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Emelianov AV, Pettersson M, Bobrinetskiy II. Ultrafast Laser Processing of 2D Materials: Novel Routes to Advanced Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2402907. [PMID: 38757602 DOI: 10.1002/adma.202402907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/23/2024] [Indexed: 05/18/2024]
Abstract
Ultrafast laser processing has emerged as a versatile technique for modifying materials and introducing novel functionalities. Over the past decade, this method has demonstrated remarkable advantages in the manipulation of 2D layered materials, including synthesis, structuring, functionalization, and local patterning. Unlike continuous-wave and long-pulsed optical methods, ultrafast lasers offer a solution for thermal heating issues. Nonlinear interactions between ultrafast laser pulses and the atomic lattice of 2D materials substantially influence their chemical and physical properties. This paper highlights the transformative role of ultrafast laser pulses in maskless green technology, enabling subtractive, and additive processes that unveil ways for advanced devices. Utilizing the synergetic effect between the energy states within the atomic layers and ultrafast laser irradiation, it is feasible to achieve unprecedented resolutions down to several nanometers. Recent advancements are discussed in functionalization, doping, atomic reconstruction, phase transformation, and 2D and 3D micro- and nanopatterning. A forward-looking perspective on a wide array of applications of 2D materials, along with device fabrication featuring novel physical and chemical properties through direct ultrafast laser writing, is also provided.
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Affiliation(s)
- Aleksei V Emelianov
- Nanoscience Center, Department of Chemistry, University of Jyväskylä, Jyväskylä, FI-40014, Finland
| | - Mika Pettersson
- Nanoscience Center, Department of Chemistry, University of Jyväskylä, Jyväskylä, FI-40014, Finland
| | - Ivan I Bobrinetskiy
- BioSense Institute - Research and Development Institute for Information Technologies in Biosystems, University of Novi Sad, Novi Sad, 21000, Serbia
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2
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Li Z, Chen Z, Xiao L, Zhou X, Zhao C, Zhang Y. Extremely Enhanced Photoluminescence in MoS 2-Derived Quantum Sheets. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38470979 DOI: 10.1021/acsami.3c17934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Molybdenum disulfide (MoS2) quantum sheets (QSs) are attractive for applications due to their tunable energy band structures and optical and electronic properties. The photoluminescence quantum yield (PLQY) of MoS2 QSs achieved by mechanical and liquid exfoliation and chemical vapor deposition is low. Some studies have reported that chemical treatment and elemental doping can improve the PLQY of transition metal dichalcogenides (TMDs), but this is limited by complex instruments and reactions. In this study, a heat treatment method based on a polar solvent is reported to improve the PLQY and photoluminescence (PL) intensity of MoS2 QSs at room temperature. The absolute PLQY of treated MoS2 QSs is increased to 18.5%, and the PL intensity is increased by a factor of 64. This method is also effective for tungsten disulfide (WS2) QSs. The PL enhancement of QSs is attributed to oxidation of the edges. Such passivation/deformation of MoS2 QSs facilitates the radiative route rather than the nonradiative route, resulting in extreme enhancement of the PL. Our work could provide novel insights/routes toward the PL enhancement of TMD QSs.
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Affiliation(s)
- Zhangqiang Li
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Zhexue Chen
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Liuyang Xiao
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xuanping Zhou
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Ce Zhao
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Yong Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, 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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3
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Tang J, Li Y, Ye S, Jiang P, Xue Z, Li X, Lyu X, Liu Q, Chu S, Yang H, Wu C, Hu X, Gao Y, Wang S, Sun Q, Lu G, Gong Q. Direct Hot-Electron Transfer at the Au Nanoparticle/Monolayer Transition-Metal Dichalcogenide Interface Observed with Ultrahigh Spatiotemporal Resolution. NANO LETTERS 2024; 24:2931-2938. [PMID: 38377049 DOI: 10.1021/acs.nanolett.4c00324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Plasmon-induced hot-electron transfer at the metallic nanoparticle/semiconductor interface is the basis of plasmon-enhanced photocatalysis and energy harvesting. However, limited by the nanoscale size of hot spots and femtosecond time scale of hot-electron transfer, direct observation is still challenging. Herein, by using spatiotemporal-resolved photoemission electron microscopy with a two-color pump-probe beamline, we directly observed such a process with a concise system, the Au nanoparticle/monolayer transition-metal dichalcogenide (TMD) interface. The ultrafast hot-electron transfer from Au nanoparticles to monolayer TMDs and the plasmon-enhanced transfer process were directly measured and verified through an in situ comparison with the Au film/TMD interface and free TMDs. The lifetime at the Au nanoparticle/MoSe2 interface decreased from 410 to 42 fs, while the photoemission intensities exhibited a 27-fold increase compared to free MoSe2. We also measured the evolution of hot electrons in the energy distributions, indicating the hot-electron injection and decay happened in an ultrafast time scale of ∼50 fs without observable electron cooling.
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Affiliation(s)
- Jinglin Tang
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Yaolong Li
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Sheng Ye
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Pengzuo Jiang
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Zhaohang Xue
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Xiaofang Li
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Xiaying Lyu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Qinyun Liu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Saisai Chu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
| | - Hong Yang
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Chengyin Wu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Xiaoyong Hu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yunan Gao
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Shufeng Wang
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Quan Sun
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
| | - Guowei Lu
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics & Department of Physics, Collaborative Innovation Center of Quantum Matter and Frontiers Science Center for Nano-optoelectronics, Beijing Academy of Quantum Information Sciences, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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4
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Lu H, Long R. Nonadiabatic Molecular Dynamics with Non-Condon Effect of Charge Carrier Dynamics. J Am Chem Soc 2024; 146:1167-1173. [PMID: 38127733 DOI: 10.1021/jacs.3c12687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Nonradiative multiphonon transitions play a crucial role in understanding charge carrier dynamics. To capture the non-Condon effect in nonadiabatic molecular dynamics (NA-MD), we develop a simple and accurate method to calculate noncrossing and crossing k-point NA coupling in momentum space on an equal footing and implement it with a trajectory surface hopping algorithm. Multiple k-point MD trajectories can provide sufficient nonzero momentum multiphonons coupled to electrons, and the momentum conservation is maintained during nonvertical electron transition. The simulations of indirect bandgap transition in silicon and intra- and intervalley transitions in graphene show that incorporation of the non-Condon effect is needed to correctly depict these types of charge dynamics. In particular, a hidden process is responsible for the delayed nonradiative electron-hole recombination in silicon: the thermal-assisted rapid trapping of an excited electron at the conduction band minimum by a long-lived higher energy state through a nonvertical transition extends charge carrier lifetime, approaching 1 ns, which is about 1.5 times slower than the direct bandgap recombination. For graphene, intervalley scattering takes place within about 225 fs, which can occur only when the intravalley relaxation proceeds to about 50 fs to gain enough phonon momentum. The intra- and intervalley scattering constitute energy relaxation, which completes within sub-500 fs. All the simulated time scales are in excellent agreement with experiments. The study establishes the underlying mechanisms for a long-lived charge carrier in silicon and valley scattering in graphene and underscores the robustness of the non-Condon approximation NA-MD method, which is suitable for rigid, soft, and large defective systems.
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Affiliation(s)
- Haoran Lu
- College of Chemistry and Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Run Long
- College of Chemistry and Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, People's Republic of China
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5
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Picker J, Schaal M, Gan Z, Gruenewald M, Neumann C, George A, Otto F, Forker R, Fritz T, Turchanin A. Structural and electronic properties of MoS 2 and MoSe 2 monolayers grown by chemical vapor deposition on Au(111). NANOSCALE ADVANCES 2023; 6:92-101. [PMID: 38125607 PMCID: PMC10729873 DOI: 10.1039/d3na00475a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/24/2023] [Indexed: 12/23/2023]
Abstract
The exceptional electronic and photonic properties of the monolayers of transition metal dichalcogenides including the spin-orbit splitting of the valence and conduction bands at the K points of the Brillouin zone make them promising for novel applications in electronics, photonics and optoelectronics. Scalable growth of these materials and understanding of their interaction with the substrate is crucial for these applications. Here we report the growth of MoS2 and MoSe2 monolayers on Au(111) by chemical vapor deposition at ambient pressure as well as the analysis of their structural and electronic properties down to the atomic scale. To this aim, we apply ultrahigh vacuum surface sensitive techniques including scanning tunneling microscopy and spectroscopy, low-energy electron diffraction, X-ray and angle-resolved ultraviolet photoelectron spectroscopy in combination with Raman spectroscopy at ambient conditions. We demonstrate the growth of high-quality epitaxial single crystalline MoS2 and MoSe2 monolayers on Au(111) and show the impact of annealing on the monolayer/substrate interaction. Thus, as-grown and moderately annealed (<100 °C) MoSe2 monolayers are decoupled from the substrate by excess Se atoms, whereas annealing at higher temperatures (>250 °C) results in their strong coupling with the substrate caused by desorption of the excess Se. The MoS2 monolayers are strongly coupled to the substrate and the interaction remains almost unchanged even after annealing up to 450 °C.
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Affiliation(s)
- Julian Picker
- Institute of Physical Chemistry, Friedrich Schiller University Jena Lessingstraße 10 07743 Jena Germany
| | - Maximilian Schaal
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Ziyang Gan
- Institute of Physical Chemistry, Friedrich Schiller University Jena Lessingstraße 10 07743 Jena Germany
| | - Marco Gruenewald
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Christof Neumann
- Institute of Physical Chemistry, Friedrich Schiller University Jena Lessingstraße 10 07743 Jena Germany
| | - Antony George
- Institute of Physical Chemistry, Friedrich Schiller University Jena Lessingstraße 10 07743 Jena Germany
| | - Felix Otto
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Roman Forker
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Torsten Fritz
- Institute of Solid State Physics, Friedrich Schiller University Jena Helmholtzweg 5 07743 Jena Germany
| | - Andrey Turchanin
- Institute of Physical Chemistry, Friedrich Schiller University Jena Lessingstraße 10 07743 Jena Germany
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6
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Maingot B, Neradovskaia E, Claudet C, Forget N, Jullien A. Measurement of nonlinear refractive indices of bulk and liquid crystals by nonlinear chirped interferometry. OPTICS LETTERS 2023; 48:3243-3246. [PMID: 37319072 DOI: 10.1364/ol.487261] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/08/2023] [Indexed: 06/17/2023]
Abstract
The nonlinear refractive indices (n2) of a selection of bulk (LiB3O5, KTiOAsO4, MgO:LiNbO3, LiGaS2, ZnSe) and liquid (E7, MLC2132) crystals are measured at 1030 nm in the sub-picosecond regime (200 fs) by nonlinear chirped interferometry. The reported values provide key parameters for the design of near- to mid-infrared parametric sources, as well as all-optical delay lines.
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7
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Austin R, Farah Y, Sayer T, Luther B, Montoya-Castillo A, Krummel A, Sambur J. Hot carrier extraction from 2D semiconductor photoelectrodes. Proc Natl Acad Sci U S A 2023; 120:e2220333120. [PMID: 37011201 PMCID: PMC10104502 DOI: 10.1073/pnas.2220333120] [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: 11/29/2022] [Accepted: 03/07/2023] [Indexed: 04/05/2023] Open
Abstract
Hot carrier-based energy conversion systems could double the efficiency of conventional solar energy technology or drive photochemical reactions that would not be possible using fully thermalized, "cool" carriers, but current strategies require expensive multijunction architectures. Using an unprecedented combination of photoelectrochemical and in situ transient absorption spectroscopy measurements, we demonstrate ultrafast (<50 fs) hot exciton and free carrier extraction under applied bias in a proof-of-concept photoelectrochemical solar cell made from earth-abundant and potentially inexpensive monolayer (ML) MoS2. Our approach facilitates ultrathin 7 Å charge transport distances over 1 cm2 areas by intimately coupling ML-MoS2 to an electron-selective solid contact and a hole-selective electrolyte contact. Our theoretical investigations of the spatial distribution of exciton states suggest greater electronic coupling between hot exciton states located on peripheral S atoms and neighboring contacts likely facilitates ultrafast charge transfer. Our work delineates future two-dimensional (2D) semiconductor design strategies for practical implementation in ultrathin photovoltaic and solar fuel applications.
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Affiliation(s)
- Rachelle Austin
- Department of Chemistry, Colorado State University, Fort Collins, CO80523
| | - Yusef R. Farah
- Department of Chemistry, Colorado State University, Fort Collins, CO80523
| | - Thomas Sayer
- Department of Chemistry, University of Colorado Boulder, Boulder, CO80309
| | - Bradley M. Luther
- Department of Chemistry, Colorado State University, Fort Collins, CO80523
| | | | - Amber T. Krummel
- Department of Chemistry, Colorado State University, Fort Collins, CO80523
| | - Justin B. Sambur
- Department of Chemistry, Colorado State University, Fort Collins, CO80523
- School of Advanced Materials Discovery, Colorado State University, Fort Collins, CO80523
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Pincelli T, Vasileiadis T, Dong S, Beaulieu S, Dendzik M, Zahn D, Lee SE, Seiler H, Qi Y, Xian RP, Maklar J, Coy E, Mueller NS, Okamura Y, Reich S, Wolf M, Rettig L, Ernstorfer R. Observation of Multi-Directional Energy Transfer in a Hybrid Plasmonic-Excitonic Nanostructure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209100. [PMID: 36482148 DOI: 10.1002/adma.202209100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/29/2022] [Indexed: 06/17/2023]
Abstract
Hybrid plasmonic devices involve a nanostructured metal supporting localized surface plasmons to amplify light-matter interaction, and a non-plasmonic material to functionalize charge excitations. Application-relevant epitaxial heterostructures, however, give rise to ballistic ultrafast dynamics that challenge the conventional semiclassical understanding of unidirectional nanometal-to-substrate energy transfer. Epitaxial Au nanoislands are studied on WSe2 with time- and angle-resolved photoemission spectroscopy and femtosecond electron diffraction: this combination of techniques resolves material, energy, and momentum of charge-carriers and phonons excited in the heterostructure. A strong non-linear plasmon-exciton interaction that transfers the energy of sub-bandgap photons very efficiently to the semiconductor is observed, leaving the metal cold until non-radiative exciton recombination heats the nanoparticles on hundreds of femtoseconds timescales. The results resolve a multi-directional energy exchange on timescales shorter than the electronic thermalization of the nanometal. Electron-phonon coupling and diffusive charge-transfer determine the subsequent energy flow. This complex dynamics opens perspectives for optoelectronic and photocatalytic applications, while providing a constraining experimental testbed for state-of-the-art modelling.
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Affiliation(s)
- Tommaso Pincelli
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Thomas Vasileiadis
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznanskiego 2, Poznan, 61-614, Poland
| | - Shuo Dong
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Samuel Beaulieu
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Université de Bordeaux - CNRS - CEA, CELIA, UMR5107, Talence, F33405, France
| | - Maciej Dendzik
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, Stockholm, 114 19, Sweden
| | - Daniela Zahn
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Sang-Eun Lee
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Hélène Seiler
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Yingpeng Qi
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Center for Ultrafast Science and Technology, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - R Patrick Xian
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Department of Statistical Sciences, University of Toronto, 700 University Avenue, Toronto, M5G 1Z5, Canada
| | - Julian Maklar
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Emerson Coy
- NanoBioMedical Centre, Adam Mickiewicz University, ul. Wszechnicy Piastowskiej 3, Poznań, PL 61614, Poland
| | - Niclas S Mueller
- Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge, CB30HE, UK
| | - Yu Okamura
- Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Stephanie Reich
- Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Martin Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Laurenz Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Ralph Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
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9
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Kunin A, Chernov S, Bakalis J, Li Z, Cheng S, Withers ZH, White MG, Schönhense G, Du X, Kawakami RK, Allison TK. Momentum-Resolved Exciton Coupling and Valley Polarization Dynamics in Monolayer WS_{2}. PHYSICAL REVIEW LETTERS 2023; 130:046202. [PMID: 36763432 DOI: 10.1103/physrevlett.130.046202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
Using time- and angle-resolved photoemission, we present momentum- and energy-resolved measurements of exciton coupling in monolayer WS_{2}. We observe strong intravalley coupling between the B_{1s} exciton and A_{n>1} states. Our measurements indicate that the dominant valley depolarization mechanism conserves the exciton binding energy and momentum. While this conservation is consistent with Coulomb exchange-driven valley depolarization, we do not observe a momentum or energy dependence to the depolarization rate as would be expected for the exchange-based mechanism.
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Affiliation(s)
- Alice Kunin
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA
| | - Sergey Chernov
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA
| | - Jin Bakalis
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA
| | - Ziling Li
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Shuyu Cheng
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Zachary H Withers
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
| | - Michael G White
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Gerd Schönhense
- Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
| | - Xu Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
| | - Roland K Kawakami
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Thomas K Allison
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
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10
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Liu F. Time- and angle-resolved photoemission spectroscopy (TR-ARPES) of TMDC monolayers and bilayers. Chem Sci 2023; 14:736-750. [PMID: 36755720 PMCID: PMC9890651 DOI: 10.1039/d2sc04124c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 12/04/2022] [Indexed: 12/12/2022] Open
Abstract
Many unique properties in two-dimensional (2D) materials and their heterostructures rely on charge excitation, scattering, transfer, and relaxation dynamics across different points in the momentum space. Understanding these dynamics is crucial in both the fundamental study of 2D physics and their incorporation in optoelectronic and quantum devices. A direct method to probe charge carrier dynamics with momentum resolution is time- and angle-resolved photoemission spectroscopy (TR-ARPES). Such measurements have been challenging, since photoexcited carriers in many 2D monolayers reside at high crystal momenta, requiring probe photon energies in the extreme UV (EUV) regime. These challenges have been recently addressed by development of table-top pulsed EUV sources based on high harmonic generation, and the successful integration into a TR-ARPES and/or time-resolved momentum microscope. Such experiments will allow direct imaging of photoelectrons with superior time, energy, and crystal momentum resolution, with unique advantage over traditional optical measurements. Recently, TR-ARPES experiments of 2D transition metal dichalcogenide (TMDC) monolayers and bilayers have created unprecedented opportunities to reveal many intrinsic dynamics of 2D materials, such as bandgap renormalization, charge carrier scattering, relaxation, and wavefunction localization in moiré patterns. This perspective aims to give a short review of recent discoveries and discuss the challenges and opportunities of such techniques in the future.
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Affiliation(s)
- Fang Liu
- Department of Chemistry and the PULSE Institute, Stanford University Stanford California 94305 USA
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11
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Shang H, Hu Y, Gao F, Dai M, Zhang S, Wang S, Ouyang D, Li X, Song X, Gao B, Zhai T, Hu P. Carrier Recirculation Induced High-Gain Photodetector Based on van der Waals Heterojunction. ACS NANO 2022; 16:21293-21302. [PMID: 36468786 DOI: 10.1021/acsnano.2c09366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional (2D) materials have attracted great attention in the field of photodetection due to their excellent electronic and optoelectronic properties. However, the weak optical absorption caused by atomically thin layers and the short lifetime of photocarriers limit their optoelectronic performance, especially for weak light detection. In this work, we design a high-gain photodetector induced by carrier recirculation based on a vertical InSe/GaSe heterojunction. In this architecture, the photogenerated holes are trapped in GaSe due to the built-in electric field, suppressing the recombination rate of photocarriers, so the electrons can recirculate for multiple times in the InSe channel following the generation of a single electron-hole pair, resulting a high photoconductive gain (107). The responsivity and detectivity of the InSe/GaSe heterojunction can reach 1037 A/W and 8.6 × 1013 Jones, which are 1 order of magnitude higher than those of individual InSe. More importantly, the InSe/GaSe heterojunction can respond to weaker light (1 μW/cm2) compared to individual InSe (10 μW/cm2). Utilizing GaSe as the channel and InSe as the electrons trapped layer, the same experimental phenomenon is achieved. This work can provide an approach for designing a highly sensitive device utilizing a 2D van der Waals heterojunction, and it also possesses wide applicability for other materials.
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Affiliation(s)
- Huiming Shang
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin150080,China
- MOE Key Lab of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin150080, China
| | - Yunxia Hu
- MOE Key Lab of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin150080, China
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin150080, China
| | - Feng Gao
- MOE Key Lab of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin150080, China
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin150080, China
| | - Mingjin Dai
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore639798, Singapore
| | - Shichao Zhang
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin150080,China
- MOE Key Lab of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin150080, China
| | - Shuai Wang
- MOE Key Lab of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin150080, China
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin150080, China
| | - Decai Ouyang
- School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan430074, P. R. China
| | - Xinyu Li
- School of Physics, Harbin Institute of Technology, Harbin150080, China
| | - Xin Song
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin150080,China
- MOE Key Lab of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin150080, China
| | - Bo Gao
- School of Physics, Harbin Institute of Technology, Harbin150080, China
| | - Tianyou Zhai
- School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan430074, P. R. China
| | - PingAn Hu
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin150080,China
- MOE Key Lab of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin150080, China
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin150080, China
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin150080, China
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12
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Nayyar N, Le D, Turkowski V, Rahman TS. Electron-phonon interaction and ultrafast photoemission from doped monolayer MoS 2. Phys Chem Chem Phys 2022; 24:25298-25306. [PMID: 36226502 DOI: 10.1039/d2cp02905g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We have examined the effect of electron-phonon coupling on photoluminescence and ultrafast response of electron doped monolayer MoS2, using a combination of density functional theory, time dependent density functional theory, and many-body theory. For small doping (∼1-3%) of interest here, the electron-phonon coupling parameter is modest (∼0.1-0.2) but its effect on the emissive properties and response of the system to femtosecond (fs) laser pulses is striking. We find an ultrafast (fs) relaxation of the electronic subsystem as well as a high fluence of visible light emission induced by electron phonon interaction. Together with high carrier mobility, these features of monolayer MoS2 may be relevant for optoelectronic technologies.
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Affiliation(s)
- Neha Nayyar
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
| | - Duy Le
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
| | - Volodymyr Turkowski
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
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13
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Zhu H, Zan W, Chen W, Jiang W, Ding X, Li BL, Mu Y, Wang L, Garaj S, Leong DT. Defect-Rich Molybdenum Sulfide Quantum Dots for Amplified Photoluminescence and Photonics-Driven Reactive Oxygen Species Generation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2200004. [PMID: 35688799 DOI: 10.1002/adma.202200004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Transition metal dichalcogenide (TMD) quantum dots (QDs) with defects have attracted interesting chemistry due to the contribution of vacancies to their unique optical, physical, catalytic, and electrical properties. Engineering defined defects into molybdenum sulfide (MoS2 ) QDs is challenging. Herein, by applying a mild biomineralization-assisted bottom-up strategy, blue photoluminescent MoS2 QDs (B-QDs) with a high density of defects are fabricated. The two-stage synthesis begins with a bottom-up synthesis of original MoS2 QDs (O-QDs) through chemical reactions of Mo and sulfide ions, followed by alkaline etching that creates high sulfur-vacancy defects to eventually form B-QDs. Alkaline etching significantly increases the photoluminescence (PL) and photo-oxidation. An increase in defect density is shown to bring about increased active sites and decreased bandgap energy; which is further validated with density functional theory calculations. There is strengthened binding affinity between QDs and O2 due to lower gap energy (∆EST ) between S1 and T1 , accompanied with improved intersystem crossing (ISC) efficiency. Lowered gap energy contributes to assist e- -h+ pair formation and the strengthened binding affinity between QDs and 3 O2 . Defect engineering unravels another dimension of material properties control and can bring fresh new applications to otherwise well characterized TMD nanomaterials.
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Affiliation(s)
- Houjuan Zhu
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore
- Centre for Advanced 2D Materials, Graphene Research Centre, National University of Singapore, Singapore, 117546, Singapore
| | - Wenyan Zan
- Institute of Molecular Science, Shanxi University, Taiyuan, 034000, P. R. China
| | - Wanli Chen
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Wenbin Jiang
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore
| | - Xianguang Ding
- Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors, Nanjing University of Posts and Telecommunications, Nanjing, 210023, P. R. China
| | - Bang Lin Li
- Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, P. R. China
| | - Yuewen Mu
- Institute of Molecular Science, Shanxi University, Taiyuan, 034000, P. R. China
| | - Lei Wang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Slaven Garaj
- Centre for Advanced 2D Materials, Graphene Research Centre, National University of Singapore, Singapore, 117546, Singapore
- Department of Physics, National University of Singapore, Singapore, 117542, Singapore
- Department of Biomedical Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - David Tai Leong
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
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14
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Karni O, Esin I, Dani KM. Through the Lens of a Momentum Microscope: Viewing Light-Induced Quantum Phenomena in 2D Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2204120. [PMID: 35817468 DOI: 10.1002/adma.202204120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Van der Waals (vdW) materials at their 2D limit are diverse, flexible, and unique laboratories to study fundamental quantum phenomena and their future applications. Their novel properties rely on their pronounced Coulomb interactions, variety of crystal symmetries and spin-physics, and the ease of incorporation of different vdW materials to form sophisticated heterostructures. In particular, the excited state properties of many 2D semiconductors and semi-metals are relevant for their technological applications, particularly those that can be induced by light. In this paper, the recent advances made in studying out-of-equilibrium, light-induced, phenomena in these materials are reviewed using powerful, surface-sensitive, time-resolved photoemission-based techniques, with a particular emphasis on the emerging multi-dimensional photoemission spectroscopy technique of time-resolved momentum microscopy. The advances this technique has enabled in studying the nature and dynamics of occupied excited states in these materials are discussed. Then, the future research directions opened by these scientific and instrumental advancements are projected for studying the physics of 2D materials and the opportunities to engineer their band-structure and band-topology by laser fields.
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Affiliation(s)
- Ouri Karni
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Iliya Esin
- Department of Physics, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Keshav M Dani
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa, 904-0495, Japan
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15
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Liu XB, Hu SQ, Chen D, Guan M, Chen Q, Meng S. Calibrating Out-of-Equilibrium Electron-Phonon Couplings in Photoexcited MoS 2. NANO LETTERS 2022; 22:4800-4806. [PMID: 35648107 DOI: 10.1021/acs.nanolett.2c01105] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nonequilibrium electron-phonon coupling (EPC) serves as a dominant interaction in a multitude of transient processes, including photoinduced phase transitions, coherent phonon generation, and possible light-induced superconductivity. Here we use monolayer MoS2 as a prototype to investigate the variation in electron-phonon couplings under laser excitation, on the basis of real-time time-dependent density functional theory simulations. Phonon softening, anisotropic modification of the deformation potential, and enhancement of EPC are observed, which are attributed to the reduced electronic screening and modulated potential energy surfaces by photoexcitation. Furthermore, by tracking the transient deformation potential and nonthermal electronic population, we can monitor the ultrafast time evolution of the energy exchange rate between electrons and phonons upon laser excitation. This work provides an effective strategy to investigate the nonequilibrium EPC and constructs a scaffold for understanding nonequilibrium states beyond the multitemperature models.
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Affiliation(s)
- Xin-Bao Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Shi-Qi Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Daqiang Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Mengxue Guan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Qing Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
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16
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Trishin S, Lotze C, Bogdanoff N, von Oppen F, Franke KJ. Moiré Tuning of Spin Excitations: Individual Fe Atoms on MoS_{2}/Au(111). PHYSICAL REVIEW LETTERS 2021; 127:236801. [PMID: 34936798 DOI: 10.1103/physrevlett.127.236801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 10/14/2021] [Indexed: 06/14/2023]
Abstract
Magnetic adatoms on properly designed surfaces constitute exquisite systems for addressing, controlling, and manipulating single quantum spins. Here, we show that monolayers of MoS_{2} on a Au(111) surface provide a versatile platform for controllably tuning the coupling between adatom spins and substrate electrons. Even for equivalent adsorption sites with respect to the atomic MoS_{2} lattice, we observe that Fe adatoms exhibit behaviors ranging from pure spin excitations, characteristic of negligible exchange and dominant single-ion anisotropy, to a fully developed Kondo resonance, indicating strong exchange and negligible single-ion anisotropy. This tunability emerges from a moiré structure of MoS_{2} on Au(111) in conjunction with pronounced many-body renormalizations. We also find striking spectral variations in the immediate vicinity of the Fe atoms, which we explain by quantum interference reflecting the formation of Fe-S hybrid states despite the nominally inert nature of the substrate. Our work establishes monolayer MoS_{2} as a tuning layer for adjusting the quantum spin properties over an extraordinarily broad parameter range. The considerable variability can be exploited for quantum spin manipulations.
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Affiliation(s)
- Sergey Trishin
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Christian Lotze
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Nils Bogdanoff
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Felix von Oppen
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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17
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Lund HE, Volckaert K, Majchrzak P, Jones AJH, Bianchi M, Bremholm M, Hofmann P. Bulk band structure of Sb 2Te 3 determined by angle-resolved photoemission spectroscopy. Phys Chem Chem Phys 2021; 23:26401-26406. [PMID: 34792074 DOI: 10.1039/d1cp04031f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bulk band structure of the topological insulator Sb2Te3 is investigated by angle-resolved photoemission spectroscopy. Of particular interest is the dispersion of the uppermost valence band with respect to the topological surface state Dirac point. The valence band maximum has been calculated to be either near the Brillouin zone centre or in a low-symmetry position in the -M̄ azimuthal direction. In order to observe the full energy range of the valence band, the strongly p-doped crystals are counter-doped by surface alkali adsorption. The data show that the absolute valence band maximum is likely to be found at the bulk Γ point and predictions of a low-symmetry position with an energy higher than the surface Dirac point can be ruled out.
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Affiliation(s)
- Henriette E Lund
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Klara Volckaert
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Paulina Majchrzak
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Alfred J H Jones
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Marco Bianchi
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Martin Bremholm
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Philip Hofmann
- Department of Chemistry, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark.
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18
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Lee W, Lin Y, Lu LS, Chueh WC, Liu M, Li X, Chang WH, Kaindl RA, Shih CK. Time-resolved ARPES Determination of a Quasi-Particle Band Gap and Hot Electron Dynamics in Monolayer MoS 2. NANO LETTERS 2021; 21:7363-7370. [PMID: 34424691 DOI: 10.1021/acs.nanolett.1c02674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The electronic structure and dynamics of 2D transition metal dichalcogenide (TMD) monolayers provide important underpinnings both for understanding the many-body physics of electronic quasi-particles and for applications in advanced optoelectronic devices. However, extensive experimental investigations of semiconducting monolayer TMDs have yielded inconsistent results for a key parameter, the quasi-particle band gap (QBG), even for measurements carried out on the same layer and substrate combination. Here, we employ sensitive time- and angle-resolved photoelectron spectroscopy (trARPES) for a high-quality large-area MoS2 monolayer to capture its momentum-resolved equilibrium and excited-state electronic structure in the weak-excitation limit. For monolayer MoS2 on graphite, we obtain QBG values of ≈2.10 eV at 80 K and of ≈2.03 eV at 300 K, results well-corroborated by the scanning tunneling spectroscopy (STS) measurements on the same material.
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Affiliation(s)
- Woojoo Lee
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Yi Lin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Li-Syuan Lu
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Wei-Chen Chueh
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Mengke Liu
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Xiaoqin Li
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Wen-Hao Chang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
- Center for Emergent Functional Matter Science (CEFMS), National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Robert A Kaindl
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Physics and CXFEL Laboratory, Arizona State University, Tempe, Arizona 85287, United States
| | - Chih-Kang Shih
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
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19
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Lloyd-Hughes J, Oppeneer PM, Pereira Dos Santos T, Schleife A, Meng S, Sentef MA, Ruggenthaler M, Rubio A, Radu I, Murnane M, Shi X, Kapteyn H, Stadtmüller B, Dani KM, da Jornada FH, Prinz E, Aeschlimann M, Milot RL, Burdanova M, Boland J, Cocker T, Hegmann F. The 2021 ultrafast spectroscopic probes of condensed matter roadmap. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:353001. [PMID: 33951618 DOI: 10.1088/1361-648x/abfe21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 05/05/2021] [Indexed: 06/12/2023]
Abstract
In the 60 years since the invention of the laser, the scientific community has developed numerous fields of research based on these bright, coherent light sources, including the areas of imaging, spectroscopy, materials processing and communications. Ultrafast spectroscopy and imaging techniques are at the forefront of research into the light-matter interaction at the shortest times accessible to experiments, ranging from a few attoseconds to nanoseconds. Light pulses provide a crucial probe of the dynamical motion of charges, spins, and atoms on picosecond, femtosecond, and down to attosecond timescales, none of which are accessible even with the fastest electronic devices. Furthermore, strong light pulses can drive materials into unusual phases, with exotic properties. In this roadmap we describe the current state-of-the-art in experimental and theoretical studies of condensed matter using ultrafast probes. In each contribution, the authors also use their extensive knowledge to highlight challenges and predict future trends.
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Affiliation(s)
- J Lloyd-Hughes
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - P M Oppeneer
- Department of Physics and Astronomy, Uppsala University, PO Box 516, S-75120 Uppsala, Sweden
| | - T Pereira Dos Santos
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - A Schleife
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - S Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - M A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
| | - M Ruggenthaler
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
| | - A Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
- Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco UPV/EHU 20018 San Sebastián, Spain
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, 162 Fifth Avenue, New York, NY, 10010, United States of America
| | - I Radu
- Department of Physics, Freie Universität Berlin, Germany
- Max Born Institute, Berlin, Germany
| | - M Murnane
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - X Shi
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - H Kapteyn
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - B Stadtmüller
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - K M Dani
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan
| | - F H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, 94305, CA, United States of America
| | - E Prinz
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - M Aeschlimann
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - R L Milot
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - M Burdanova
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - J Boland
- Photon Science Institute, Department of Electrical and Electronic Engineering, University of Manchester, United Kingdom
| | - T Cocker
- Michigan State University, United States of America
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20
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Sorgenfrei NLAN, Giangrisostomi E, Jay RM, Kühn D, Neppl S, Ovsyannikov R, Sezen H, Svensson S, Föhlisch A. Photodriven Transient Picosecond Top-Layer Semiconductor to Metal Phase-Transition in p-Doped Molybdenum Disulfide. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006957. [PMID: 33661532 DOI: 10.1002/adma.202006957] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/23/2020] [Indexed: 06/12/2023]
Abstract
Visible light is shown to create a transient metallic S-Mo-S surface layer on bulk semiconducting p-doped indirect-bandgap 2H-MoS2 . Optically created electron-hole pairs separate in the surface band bending region of the p-doped semiconducting crystal causing a transient accumulation of electrons in the surface region. This triggers a reversible 2H-semiconductor to 1T-metal phase-transition of the surface layer. Electron-phonon coupling of the indirect-bandgap p-doped 2H-MoS2 enables this efficient pathway even at a low density of excited electrons with a distinct optical excitation threshold and saturation behavior. This mechanism needs to be taken into consideration when describing the surface properties of illuminated p-doped 2H-MoS2 . In particular, light-induced increased charge mobility and surface activation can cause and enhance the photocatalytic and photoassisted electrochemical hydrogen evolution reaction of water on 2H-MoS2 . Generally, it opens up for a way to control not only the surface of p-doped 2H-MoS2 but also related dichalcogenides and layered systems. The findings are based on the sensitivity of time-resolved electron spectroscopy for chemical analysis with photon-energy-tuneable synchrotron radiation.
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Affiliation(s)
- Nomi L A N Sorgenfrei
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476, Potsdam, Germany
| | - Erika Giangrisostomi
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Raphael M Jay
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Danilo Kühn
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476, Potsdam, Germany
| | - Stefan Neppl
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Ruslan Ovsyannikov
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Hikmet Sezen
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Svante Svensson
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden
| | - Alexander Föhlisch
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476, Potsdam, Germany
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
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21
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King PDC, Picozzi S, Egdell RG, Panaccione G. Angle, Spin, and Depth Resolved Photoelectron Spectroscopy on Quantum Materials. Chem Rev 2021; 121:2816-2856. [PMID: 33346644 DOI: 10.1021/acs.chemrev.0c00616] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of X-ray based electron spectroscopies in determining chemical, electronic, and magnetic properties of solids has been well-known for several decades. A powerful approach is angle-resolved photoelectron spectroscopy, whereby the kinetic energy and angle of photoelectrons emitted from a sample surface are measured. This provides a direct measurement of the electronic band structure of crystalline solids. Moreover, it yields powerful insights into the electronic interactions at play within a material and into the control of spin, charge, and orbital degrees of freedom, central pillars of future solid state science. With strong recent focus on research of lower-dimensional materials and modified electronic behavior at surfaces and interfaces, angle-resolved photoelectron spectroscopy has become a core technique in the study of quantum materials. In this review, we provide an introduction to the technique. Through examples from several topical materials systems, including topological insulators, transition metal dichalcogenides, and transition metal oxides, we highlight the types of information which can be obtained. We show how the combination of angle, spin, time, and depth-resolved experiments are able to reveal "hidden" spectral features, connected to semiconducting, metallic and magnetic properties of solids, as well as underlining the importance of dimensional effects in quantum materials.
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Affiliation(s)
- Phil D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche, CNR-SPIN, Via dei Vestini 31, Chieti 66100, Italy
| | - Russell G Egdell
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
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22
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Abstract
The coupled nonequilibrium dynamics of electrons and phonons in monolayer MoS2 is investigated by combining first-principles calculations of the electron-phonon and phonon-phonon interactions with the time-dependent Boltzmann equation. Strict phase-space constraints in the electron-phonon scattering are found to influence profoundly the decay path of excited electrons and holes, restricting the emission of phonons to crystal momenta close to a few high-symmetry points in the Brillouin zone. As a result of momentum selectivity in the phonon emission, the nonequilibrium lattice dynamics is characterized by the emergence of a highly anisotropic population of phonons in reciprocal space, which persists for up to 10 ps until thermal equilibrium is restored by phonon-phonon scattering. Achieving control of the nonequilibrium dynamics of the lattice may provide unexplored opportunities to selectively enhance the phonon population of two-dimensional crystals and, thereby, transiently tailor electron-phonon interactions over subpicosecond time scales.
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Affiliation(s)
- Fabio Caruso
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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23
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Xu C, Yong HW, He J, Long R, Cadore AR, Paradisanos I, Ott AK, Soavi G, Tongay S, Cerullo G, Ferrari AC, Prezhdo OV, Loh ZH. Weak Distance Dependence of Hot-Electron-Transfer Rates at the Interface between Monolayer MoS 2 and Gold. ACS NANO 2021; 15:819-828. [PMID: 33347267 DOI: 10.1021/acsnano.0c07350] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electron transport across the transition-metal dichalcogenide (TMD)/metal interface plays an important role in determining the performance of TMD-based optoelectronic devices. However, the robustness of this process against structural heterogeneities remains unexplored, to the best of our knowledge. Here, we employ a combination of time-resolved photoemission electron microscopy (TR-PEEM) and atomic force microscopy to investigate the spatially resolved hot-electron-transfer dynamics at the monolayer (1L) MoS2/Au interface. A spatially heterogeneous distribution of 1L-MoS2/Au gap distances, along with the sub-80 nm spatial- and sub-60 fs temporal resolution of TR-PEEM, permits the simultaneous measurement of electron-transfer rates across a range of 1L-MoS2/Au distances. These decay exponentially as a function of distance, with an attenuation coefficient β ∼ 0.06 ± 0.01 Å-1, comparable to molecular wires. Ab initio simulations suggest that surface plasmon-like states mediate hot-electron-transfer, hence accounting for its weak distance dependence. The weak distance dependence of the interfacial hot-electron-transfer rate indicates that this process is insensitive to distance fluctuations at the TMD/metal interface, thus motivating further exploration of optoelectronic devices based on hot carriers.
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Affiliation(s)
- Ce Xu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Hui Wen Yong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Jinlu He
- College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical and Computational Photochemistry, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Alisson R Cadore
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Ioannis Paradisanos
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Anna K Ott
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Giancarlo Soavi
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
- Institute for Solid State Physics, Abbe Center of Photonics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Giulio Cerullo
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano Italy
- IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- Centre for Optical Fibre Technology, The Photonics Institute, Nanyang Technological University, Singapore 639798, Singapore
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24
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Madéo J, Man MKL, Sahoo C, Campbell M, Pareek V, Wong EL, Al-Mahboob A, Chan NS, Karmakar A, Mariserla BMK, Li X, Heinz TF, Cao T, Dani KM. Directly visualizing the momentum-forbidden dark excitons and their dynamics in atomically thin semiconductors. Science 2021; 370:1199-1204. [PMID: 33273099 DOI: 10.1126/science.aba1029] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 09/29/2020] [Indexed: 12/14/2022]
Abstract
Resolving momentum degrees of freedom of excitons, which are electron-hole pairs bound by the Coulomb attraction in a photoexcited semiconductor, has remained an elusive goal for decades. In atomically thin semiconductors, such a capability could probe the momentum-forbidden dark excitons, which critically affect proposed opto-electronic technologies but are not directly accessible using optical techniques. Here, we probed the momentum state of excitons in a tungsten diselenide monolayer by photoemitting their constituent electrons and resolving them in time, momentum, and energy. We obtained a direct visual of the momentum-forbidden dark excitons and studied their properties, including their near degeneracy with bright excitons and their formation pathways in the energy-momentum landscape. These dark excitons dominated the excited-state distribution, a surprising finding that highlights their importance in atomically thin semiconductors.
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Affiliation(s)
- Julien Madéo
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495
| | - Michael K L Man
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495
| | - Chakradhar Sahoo
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495.,School of Physics, University of Hyderabad, Gachibowli, Hyderabad-500046, Telangana, India
| | - Marshall Campbell
- Physics Department, Center for Complex Quantum System, The University of Texas at Austin, Austin, TX 78712, USA
| | - Vivek Pareek
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495
| | - E Laine Wong
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495
| | - Abdullah Al-Mahboob
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495
| | - Nicholas S Chan
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495
| | - Arka Karmakar
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495
| | - Bala Murali Krishna Mariserla
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495.,Department of Physics, Indian Institute of Technology, Jodhpur, Rajasthan, India 342037
| | - Xiaoqin Li
- Physics Department, Center for Complex Quantum System, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tony F Heinz
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.,SLAC National Accelerator Laboratory, Menlo Park, CA 94720, USA
| | - Ting Cao
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.,Department of Materials Sciences and Engineering, University of Washington, Seattle, WA 98195, USA
| | - Keshav M Dani
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495.
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25
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Maklar J, Dong S, Beaulieu S, Pincelli T, Dendzik M, Windsor YW, Xian RP, Wolf M, Ernstorfer R, Rettig L. A quantitative comparison of time-of-flight momentum microscopes and hemispherical analyzers for time- and angle-resolved photoemission spectroscopy experiments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:123112. [PMID: 33379994 DOI: 10.1063/5.0024493] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/26/2020] [Indexed: 06/12/2023]
Abstract
Time-of-flight-based momentum microscopy has a growing presence in photoemission studies, as it enables parallel energy- and momentum-resolved acquisition of the full photoelectron distribution. Here, we report table-top extreme ultraviolet time- and angle-resolved photoemission spectroscopy (trARPES) featuring both a hemispherical analyzer and a momentum microscope within the same setup. We present a systematic comparison of the two detection schemes and quantify experimentally relevant parameters, including pump- and probe-induced space-charge effects, detection efficiency, photoelectron count rates, and depth of focus. We highlight the advantages and limitations of both instruments based on exemplary trARPES measurements of bulk WSe2. Our analysis demonstrates the complementary nature of the two spectrometers for time-resolved ARPES experiments. Their combination in a single experimental apparatus allows us to address a broad range of scientific questions with trARPES.
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Affiliation(s)
- J Maklar
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - S Dong
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - S Beaulieu
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - T Pincelli
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - M Dendzik
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Y W Windsor
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - R P Xian
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - M Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - R Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - L Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
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26
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Chu Z, Wang CY, Quan J, Zhang C, Lei C, Han A, Ma X, Tang HL, Abeysinghe D, Staab M, Zhang X, MacDonald AH, Tung V, Li X, Shih CK, Lai K. Unveiling defect-mediated carrier dynamics in monolayer semiconductors by spatiotemporal microwave imaging. Proc Natl Acad Sci U S A 2020; 117:13908-13913. [PMID: 32513713 PMCID: PMC7322012 DOI: 10.1073/pnas.2004106117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The optoelectronic properties of atomically thin transition-metal dichalcogenides are strongly correlated with the presence of defects in the materials, which are not necessarily detrimental for certain applications. For instance, defects can lead to an enhanced photoconduction, a complicated process involving charge generation and recombination in the time domain and carrier transport in the spatial domain. Here, we report the simultaneous spatial and temporal photoconductivity imaging in two types of WS2 monolayers by laser-illuminated microwave impedance microscopy. The diffusion length and carrier lifetime were directly extracted from the spatial profile and temporal relaxation of microwave signals, respectively. Time-resolved experiments indicate that the critical process for photoexcited carriers is the escape of holes from trap states, which prolongs the apparent lifetime of mobile electrons in the conduction band. As a result, counterintuitively, the long-lived photoconductivity signal is higher in chemical-vapor deposited (CVD) samples than exfoliated monolayers due to the presence of traps that inhibits recombination. Our work reveals the intrinsic time and length scales of electrical response to photoexcitation in van der Waals materials, which is essential for their applications in optoelectronic devices.
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Affiliation(s)
- Zhaodong Chu
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Chun-Yuan Wang
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Jiamin Quan
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Chenhui Zhang
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, 23955-6900 Thuwal, Kingdom of Saudi Arabia
| | - Chao Lei
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Ali Han
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, 23955-6900 Thuwal, Kingdom of Saudi Arabia
| | - Xuejian Ma
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Hao-Ling Tang
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, 23955-6900 Thuwal, Kingdom of Saudi Arabia
| | - Dishan Abeysinghe
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Matthew Staab
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Xixiang Zhang
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, 23955-6900 Thuwal, Kingdom of Saudi Arabia
| | - Allan H MacDonald
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Vincent Tung
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, 23955-6900 Thuwal, Kingdom of Saudi Arabia
| | - Xiaoqin Li
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Chih-Kang Shih
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Keji Lai
- Department of Physics, The University of Texas at Austin, Austin, TX 78712;
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27
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Li Y, Liu W, Wang Y, Xue Z, Leng YC, Hu A, Yang H, Tan PH, Liu Y, Misawa H, Sun Q, Gao Y, Hu X, Gong Q. Ultrafast Electron Cooling and Decay in Monolayer WS 2 Revealed by Time- and Energy-Resolved Photoemission Electron Microscopy. NANO LETTERS 2020; 20:3747-3753. [PMID: 32242668 DOI: 10.1021/acs.nanolett.0c00742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A comprehensive understanding of the ultrafast electron dynamics in two-dimensional transition metal dichalcogenides (TMDs) is necessary for their applications in optoelectronic devices. In this work, we contribute a study of ultrafast electron cooling and decay dynamics in the supported and suspended monolayer WS2 by time- and energy-resolved photoemission electron microscopy (PEEM). Electron cooling in the Q valley of the conduction band is clearly resolved in energy and time, on a time scale of 0.3 ps. Electron decay is mainly via a defect trapping process on a time scale of several picoseconds. We observed that the trap states can be produced and increased by laser illumination under an ultrahigh vacuum, and the higher local optical-field intensity led to the faster increase of trap states. The enhanced defect trapping could significantly modify the carrier dynamics and should be paid attention to in photoemission experiments for two-dimensional materials.
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Affiliation(s)
- Yaolong Li
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Wei Liu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Yunkun Wang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Zhaohang Xue
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Yu-Chen Leng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Aiqin Hu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Hong Yang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yunquan Liu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Hiroaki Misawa
- Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0021, Japan
- Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Quan Sun
- Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0021, Japan
| | - Yunan Gao
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Xiaoyong Hu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Qihuang Gong
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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28
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Pan C, Jiang L, Sun J, Wang Q, Wang F, Wang K, Lu Y, Wang Y, Qu L, Cui T. Ultrafast optical response and ablation mechanisms of molybdenum disulfide under intense femtosecond laser irradiation. LIGHT, SCIENCE & APPLICATIONS 2020; 9:80. [PMID: 32411365 PMCID: PMC7203173 DOI: 10.1038/s41377-020-0318-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 04/10/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
Numerous valuable studies on electron dynamics have focussed on the extraordinary properties of molybdenum disulfide (MoS2); however, most of them were confined to the level below the damage threshold. Here the electron dynamics of MoS2 under intense ultrafast laser irradiation was investigated by experiments and simulations. Two kinds of ablation mechanisms were revealed, which led to two distinct types of electron dynamics and final ablation morphology. At a higher fluence, the emergence of superheated liquid induced a dramatic change in the transient reflectivity and micro-honeycomb structures. At a lower fluence, the material was just removed by sublimation, and the ablation structure was relatively flat. X-ray photoelectron spectroscopic (XPS) measurements demonstrated that thermal decomposition only occurred at the higher fluence. Furthermore, a theoretical model was developed to deeply reveal the ultrafast dynamics of MoS2 ablation. The simulation results were in good agreement with the temporal and spatial reflectivity distribution obtained from the experiment. The electron and lattice temperature evolution was also obtained to prove the ablation mechanism. Our results revealed ultrafast dynamics of MoS2 above the damage threshold and are helpful for understanding the interaction mechanism between MoS2 and intense ultrafast lasers, as well as for MoS2 processing applications.
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Affiliation(s)
- Changji Pan
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, 100081 Beijing, P.R. China
| | - Lan Jiang
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, 100081 Beijing, P.R. China
| | - Jingya Sun
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, 100081 Beijing, P.R. China
| | - Qingsong Wang
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, 100081 Beijing, P.R. China
| | - Feifei Wang
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, 100081 Beijing, P.R. China
| | - Kai Wang
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, 100081 Beijing, P.R. China
| | - Yongfeng Lu
- Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0511 USA
| | - Yeliang Wang
- School of Information and Electronics, Beijing Institute of Technology, 100081 Beijing, P.R. China
| | - Liangti Qu
- Key Laboratory for Advanced Materials Processing Technology, Ministry of Education of China, Department of Mechanical Engineering, Tsinghua University, 100084 Beijing, P.R. China
| | - Tianhong Cui
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 USA
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29
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Linardy E, Yadav D, Vella D, Verzhbitskiy IA, Watanabe K, Taniguchi T, Pauly F, Trushin M, Eda G. Harnessing Exciton-Exciton Annihilation in Two-Dimensional Semiconductors. NANO LETTERS 2020; 20:1647-1653. [PMID: 32078334 DOI: 10.1021/acs.nanolett.9b04756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Strong many-body interactions in two-dimensional (2D) semiconductors give rise to efficient exciton-exciton annihilation (EEA). This process is expected to result in the generation of unbound high energy carriers. Here, we report an unconventional photoresponse of van der Waals heterostructure devices resulting from efficient EEA. Our heterostructures, which consist of monolayer transition metal dichalcogenide (TMD), hexagonal boron nitride (hBN), and few-layer graphene, exhibit photocurrent when photoexcited carriers possess sufficient energy to overcome the high energy barrier of hBN. Interestingly, we find that the device exhibits moderate photocurrent quantum efficiency even when the semiconducting TMD layer is excited at its ground exciton resonance despite the high exciton binding energy and large transport barrier. Using ab initio calculations, we show that EEA yields highly energetic electrons and holes with unevenly distributed energies depending on the scattering condition. Our findings highlight the dominant role of EEA in determining the photoresponse of 2D semiconductor optoelectronic devices.
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Affiliation(s)
- Eric Linardy
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 21 Lower Kent Ridge, Singapore 119077, Singapore
| | - Dinesh Yadav
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Daniele Vella
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
| | - Ivan A Verzhbitskiy
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
| | - Kenji Watanabe
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Fabian Pauly
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Maxim Trushin
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
| | - Goki Eda
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
- Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
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30
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Dal Conte S, Trovatello C, Gadermaier C, Cerullo G. Ultrafast Photophysics of 2D Semiconductors and Related Heterostructures. TRENDS IN CHEMISTRY 2020. [DOI: 10.1016/j.trechm.2019.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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31
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Beyer H, Rohde G, Grubišić Čabo A, Stange A, Jacobsen T, Bignardi L, Lizzit D, Lacovig P, Sanders CE, Lizzit S, Rossnagel K, Hofmann P, Bauer M. 80% Valley Polarization of Free Carriers in Singly Oriented Single-Layer WS_{2} on Au(111). PHYSICAL REVIEW LETTERS 2019; 123:236802. [PMID: 31868459 DOI: 10.1103/physrevlett.123.236802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Indexed: 06/10/2023]
Abstract
We employ time- and angle-resolved photoemission spectroscopy to study the spin- and valley-selective photoexcitation and dynamics of free carriers at the K[over ¯] and K[over ¯]^{'} points in singly oriented single-layer WS_{2}/Au(111). Our results reveal that in the valence band maximum an ultimate valley polarization of free holes of 84% can be achieved upon excitation with circularly polarized light at room temperature. Notably, we observe a significantly smaller valley polarization for the photoexcited free electrons in the conduction band minimum. Clear differences in the carrier dynamics between electrons and holes imply intervalley scattering processes into dark states being responsible for the efficient depolarization of the excited electron population.
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Affiliation(s)
- H Beyer
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - G Rohde
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - A Grubišić Čabo
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| | - A Stange
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - T Jacobsen
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - L Bignardi
- Department of Physics, University of Trieste, 34127 Trieste, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - D Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - P Lacovig
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - C E Sanders
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell OX11 0QX, United Kingdom
| | - S Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - K Rossnagel
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
- Ruprecht-Haensel-Labor, Christian-Albrechts-Universität zu Kiel und Deutsches Elektronen-Synchrotron DESY, 24098 Kiel und 22607 Hamburg, Germany
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - P Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
| | - M Bauer
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
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32
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Xie XY, Liu XY, Fang Q, Fang WH, Cui G. Photoinduced Carrier Dynamics at the Interface of Pentacene and Molybdenum Disulfide. J Phys Chem A 2019; 123:7693-7703. [PMID: 31419385 DOI: 10.1021/acs.jpca.9b04728] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Understanding of photoinduced interfacial carrier dynamics in organic-transition metal dichalcogenides heterostructures is very important for the enhancement of their potential photoelectronic conversion efficiencies. In this work we have used density functional theory (DFT) calculations and DFT-based fewest-switches surface-hopping dynamics simulations to explore the photoinduced hole transfer and subsequent nonadiabatic electron-hole recombination dynamics taking place at the interface of pentacene and MoS2 in pentacene@MoS2. Upon photoexcitation the electronic transition mainly occurs on the MoS2 monolayer, which corresponds to moving an electron to the MoS2 conduction band. As a result, a hole is left in the valence band. This hole state is energetically lower than certain occupied states of the pentacene molecule; thus, the interfacial hole transfer from MoS2 to pentacene is favorable in energy. In terms of nonadiabatic dynamics simulations, the hole transfer time to the HOMO-1 state of the pentacene is estimated to be about 600 fs; however, the following hole relaxation process from HOMO-1 to HOMO takes much longer time of ca. 15 ps due to the large energy gap between HOMO-1 and HOMO. Moreover, our results also show that the subsequent radiationless recombination process between the hole transferred to the pentacene molecule and the remaining electron on the MoS2 CBM needs about 10.2 ns. The computational results shed important mechanistic insights on the interfacial carrier dynamics of mixed-dimensional pentacene@MoS2. These insights could help to design excellent interfaces for organic-TMDs heterostructures.
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Affiliation(s)
- Xiao-Ying Xie
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Xiang-Yang Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Qiu Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry , Beijing Normal University , Beijing 100875 , China
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33
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Ulstrup S, Giusca CE, Miwa JA, Sanders CE, Browning A, Dudin P, Cacho C, Kazakova O, Gaskill DK, Myers-Ward RL, Zhang T, Terrones M, Hofmann P. Nanoscale mapping of quasiparticle band alignment. Nat Commun 2019; 10:3283. [PMID: 31337765 PMCID: PMC6650412 DOI: 10.1038/s41467-019-11253-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/02/2019] [Indexed: 11/22/2022] Open
Abstract
Control of atomic-scale interfaces between materials with distinct electronic structures is crucial for the design and fabrication of most electronic devices. In the case of two-dimensional materials, disparate electronic structures can be realized even within a single uniform sheet, merely by locally applying different vertical gate voltages. Here, we utilize the inherently nano-structured single layer and bilayer graphene on silicon carbide to investigate lateral electronic structure variations in an adjacent single layer of tungsten disulfide (WS2). The electronic band alignments are mapped in energy and momentum space using angle-resolved photoemission with a spatial resolution on the order of 500 nm (nanoARPES). We find that the WS2 band offsets track the work function of the underlying single layer and bilayer graphene, and we relate such changes to observed lateral patterns of exciton and trion luminescence from WS2. Sharp atomic interfaces between materials dictate the interface’s electronic properties. The authors use angle-resolved photoemission spectroscopy with a spatial resolution of ~500 nm to investigate the nanoscale electronic band structure and band alignment in a lateral heterostructure composed of WS2 placed on alternating nano-stripes of monolayer and bilayer graphene.
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Affiliation(s)
- Søren Ulstrup
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark.
| | - Cristina E Giusca
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK.
| | - Jill A Miwa
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark
| | - Charlotte E Sanders
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Alex Browning
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Pavel Dudin
- Diamond Light Source, Division of Science, Didcot, OX11 0DE, UK
| | - Cephise Cacho
- Diamond Light Source, Division of Science, Didcot, OX11 0DE, UK
| | - Olga Kazakova
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - D Kurt Gaskill
- U.S. Naval Research Laboratory, Washington, DC, 20375, USA
| | | | - Tianyi Zhang
- Department of Physics and Center for 2-Dimensional and Layered Materials, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mauricio Terrones
- Department of Physics and Center for 2-Dimensional and Layered Materials, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Philip Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark
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34
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Liu F, Ziffer ME, Hansen KR, Wang J, Zhu X. Direct Determination of Band-Gap Renormalization in the Photoexcited Monolayer MoS_{2}. PHYSICAL REVIEW LETTERS 2019; 122:246803. [PMID: 31322407 DOI: 10.1103/physrevlett.122.246803] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Indexed: 06/10/2023]
Abstract
A key feature of monolayer semiconductors, such as transition-metal dichalcogenides, is the poorly screened Coulomb potential, which leads to a large exciton binding energy (E_{b}) and strong renormalization of the quasiparticle band gap (E_{g}) by carriers. The latter has been difficult to determine due to a cancellation in changes of E_{b} and E_{g}, resulting in little change in optical transition energy at different carrier densities. Here, we quantify band-gap renormalization in macroscopic single crystal MoS_{2} monolayers on SiO_{2} using time and angle-resolved photoemission spectroscopy. At an excitation density above the Mott threshold, E_{g} decreases by as much as 360 meV. We compare the carrier density-dependent E_{g} with previous theoretical calculations and show the necessity of knowing both doping and excitation densities in quantifying the band gap.
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Affiliation(s)
- Fang Liu
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Mark E Ziffer
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Kameron R Hansen
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Jue Wang
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, New York, New York 10027, USA
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35
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Ma EY, Guzelturk B, Li G, Cao L, Shen ZX, Lindenberg AM, Heinz TF. Recording interfacial currents on the subnanometer length and femtosecond time scale by terahertz emission. SCIENCE ADVANCES 2019; 5:eaau0073. [PMID: 30783622 PMCID: PMC6368434 DOI: 10.1126/sciadv.aau0073] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 12/19/2018] [Indexed: 05/22/2023]
Abstract
Electron dynamics at interfaces is a subject of great scientific interest and technological importance. Detailed understanding of such dynamics requires access to the angstrom length scale defining interfaces and the femtosecond time scale characterizing interfacial motion of electrons. In this context, the most precise and general way to remotely measure charge dynamics is through the transient current flow and the associated electromagnetic radiation. Here, we present quantitative measurements of interfacial currents on the subnanometer length and femtosecond time scale by recording the emitted terahertz radiation following ultrafast laser excitation. We apply this method to interlayer charge transfer in heterostructures of two transition metal dichalcogenide monolayers less than 0.7 nm apart. We find that charge relaxation and separation occur in less than 100 fs. This approach allows us to unambiguously determine the direction of current flow, to demonstrate a charge transfer efficiency of order unity, and to characterize saturation effects.
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Affiliation(s)
- Eric Yue Ma
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Burak Guzelturk
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Guoqing Li
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Linyou Cao
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Zhi-Xun Shen
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Aaron M. Lindenberg
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Tony F. Heinz
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Corresponding author.
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36
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Buss JH, Wang H, Xu Y, Maklar J, Joucken F, Zeng L, Stoll S, Jozwiak C, Pepper J, Chuang YD, Denlinger JD, Hussain Z, Lanzara A, Kaindl RA. A setup for extreme-ultraviolet ultrafast angle-resolved photoelectron spectroscopy at 50-kHz repetition rate. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:023105. [PMID: 30831755 DOI: 10.1063/1.5079677] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Time- and angle-resolved photoelectron spectroscopy (trARPES) is a powerful method to track the ultrafast dynamics of quasiparticles and electronic bands in energy and momentum space. We present a setup for trARPES with 22.3 eV extreme-ultraviolet (XUV) femtosecond pulses at 50-kHz repetition rate, which enables fast data acquisition and access to dynamics across momentum space with high sensitivity. The design and operation of the XUV beamline, pump-probe setup, and ultra-high vacuum endstation are described in detail. By characterizing the effect of space-charge broadening, we determine an ultimate source-limited energy resolution of 60 meV, with typically 80-100 meV obtained at 1-2 × 1010 photons/s probe flux on the sample. The instrument capabilities are demonstrated via both equilibrium and time-resolved ARPES studies of transition-metal dichalcogenides. The 50-kHz repetition rate enables sensitive measurements of quasiparticles at low excitation fluences in semiconducting MoSe2, with an instrumental time resolution of 65 fs. Moreover, photo-induced phase transitions can be driven with the available pump fluence, as shown by charge density wave melting in 1T-TiSe2. The high repetition-rate setup thus provides a versatile platform for sensitive XUV trARPES, from quenching of electronic phases down to the perturbative limit.
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Affiliation(s)
- Jan Heye Buss
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - He Wang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Yiming Xu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Julian Maklar
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Frederic Joucken
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Lingkun Zeng
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Sebastian Stoll
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - John Pepper
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Yi-De Chuang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Zahid Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Alessandra Lanzara
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Robert A Kaindl
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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37
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Krane N, Lotze C, Reecht G, Zhang L, Briseno AL, Franke KJ. High-Resolution Vibronic Spectra of Molecules on Molybdenum Disulfide Allow for Rotamer Identification. ACS NANO 2018; 12:11698-11703. [PMID: 30380829 DOI: 10.1021/acsnano.8b07414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tunneling spectroscopy is an important tool for the chemical identification of single molecules on surfaces. Here, we show that oligothiophene-based large organic molecules which only differ by single bond orientations can be distinguished by their vibronic fingerprint. These molecules were deposited on a monolayer of the transition metal dichalcogenide molybdenum disulfide (MoS2) on top of a Au(111) substrate. MoS2 features an electronic band gap for efficient decoupling of the molecular states. Furthermore, it exhibits a small electron-phonon coupling strength. Both of these material properties allow for the resolution of vibronic states in the range of the limit set by temperature broadening in our scanning tunneling microscope at 4.6 K. Using DFT calculations of the molecule in gas phase provides all details for an accurate simulation of the vibronic spectra of both rotamers.
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Affiliation(s)
- Nils Krane
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Christian Lotze
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Gaël Reecht
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Lei Zhang
- Department of Polymer Science and Engineering , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Alejandro L Briseno
- Department of Polymer Science and Engineering , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Katharina J Franke
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
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38
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Liu XY, Xie XY, Fang WH, Cui G. Theoretical Insights into Interfacial Electron Transfer between Zinc Phthalocyanine and Molybdenum Disulfide. J Phys Chem A 2018; 122:9587-9596. [DOI: 10.1021/acs.jpca.8b07816] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Xiang-Yang Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xiao-Ying Xie
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
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39
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Eickholt P, Sanders C, Dendzik M, Bignardi L, Lizzit D, Lizzit S, Bruix A, Hofmann P, Donath M. Spin Structure of K Valleys in Single-Layer WS_{2} on Au(111). PHYSICAL REVIEW LETTERS 2018; 121:136402. [PMID: 30312046 DOI: 10.1103/physrevlett.121.136402] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/19/2018] [Indexed: 06/08/2023]
Abstract
The spin structure of the valence and conduction bands at the K[over ¯] and K[over ¯]^{'} valleys of single-layer WS_{2} on Au(111) is determined by spin- and angle-resolved photoemission and inverse photoemission. The bands confining the direct band gap of 1.98 eV are out-of-plane spin polarized with spin-dependent energy splittings of 417 meV in the valence band and 16 meV in the conduction band. The sequence of the spin-split bands is the same in the valence and in the conduction bands and opposite at the K[over ¯] and the K[over ¯]^{'} high-symmetry points. The first observation explains "dark" excitons discussed in optical experiments; the latter points to coupled spin and valley physics in electron transport. The experimentally observed band dispersions are discussed along with band structure calculations for a freestanding single layer and for a single layer on Au(111).
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Affiliation(s)
- Philipp Eickholt
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Charlotte Sanders
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Maciej Dendzik
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Luca Bignardi
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - Daniel Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - Silvano Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - Albert Bruix
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Philip Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Markus Donath
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
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40
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Kim W, Arpiainen S, Xue H, Soikkeli M, Qi M, Sun Z, Lipsanen H, Chaves FA, Jiménez D, Prunnila M. Photoresponse of Graphene-Gated Graphene-GaSe Heterojunction Devices. ACS APPLIED NANO MATERIALS 2018; 1:3895-3902. [PMID: 30259010 PMCID: PMC6150651 DOI: 10.1021/acsanm.8b00684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/31/2018] [Indexed: 05/13/2023]
Abstract
Because of their extraordinary physical properties, low-dimensional materials including graphene and gallium selenide (GaSe) are promising for future electronic and optoelectronic applications, particularly in transparent-flexible photodetectors. Currently, the photodetectors working at the near-infrared spectral range are highly indispensable in optical communications. However, the current photodetector architectures are typically complex, and it is normally difficult to control the architecture parameters. Here, we report graphene-GaSe heterojunction-based field-effect transistors with broadband photodetection from 730-1550 nm. Chemical-vapor-deposited graphene was employed as transparent gate and contact electrodes with tunable resistance, which enables effective photocurrent generation in the heterojunctions. The photoresponsivity was shown from 10 to 0.05 mA/W in the near-infrared region under the gate control. To understand behavior of the transistor, we analyzed the results via simulation performed using a model for the gate-tunable graphene-semiconductor heterojunction where possible Fermi level pinning effect is considered.
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Affiliation(s)
- Wonjae Kim
- VTT
Technical Research Center of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland
| | - Sanna Arpiainen
- VTT
Technical Research Center of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland
- E-mail:
| | - Hui Xue
- Department
of Electronics and Nanoengineering, Aalto
University, Tietotie 3, Espoo 02150, Finland
| | - Miika Soikkeli
- VTT
Technical Research Center of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland
| | - Mei Qi
- Department
of Electronics and Nanoengineering, Aalto
University, Tietotie 3, Espoo 02150, Finland
| | - Zhipei Sun
- Department
of Electronics and Nanoengineering, Aalto
University, Tietotie 3, Espoo 02150, Finland
- QTF
Centre of Excellence, Department of Applied Physics, Aalto University, Aalto FI-00076, Finland
| | - Harri Lipsanen
- Department
of Electronics and Nanoengineering, Aalto
University, Tietotie 3, Espoo 02150, Finland
| | - Ferney A. Chaves
- Department
d’Enginyeria Electrònica, Escola d’Enginyeria, Universitat Autònoma de Barcelona, Campus UAB, Bellaterra E-08193, Spain
| | - David Jiménez
- Department
d’Enginyeria Electrònica, Escola d’Enginyeria, Universitat Autònoma de Barcelona, Campus UAB, Bellaterra E-08193, Spain
| | - Mika Prunnila
- VTT
Technical Research Center of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland
- QTF
Centre of Excellence, Department of Applied Physics, Aalto University, Aalto FI-00076, Finland
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41
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Wang H, Li C, Fang P, Zhang Z, Zhang JZ. Synthesis, properties, and optoelectronic applications of two-dimensional MoS 2 and MoS 2-based heterostructures. Chem Soc Rev 2018; 47:6101-6127. [PMID: 30022215 DOI: 10.1039/c8cs00314a] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
As a two-dimensional (2D) material, molybdenum disulfide (MoS2) exhibits unique electronic and optical properties useful for a variety of optoelectronic applications including light harvesting. In this article, we review recent progress in the synthesis, properties and applications of MoS2 and related heterostructures. Heterostructured materials are developed to add more functionality or flexibility compared to single component materials. Our focus is on their novel properties and functionalities as well as emerging applications, especially in the areas of light energy harvesting or conversion. We highlight the correlation between structural properties and other properties including electronic, optical, and dynamic. Whenever appropriate, we also try to provide fundamental insight gained from experimental as well as theoretical studies. Finally, we discuss some current challenges and opportunities in technological applications of MoS2.
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Affiliation(s)
- Hongmei Wang
- College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, China.
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42
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Curtis JA, Burch AD, Barman B, Linn AG, McClintock LM, O'Beirne AL, Stiles MJ, Reno JL, McGill SA, Karaiskaj D, Hilton DJ. Broadband ultrafast terahertz spectroscopy in the 25 T Split Florida-Helix. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:073901. [PMID: 30068119 DOI: 10.1063/1.5023384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We describe the development of a broadband (0.3-10 THz) optical pump-terahertz probe spectrometer with an unprecedented combination of temporal resolution (≤200 fs) operating in external magnetic fields as high as 25 T using the new Split Florida-Helix magnet system. Using this new instrument, we measure the transient dynamics in a gallium arsenide four-quantum well sample after photoexcitation at 800 nm.
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Affiliation(s)
- Jeremy A Curtis
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Ashlyn D Burch
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Biplob Barman
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - A Garrison Linn
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Luke M McClintock
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Aidan L O'Beirne
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Matthew J Stiles
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - John L Reno
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Stephen A McGill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Denis Karaiskaj
- Department of Physics, University of South Florida, Tampa, Florida 33620, USA
| | - David J Hilton
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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43
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Zhao S, He D, He J, Zhang X, Yi L, Wang Y, Zhao H. Probing excitons in transition metal dichalcogenides by Drude-like exciton intraband absorption. NANOSCALE 2018; 10:9538-9546. [PMID: 29745949 DOI: 10.1039/c8nr03135e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding excitonic dynamics in two-dimensional semiconducting transition metal dichalcogenides is important for developing their optoelectronic applications. Recently, transient absorption techniques based on resonant excitonic absorption have been used to study various aspects of excitonic dynamics in these materials. The transient absorption in such measurements originates from phase-space state filling, bandgap renormalization, or screening effects. Here we report a new method to probe excitonic dynamics based on exciton intraband absorption. In this Drude-like process, probe photons are absorbed by excitons in their intraband excitation to higher energy states, causing a transient absorption signal. Although the magnitude of the transient absorption is lower than that of the resonant techniques, the new method is less restrictive on the selection of probe wavelength, has a larger linear range, and can provide complementary information on photocarrier dynamics. Using the WS2 monolayer and bulk samples as examples, we show that the new method can probe exciton-exciton annihilation at high densities and reveal exciton formation processes. We also found that the exciton intraband absorption cross section of the WS2 monolayer is on the order of 10-18 cm2.
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Affiliation(s)
- Siqi Zhao
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China.
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44
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Li Z, Zhang Y, Cheng C, Yu H, Chen F. 6.5 GHz Q-switched mode-locked waveguide lasers based on two-dimensional materials as saturable absorbers. OPTICS EXPRESS 2018; 26:11321-11330. [PMID: 29716055 DOI: 10.1364/oe.26.011321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/12/2018] [Indexed: 06/08/2023]
Abstract
Two-dimensional (2D) materials have generated great interest in the past few years opening up a new dimension in the development of optoelectronics and photonics. In this paper, we demonstrate 6.5 GHz fundamentally Q-switched mode-locked lasers with high performances in the femtosecond laser-written waveguide platform by applying graphene, MoS2 and Bi2Se3 as saturable absorbers (SAs). The minimum mode-locked pulse duration was measured to be as short as 26 ps in the case of Bi2Se3 SA. The maximum slope efficiency reached 53% in the case of MoS2 SA. This is the first demonstration of Q-switched mode-locked waveguide lasers based on MoS2 and Bi2Se3 in the waveguide platform. These high-performance Q-switched mode-locked waveguide lasers based on 2D materials pave the way for practical applications of compact ultrafast photonics.
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45
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Cattelan M, Fox NA. A Perspective on the Application of Spatially Resolved ARPES for 2D Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E284. [PMID: 29702567 PMCID: PMC5977298 DOI: 10.3390/nano8050284] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 12/13/2022]
Abstract
In this paper, a perspective on the application of Spatially- and Angle-Resolved PhotoEmission Spectroscopy (ARPES) for the study of two-dimensional (2D) materials is presented. ARPES allows the direct measurement of the electronic band structure of materials generating extremely useful insights into their electronic properties. The possibility to apply this technique to 2D materials is of paramount importance because these ultrathin layers are considered fundamental for future electronic, photonic and spintronic devices. In this review an overview of the technical aspects of spatially localized ARPES is given along with a description of the most advanced setups for laboratory and synchrotron-based equipment. This technique is sensitive to the lateral dimensions of the sample. Therefore, a discussion on the preparation methods of 2D material is presented. Some of the most interesting results obtained by ARPES are reported in three sections including: graphene, transition metal dichalcogenides (TMDCs) and 2D heterostructures. Graphene has played a key role in ARPES studies because it inspired the use of this technique with other 2D materials. TMDCs are presented for their peculiar transport, optical and spin properties. Finally, the section featuring heterostructures highlights a future direction for research into 2D material structures.
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Affiliation(s)
- Mattia Cattelan
- School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, UK; .
| | - Neil A Fox
- School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, UK; .
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK.
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46
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Hamann DM, Lygo AC, Esters M, Merrill DR, Ditto J, Sutherland DR, Bauers SR, Johnson DC. Structural Changes as a Function of Thickness in [(SnSe) 1+δ] mTiSe 2 Heterostructures. ACS NANO 2018; 12:1285-1295. [PMID: 29385326 DOI: 10.1021/acsnano.7b07506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Single- and few-layer metal chalcogenide compounds are of significant interest due to structural changes and emergent electronic properties on reducing dimensionality from three to two dimensions. To explore dimensionality effects in SnSe, a series of [(SnSe)1+δ]mTiSe2 intergrowth structures with increasing SnSe layer thickness (m = 1-4) were prepared from designed thin-film precursors. In-plane diffraction patterns indicated that significant structural changes occurred in the basal plane of the SnSe constituent as m is increased. Scanning transmission electron microscopy cross-sectional images of the m = 1 compound indicate long-range coherence between layers, whereas the m ≥ 2 compounds show extensive rotational disorder between the constituent layers. For m ≥ 2, the images of the SnSe constituent contain a variety of stacking sequences of SnSe bilayers. Density functional theory calculations suggest that the formation energy is similar for several different SnSe stacking sequences. The compounds show unexpected transport properties as m is increased, including the first p-type behavior observed in (MSe)m(TiSe2)n compounds. The resistivity of the m ≥ 2 compounds is larger than for m = 1, with m = 2 being the largest. At room temperature, the Hall coefficient is positive for m = 1 and negative for m = 2-4. The Hall coefficient of the m = 2 compound changes sign as temperature is decreased. The room-temperature Seebeck coefficient, however, switches from negative to positive at m = 3. These properties are incompatible with single band transport indicating that the compounds are not simple composites.
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Affiliation(s)
- Danielle M Hamann
- Department of Chemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States
| | - Alexander C Lygo
- Department of Chemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States
| | - Marco Esters
- Department of Chemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States
| | - Devin R Merrill
- Department of Chemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States
| | - Jeffrey Ditto
- Department of Chemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States
| | - Duncan R Sutherland
- Department of Chemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States
| | - Sage R Bauers
- Department of Chemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States
- National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - David C Johnson
- Department of Chemistry, Materials Science Institute, University of Oregon , Eugene, Oregon 97403, United States
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47
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Zhang J, Ouyang H, Zheng X, You J, Chen R, Zhou T, Sui Y, Liu Y, Cheng X, Jiang T. Ultrafast saturable absorption of MoS 2 nanosheets under different pulse-width excitation conditions. OPTICS LETTERS 2018; 43:243-246. [PMID: 29328250 DOI: 10.1364/ol.43.000243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
The newly raised two-dimensional material MoS2 is regarded as an ideal candidate for saturated absorbers. Here, the open-aperture Z-scan method is used to study the saturation absorption (SA) response of monolayer and multilayer MoS2, considering laser irradiation with different pulse widths. Specifically, in cases of 10 ns and 10 ps laser pulses, the accumulative nonlinearity [e.g., free carrier absorption (FCA)] coupled with SA is found in both monolayer and multilayer MoS2. However, under a 65 fs pulse laser, the instantaneous nonlinearity [e.g., two-photon absorption (TPA)] and the SA effect turn to play a significant role. Additionally, the saturation of both TPA and FCA is observed in MoS2. Importantly, the modulation depth of MoS2 shows different change trends by adjusting the laser pulse width.
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48
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Cunningham PD, Hanbicki AT, McCreary KM, Jonker BT. Photoinduced Bandgap Renormalization and Exciton Binding Energy Reduction in WS 2. ACS NANO 2017; 11:12601-12608. [PMID: 29227085 DOI: 10.1021/acsnano.7b06885] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Strong Coulomb attraction in monolayer transition metal dichalcogenides gives rise to tightly bound excitons and many-body interactions that dominate their optoelectronic properties. However, this Coulomb interaction can be screened through control of the surrounding dielectric environment as well as through applied voltage, which provides a potential means of tuning the bandgap, exciton binding energy, and emission wavelength. Here, we directly show that the bandgap and exciton binding energy can be optically tuned by means of the intensity of the incident light. Using transient absorption spectroscopy, we identify a sub-picosecond decay component in the excited-state dynamics of WS2 that emerges for incident photon energies above the A-exciton resonance, which originates from a nonequilibrium population of charge carriers that form excitons as they cool. The generation of this charge-carrier population exhibits two distinct energy thresholds. The higher threshold is coincident with the onset of continuum states and therefore provides a direct optical means of determining both the bandgap and exciton binding energy. Using this technique, we observe a reduction in the exciton binding energy from 310 ± 30 to 220 ± 20 meV as the excitation density is increased from 3 × 1011 to 1.2 × 1012 photons/cm2. This reduction is due to dynamic dipolar screening of Coulomb interactions by excitons, which is the underlying physical process that initiates bandgap renormalization and leads to the insulator-metal transition in monolayer transition metal dichalcogenides.
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Affiliation(s)
- Paul D Cunningham
- U.S. Naval Research Laboratory , Washington, DC 20375, United States
| | - Aubrey T Hanbicki
- U.S. Naval Research Laboratory , Washington, DC 20375, United States
| | | | - Berend T Jonker
- U.S. Naval Research Laboratory , Washington, DC 20375, United States
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49
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McKenna AJ, Eliason JK, Flannigan DJ. Spatiotemporal Evolution of Coherent Elastic Strain Waves in a Single MoS 2 Flake. NANO LETTERS 2017; 17:3952-3958. [PMID: 28510457 DOI: 10.1021/acs.nanolett.7b01565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We use bright-field imaging in an ultrafast electron microscope to spatiotemporally map the evolution of photoexcited coherent strain waves in a single, micrometer-size flake of MoS2. Following in situ femtosecond photoexcitation, we observe individual wave trains emerge from discrete nanoscale morphological features and propagate in-plane along specific wave vectors at approximately the speed of sound (7 nm/ps). Over the span of several hundred picoseconds, the 50 GHz wave trains (20 ps periods) are observed to undergo phonon-phonon scattering and wave-train interference, resulting in a transition to larger-scale, incoherent structural dynamics. This incoherent motion further evolves into coherent nanomechanical oscillations over a few nanoseconds, ultimately leading to megahertz, whole-flake multimode resonances having microsecond lifetimes. These results provide insight into the low-frequency structural response of MoS2 to relatively coherent optical photoexcitation by elucidating the origin and the evolution of high-velocity, gigahertz strain waves.
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Affiliation(s)
- Alyssa J McKenna
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Jeffrey K Eliason
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
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50
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Liu X, Guo Q, Qiu J. Emerging Low-Dimensional Materials for Nonlinear Optics and Ultrafast Photonics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1605886. [PMID: 28225160 DOI: 10.1002/adma.201605886] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/14/2016] [Indexed: 06/06/2023]
Abstract
Low-dimensional (LD) materials demonstrate intriguing optical properties, which lead to applications in diverse fields, such as photonics, biomedicine and energy. Due to modulation of electronic structure by the reduced structural dimensionality, LD versions of metal, semiconductor and topological insulators (TIs) at the same time bear distinct nonlinear optical (NLO) properties as compared with their bulk counterparts. Their interaction with short pulse laser excitation exhibits a strong nonlinear character manifested by NLO absorption, giving rise to optical limiting or saturated absorption associated with excited state absorption and Pauli blocking in different materials. In particular, the saturable absorption of these emerging LD materials including two-dimensional semiconductors as well as colloidal TI nanoparticles has recently been utilized for Q-switching and mode-locking ultra-short pulse generation across the visible, near infrared and middle infrared wavelength regions. Beside the large operation bandwidth, these ultrafast photonics applications are especially benefit from the high recovery rate as well as the facile processibility of these LD materials. The prominent NLO response of these LD materials have also provided new avenues for the development of novel NLO and photonics devices for all-optical control as well as optical circuits beyond ultrafast lasers.
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Affiliation(s)
- Xiaofeng Liu
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
- State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Qiangbing Guo
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
- State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Jianrong Qiu
- State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, 310027, P. R. China
- College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
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