarization properties. Here, we present a meta-mirror platform resolving the issues with more optical degrees of freedom. For neutral excitons of the monolayer MoSe2, the optical layout formed by meta-mirrors manipulated the radiative decay rate in space by 2 orders of magnitude and revealed the statistical correlation between emission intensity and spectral line width. Moreover, the anisotropic meta-mirror demonstrated polarization-dependent radiative decay control. Our platform would be promising to tailor two-dimensional distributions of lifetime, density, diffusion, and polarization of TMDC excitons in advanced opto-excitonic applications.
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Affiliation(s)
- Sanghyeok Park
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Dongha Kim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Yun-Seok Choi
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Arthur Baucour
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Donghyeong Kim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Sangho Yoon
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Jonghwa Shin
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Jonghwan Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Center for van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Min-Kyo Seo
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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Lo Gerfo
M. G, Bolzonello L, Bernal-Texca F, Martorell J, van Hulst NF. Spatiotemporal Mapping Uncouples Exciton Diffusion from Singlet-Singlet Annihilation in the Electron Acceptor Y6. J Phys Chem Lett 2023; 14:1999-2005. [PMID: 36794828 PMCID: PMC9940293 DOI: 10.1021/acs.jpclett.2c03585] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/11/2023] [Indexed: 05/25/2023]
Abstract
Understanding the spatial dynamics of nanoscale exciton transport beyond the temporal decay is essential for further improvements of nanostructured optoelectronic devices, such as solar cells. The diffusion coefficient (D) of the nonfullerene electron acceptor Y6 has so far only been determined indirectly, from singlet-singlet annihilation (SSA) experiments. Here, we present the full picture of the exciton dynamics, adding the spatial domain to the temporal one, by spatiotemporally resolved photoluminescence microscopy. In this way, we directly track diffusion and we are able to decouple the real spatial broadening from its overestimation given by SSA. We measured the diffusion coefficient, D = 0.017 ± 0.003 cm2/s, which gives a Y6 film diffusion length of L=Dτ≈35 nm. Thus, we provide an essential tool that enables a direct and free-of-artifacts determination of diffusion coefficients, which we expect to be pivotal for further studies on exciton dynamics in energy materials.
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Affiliation(s)
- Giulia Lo Gerfo
M.
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
| | - Luca Bolzonello
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
| | - Francisco Bernal-Texca
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
| | - Jordi Martorell
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
- Departament
de Física, Universitat Politècnica
de Catalunya, Terrassa08222, Spain
| | - Niek F. van Hulst
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
- ICREA
- Institució Catalana de Recerca i Estudis Avançats, Barcelona08010, Spain
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34
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Nie X, Wu X, Wang Y, Ban S, Lei Z, Yi J, Liu Y, Liu Y. Surface acoustic wave induced phenomena in two-dimensional materials. NANOSCALE HORIZONS 2023; 8:158-175. [PMID: 36448884 DOI: 10.1039/d2nh00458e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Surface acoustic wave (SAW)-matter interaction provides a fascinating key for inducing and manipulating novel phenomena and functionalities in two-dimensional (2D) materials. The dynamic strain field and piezo-electric field associated with propagating SAWs determine the coherent manipulation and transduction between 2D excitons and phonons. Over the past decade, many intriguing acoustic-induced effects, including the acousto-electric effect, acousto-galvanic effect, acoustic Stark effect, acoustic Hall effect and acoustic exciton transport, have been reported experimentally. However, many more phenomena, such as the valley acousto-electric effect, valley acousto-electric Hall effect and acoustic spin Hall effect, were only theoretically proposed, the experimental verification of which are yet to be achieved. In this minireview, we attempt to overview the recent breakthrough of SAW-induced phenomena covering acoustic charge transport, acoustic exciton transport and modulation, and coherent acoustic phonons. Perspectives on the opportunities of the proposed SAW-induced phenomena, as well as open experimental challenges, are also discussed, attempting to offer some guidelines for experimentalists and theorists to explore the desired exotic properties and boost practical applications of 2D materials.
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Affiliation(s)
- Xuchen Nie
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Xiaoyue Wu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Yang Wang
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Siyuan Ban
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Zhihao Lei
- Global Innovative Centre for Advanced Nanomaterials, College of Engineering, Science and Environment, The University of Newcastle, NSW, 2308, Australia
| | - Jiabao Yi
- Global Innovative Centre for Advanced Nanomaterials, College of Engineering, Science and Environment, The University of Newcastle, NSW, 2308, Australia
| | - Ying Liu
- College of Jincheng, Nanjing University of Aeronautics and Astronautics, Nanjing 211156, China.
| | - Yanpeng Liu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
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35
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Nagaya Wong N, Ha SK, Williams K, Shcherbakov-Wu W, Swan JW, Tisdale WA. Robust estimation of charge carrier diffusivity using transient photoluminescence microscopy. J Chem Phys 2022; 157:104201. [DOI: 10.1063/5.0100075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transient microscopy has emerged as a powerful tool for imaging the diffusion of excitons and free charge carriers in optoelectronic materials. In many excitonic materials, extraction of diffusion coefficients can be simplified because of the linear relationship between signal intensity and local excited state population. However, in materials where transport is dominated by free charge carriers, extracting diffusivities accurately from multidimensional data is complicated by the nonlinear dependence of the measured signal on the local charge carrier density. To obtain accurate estimates of charge carrier diffusivity from transient microscopy data, statistically robust fitting algorithms coupled to efficient 3D numerical solvers that faithfully relate local carrier dynamics to raw experimental measurables are sometimes needed. Here, we provide a detailed numerical framework for modeling the spatiotemporal dynamics of free charge carriers in bulk semiconductors with significant solving speed reduction and for simulating the corresponding transient photoluminescence microscopy data. To demonstrate the utility of this approach, we apply a fitting algorithm using a Markov chain Monte Carlo sampler to experimental data on bulk CdS and methylammonium lead bromide (MAPbBr3) crystals. Parameter analyses reveal that transient photoluminescence microscopy can be used to obtain robust estimates of charge carrier diffusivities in optoelectronic materials of interest, but that other experimental approaches should be used for obtaining carrier recombination constants. Additionally, simplifications can be made to the fitting model depending on the experimental conditions and material systems studied. Our open-source simulation code and fitting algorithm are made freely available to the scientific community.
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Affiliation(s)
- Narumi Nagaya Wong
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Seung Kyun Ha
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Kristopher Williams
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Wenbi Shcherbakov-Wu
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - James W. Swan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - William A. Tisdale
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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36
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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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37
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Yu J, Han Y, Zhang H, Ding X, Qiao L, Hu J. Excimer Formation in the Non-Van-Der-Waals 2D Semiconductor Bi 2 O 2 Se. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2204227. [PMID: 35781340 DOI: 10.1002/adma.202204227] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/21/2022] [Indexed: 06/15/2023]
Abstract
The layered semiconductor Bi2 O2 Se is a promising new-type 2D material that holds layered structure via electrostatic forces instead of van der Waals (vdW) attractions. Aside from the huge success in device performance, the non-vdW nature in Bi2 O2 Se with a built-in interlayer electric field has also provided an appealing platform for investigating unique photoexcited carrier dynamics. Here, experimental evidence for the observation of excimers in multilayer Bi2 O2 Se nanosheets via transient absorption spectroscopy is presented. It is found that the excimer formation is the primary decay pathway of photoexcited excitons and three-stage excimer dynamics with corresponding time scales are established. Excitation-fluence-dependent excimer dynamics further suggest that the excimer is diffusive and its formation can be simply described as excitons relaxed to an excimer geometry. This work indicates the outstanding promise of unique excitonic processes in Bi2 O2 Se, which may motivate novel device designs.
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Affiliation(s)
- Junhong Yu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Yadong Han
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Hang Zhang
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Xiang Ding
- School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Liang Qiao
- School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Jianbo Hu
- Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, 621900, China
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, 621010, China
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38
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Yumoto G, Sekiguchi F, Hashimoto R, Nakamura T, Wakamiya A, Kanemitsu Y. Rapidly expanding spin-polarized exciton halo in a two-dimensional halide perovskite at room temperature. SCIENCE ADVANCES 2022; 8:eabp8135. [PMID: 35905182 PMCID: PMC9337763 DOI: 10.1126/sciadv.abp8135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Monitoring of the spatially resolved exciton spin dynamics in two-dimensional semiconductors has revealed the formation of a spatial pattern and long-range transport of the spin-polarized excitons, which holds promise for exciton-based spin-optoelectronic applications. However, the spatial evolution has been restricted to cryogenic temperatures because of the short exciton spin relaxation times at room temperature. Here, we report that two-dimensional halide perovskites can overcome this limitation owing to their relatively long exciton spin relaxation times and substantial exciton-exciton interactions. We demonstrate the emergence of a halo-like spatial profile in spin-polarized exciton population and its ultrafast expansion at room temperature by performing time-resolved Faraday rotation imaging of spin-polarized excitons in two-dimensional perovskite (C4H9NH3)2(CH3NH3)3Pb4I13. Exciton-exciton exchange interactions induce density-dependent nonlinear relaxation and ultrafast transport of exciton spins and give rise to a rapidly expanding halo-like spatial pattern. The density-dependent spatial control suggests the potential of using two-dimensional halide perovskites for spin-optoelectronic applications.
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39
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Katow H, Akashi R, Miyamoto Y, Tsuneyuki S. First-Principles Study of the Optical Dipole Trap for Two-Dimensional Excitons in Graphane. PHYSICAL REVIEW LETTERS 2022; 129:047401. [PMID: 35938993 DOI: 10.1103/physrevlett.129.047401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/31/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
Recent studies on excitons in two-dimensional materials have been widely conducted for their potential usages for novel electronic and optical devices. Especially, sophisticated manipulation techniques of quantum degrees of freedom of excitons are in demand. In this Letter we propose a technique of forming an optical dipole trap for excitons in graphane, a two-dimensional wide gap semiconductor, based on first-principles calculations. We develop a first-principles method to evaluate the transition dipole matrix between excitonic states and combine it with the density functional theory and GW+BSE calculations. We reveal that in graphane the huge exciton binding energy and the large dipole moments of Wannier-like excitons enable us to induce the dipole trap of the order of meV depth and μm width. This Letter opens a new way to control light-exciton interacting systems based on newly developed numerically robust ab initio calculations.
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Affiliation(s)
- Hiroki Katow
- Photon Science Center, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ryosuke Akashi
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yoshiyuki Miyamoto
- Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, Tsukuba, Ibaraki 305-8568, Japan
| | - Shinji Tsuneyuki
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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40
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Ren L, Lombez L, Robert C, Beret D, Lagarde D, Urbaszek B, Renucci P, Taniguchi T, Watanabe K, Crooker SA, Marie X. Optical Detection of Long Electron Spin Transport Lengths in a Monolayer Semiconductor. PHYSICAL REVIEW LETTERS 2022; 129:027402. [PMID: 35867459 DOI: 10.1103/physrevlett.129.027402] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Using a spatially resolved optical pump-probe experiment, we measure the lateral transport of spin-valley polarized electrons over very long distances (tens of micrometers) in a single WSe_{2} monolayer. By locally pumping the Fermi sea of 2D electrons to a high degree of spin-valley polarization (up to 75%) using circularly polarized light, the lateral diffusion of the electron polarization can be mapped out via the photoluminescence induced by a spatially separated and linearly polarized probe laser. Up to 25% spin-valley polarization is observed at pump-probe separations up to 20 μm. Characteristic spin-valley diffusion lengths of 18±3 μm are revealed at low temperatures. The dependence on temperature, pump helicity, pump intensity, and electron density highlight the key roles played by spin relaxation time and pumping efficiency on polarized electron transport in monolayer semiconductors possessing spin-valley locking.
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Affiliation(s)
- L Ren
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - L Lombez
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - C Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - D Beret
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - D Lagarde
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - B Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - P Renucci
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-00044, Japan
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-00044, Japan
| | - S A Crooker
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - X Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
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41
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Kurilovich AA, Mantsevich VN, Mardoukhi Y, Stevenson KJ, Chechkin AV, Palyulin VV. Non-Markovian diffusion of excitons in layered perovskites and transition metal dichalcogenides. Phys Chem Chem Phys 2022; 24:13941-13950. [PMID: 35621272 DOI: 10.1039/d2cp00557c] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The diffusion of excitons in perovskites and transition metal dichalcogenides shows clear anomalous, subdiffusive behaviour in experiments. In this paper we develop a non-Markovian mobile-immobile model which provides an explanation of this behaviour through paired theoretical and simulation approaches. The simulation model is based on a random walk on a 2D lattice with randomly distributed deep traps such that the trapping time distribution involves slowly decaying power-law asymptotics. The theoretical model uses coupled diffusion and rate equations for free and trapped excitons, respectively, with an integral term responsible for trapping. The model provides a good fitting of the experimental data, thus, showing a way for quantifying the exciton diffusion dynamics.
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Affiliation(s)
- Aleksandr A Kurilovich
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, 121205, Moscow, Russia
| | - Vladimir N Mantsevich
- Chair of Semiconductors and Cryoelectronics & Quantum Technology Center, Physics Department, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Yousof Mardoukhi
- Institute for Physics & Astronomy, University of Potsdam, D-14476 Potsdam-Golm, Germany
| | - Keith J Stevenson
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, 121205, Moscow, Russia
| | - Aleksei V Chechkin
- Institute for Physics & Astronomy, University of Potsdam, D-14476 Potsdam-Golm, Germany.,Faculty of Pure and Applied Mathematics, Hugo Steinhaus Center, Wroclaw University of Science and Technology, Wyspianskiego 27, 50-370 Wroclaw, Poland.,Akhiezer Institute for Theoretical Physics National Science Center "Kharkov Institute of Physics and Technology", 61108, Kharkov, Ukraine
| | - Vladimir V Palyulin
- RAIC Center, Skolkovo Institute of Science and Technology, 121205, Moscow, Russia.
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42
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Uddin SZ, Higashitarumizu N, Kim H, Yi J, Zhang X, Chrzan D, Javey A. Enhanced Neutral Exciton Diffusion in Monolayer WS 2 by Exciton-Exciton Annihilation. ACS NANO 2022; 16:8005-8011. [PMID: 35467828 DOI: 10.1021/acsnano.2c00956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dominant recombination pathways in monolayer transition metal dichalcogenides (TMDCs) depend primarily on background carrier concentration, generation rate, and applied strain. Charged excitons formed in the presence of background carriers mainly recombine nonradiatively. Neutral excitons recombine completely radiatively at low generation rates, but experience nonradiative exciton-exciton annihilation (EEA) at high generation rates. Strain can suppress EEA, resulting in near-unity photoluminescence quantum yield (PL QY) at all exciton densities. Although exciton diffusion is the primary channel of energy transport in excitonic materials and a critical optoelectronic design consideration, the combined effects of these factors on exciton diffusion are not clearly understood. In this work, we decouple the diffusion of neutral and charged excitons with chemical counterdoping and explore the effect of strain and generation rate on exciton diffusion. According to the standard semiconductor paradigm, a shorter carrier recombination lifetime should lead to a smaller diffusion length. Surprisingly, we find that increasing generation rate shortens the exciton lifetime but increases the diffusion length in unstrained monolayers of TMDCs. When we suppress EEA by strain, both lifetime and diffusion length become independent of generation rate. During EEA one exciton nonradiatively recombines and kinetically energizes another exciton, which then diffuses fast. Our results probe concentration-dependent diffusion of pure neutral excitons by counterdoping and elucidate how strain controls exciton transport and many-body interactions in TMDC monolayers.
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Affiliation(s)
- Shiekh Zia Uddin
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Naoki Higashitarumizu
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- 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 States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jun Yi
- NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, United States
| | - Xiang Zhang
- NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, United States
- Faculties of Sciences and Engineering, The University of Hong Kong, Hong Kong, China
| | - Daryl Chrzan
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Ali Javey
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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43
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Shimasaki M, Nishihara T, Matsuda K, Endo T, Takaguchi Y, Liu Z, Miyata Y, Miyauchi Y. Directional Exciton-Energy Transport in a Lateral Heteromonolayer of WSe 2-MoSe 2. ACS NANO 2022; 16:8205-8212. [PMID: 35481755 DOI: 10.1021/acsnano.2c01890] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Controlling the direction of exciton-energy flow in two-dimensional (2D) semiconductors is crucial for developing future high-speed optoelectronic devices using excitons as the information carriers. However, intrinsic exciton diffusion in conventional 2D semiconductors is omnidirectional, and efficient exciton-energy transport in a specific direction is difficult to achieve. Here we demonstrate directional exciton-energy transport across the interface in tungsten diselenide (WSe2)-molybdenum diselenide (MoSe2) lateral heterostructures. Unidirectional transport is spontaneously driven by the built-in asymmetry of the exciton-energy landscape with respect to the heterojunction interface. At excitation positions close to the interface, the exciton photoluminescence (PL) intensity was substantially decreased in the WSe2 region and enhanced in the MoSe2 region. In PL excitation spectroscopy, it was confirmed that the observed phenomenon arises from lateral exciton-energy transport from WSe2 to MoSe2. This directional exciton-energy flow in lateral 2D heterostructures can be exploited in future optoelectronic devices.
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Affiliation(s)
- Masafumi Shimasaki
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Taishi Nishihara
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kazunari Matsuda
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takahiko Endo
- Department of Physics, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachioji, Tokyo 192-0397, Japan
| | - Yuhei Takaguchi
- Department of Physics, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachioji, Tokyo 192-0397, Japan
| | - Zheng Liu
- Innovative Functional Materials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
| | - Yasumitsu Miyata
- Department of Physics, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachioji, Tokyo 192-0397, Japan
| | - Yuhei Miyauchi
- Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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44
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Chou HC, Zhang XQ, Shiau SY, Chien CH, Tang PW, Sung CT, Chang YC, Lee YH, Chen C. Near-field spectroscopic imaging of exciton quenching at atomically sharp MoS 2/WS 2 lateral heterojunctions. NANOSCALE 2022; 14:6323-6330. [PMID: 35297443 DOI: 10.1039/d2nr00216g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Heterojunctions made by laterally stitching two different transition metal dichalcogenide monolayers create a unique one-dimensional boundary with intriguing local optical properties that can only be characterized by nanoscale-spatial-resolution spectral tools. Here, we use near-field photoluminescence (NF-PL) to reveal the narrowest region (105 nm) ever reported of photoluminescence quenching at the junction of a laterally stitched WS2/MoS2 monolayer. We attribute this quenching to the atomically sharp band offset that generates a strong electric force at the junction to easily dissociate excitons. Besides the sharp heterojunction, a model considering various widths of the alloying interfacial region under low or high optical pumping is presented. With a spatial resolution six times better than that of confocal microscopy, NF-PL provides an unprecedented spectral tool for non-scalable 1D lateral heterojunctions.
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Affiliation(s)
- He-Chun Chou
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
| | - Xin-Quan Zhang
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, 300, Taiwan.
| | - Shiue-Yuan Shiau
- Physics Division, National Center for Theoretical Sciences, Taipei, 106, Taiwan
| | - Ching-Hang Chien
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
| | - Po-Wen Tang
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
| | - Chun-Te Sung
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, 300, Taiwan.
| | - Yia-Chung Chang
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
| | - Yi-Hsien Lee
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, 300, Taiwan.
| | - Chi Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
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45
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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: 11] [Impact Index Per Article: 5.5] [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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46
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Liu Q, Wei K, Tang Y, Xu Z, Cheng X, Jiang T. Visualizing Hot-Carrier Expansion and Cascaded Transport in WS 2 by Ultrafast Transient Absorption Microscopy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105746. [PMID: 35104054 PMCID: PMC8981895 DOI: 10.1002/advs.202105746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/04/2022] [Indexed: 06/14/2023]
Abstract
The competition between different spatiotemporal carrier relaxation determines the carrier harvesting in optoelectronic semiconductors, which can be greatly optimized by utilizing the ultrafast spatial expansion of highly energetic carriers before their energy dissipation via carrier-phonon interactions. Here, the excited-state dynamics in layered tungsten disulfide (WS2 ) are primarily imaged in the temporal, spatial, and spectral domains by transient absorption microscopy. Ultrafast hot carrier expansion is captured in the first 1.4 ps immediately after photoexcitation, with a mean diffusivity up to 980 cm2 s-1 . This carrier diffusivity then rapidly weakens, reaching a conventional linear spread of 10.5 cm2 s-1 after 2 ps after the hot carriers cool down to the band edge and form bound excitons. The novel carrier diffusion can be well characterized by a cascaded transport model including 3D thermal transport and thermo-optical conversion, in which the carrier temperature gradient and lattice thermal transport govern the initial hot carrier expansion and long-term exciton diffusion rates, respectively. The ultrafast hot carrier expansion breaks the limit of slow exciton diffusion in 2D transition metal dichalcogenides, providing potential guidance for high-performance applications and thermal management of optoelectronic technology.
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Affiliation(s)
- Qirui Liu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Ke Wei
- State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha, 410073, P. R. China
- Beijing Institute for Advanced Study, National University of Defense Technology, Beijing, 100000, P. R. China
| | - Yuxiang Tang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Zhongjie Xu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Xiang'ai Cheng
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Tian Jiang
- Beijing Institute for Advanced Study, National University of Defense Technology, Beijing, 100000, P. R. China
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47
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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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48
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Lee H, Koo Y, Choi J, Kumar S, Lee HT, Ji G, Choi SH, Kang M, Kim KK, Park HR, Choo H, Park KD. Drift-dominant exciton funneling and trion conversion in 2D semiconductors on the nanogap. SCIENCE ADVANCES 2022; 8:eabm5236. [PMID: 35119920 PMCID: PMC8816338 DOI: 10.1126/sciadv.abm5236] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/14/2021] [Indexed: 05/26/2023]
Abstract
Understanding and controlling the nanoscale transport of excitonic quasiparticles in atomically thin two-dimensional (2D) semiconductors are crucial to produce highly efficient nano-excitonic devices. Here, we present a nanogap device to selectively confine excitons or trions of 2D transition metal dichalcogenides at the nanoscale, facilitated by the drift-dominant exciton funneling into the strain-induced local spot. We investigate the spatiospectral characteristics of the funneled excitons in a WSe2 monolayer (ML) and converted trions in a MoS2 ML using hyperspectral tip-enhanced photoluminescence imaging with <15-nm spatial resolution. In addition, we dynamically control the exciton funneling and trion conversion rate by the gigapascal-scale tip pressure engineering. Through a drift-diffusion model, we confirm an exciton funneling efficiency of ∼25% with a significantly low strain threshold (∼0.1%), which sufficiently exceeds the efficiency of ∼3% in previous studies. This work provides a previously unexplored strategy to facilitate efficient exciton transport and trion conversion of 2D semiconductor devices.
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Affiliation(s)
- Hyeongwoo Lee
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Yeonjeong Koo
- 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
| | - Shailabh Kumar
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA 91125, USA
| | - Hyoung-Taek Lee
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Gangseon Ji
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Soo Ho Choi
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
| | - Mingu Kang
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - 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
| | - Hyeong-Ryeol Park
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Hyuck Choo
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA 91125, USA
- Imaging Device Lab, Device and System Research Center, Samsung Advanced Institute of Technology (SAIT), Suwon 16678, 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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49
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Uddin SZ, Higashitarumizu N, Kim H, Rabani E, Javey A. Engineering Exciton Recombination Pathways in Bilayer WSe 2 for Bright Luminescence. ACS NANO 2022; 16:1339-1345. [PMID: 35014783 DOI: 10.1021/acsnano.1c09255] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Exciton-exciton annihilation (EEA) in counterdoped monolayer transition metal dichalcogenides (TMDCs) can be suppressed by favorably changing the band structure with strain. The photoluminescence (PL) quantum yield (QY) monotonically approaches unity with strain at all generation rates. In contrast, here in bilayers (2L) of tungsten diselenide (WSe2) we observe a nonmonotonic change in EEA rate at high generation rates accompanied by a drastic enhancement in their PL QY at low generation rates. EEA is suppressed at both 0% and 1% strain, but activated at intermediate strains. We explain our observation through the indirect to direct transition in 2L WSe2 under uniaxial tensile strain. By strain and electrostatic counterdoping, we attain ∼50% PL QY at all generation rates in 2L WSe2, originally an indirect semiconductor. We demonstrate transient electroluminescence from 2L WSe2 with ∼1.5% internal quantum efficiency for a broad range of carrier densities by applying strain, which is ∼50 times higher than without strain. The present results elucidate the complete optoelectronic photophysics where indirect and direct excitons are simultaneously present and expedite exciton engineering in a TMDC multilayer beyond indirect-direct bandgap transition.
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Affiliation(s)
- Shiekh Zia Uddin
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Naoki Higashitarumizu
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- 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 States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Eran Rabani
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- The Raymond and Beverly Sackler Center of Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ali Javey
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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50
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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: 25] [Impact Index Per Article: 12.5] [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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