1
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Sun X, Williams J, Sharma S, Kunjir S, Morris D, Zhao S, Ruan CY. Precision-controlled ultrafast electron microscope platforms. A case study: Multiple-order coherent phonon dynamics in 1T-TaSe 2 probed at 50 fs-10 fm scales. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2024; 11:024305. [PMID: 38566810 PMCID: PMC10987196 DOI: 10.1063/4.0000242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 03/08/2024] [Indexed: 04/04/2024]
Abstract
We report on the first detailed beam tests attesting the fundamental principle behind the development of high-current-efficiency ultrafast electron microscope systems where a radio frequency (RF) cavity is incorporated as a condenser lens in the beam delivery system. To allow for the experiment to be carried out with a sufficient resolution to probe the performance at the emittance floor, a new cascade loop RF controller system is developed to reduce the RF noise floor. Temporal resolution at 50 fs in full-width-at-half-maximum and detection sensitivity better than 1% are demonstrated on exfoliated 1T-TaSe2 system under a moderate repetition rate. To benchmark the performance, multi-terahertz edge-mode coherent phonon excitation is employed as the standard candle. The high temporal resolution and the significant visibility to very low dynamical contrast in diffraction signals via high-precision phase-space manipulation give strong support to the working principle for the new high-brightness femtosecond electron microscope systems.
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Affiliation(s)
- Xiaoyi Sun
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - Joseph Williams
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - Sachin Sharma
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - Shriraj Kunjir
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - Dan Morris
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - Shen Zhao
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - Chong-Yu Ruan
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
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2
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Tsai JY, Chen JY, Huang CW, Lo HY, Ke WE, Chu YH, Wu WW. A High-Entropy-Oxides-Based Memristor: Outstanding Resistive Switching Performance and Mechanisms in Atomic Structural Evolution. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2302979. [PMID: 37378645 DOI: 10.1002/adma.202302979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/11/2023] [Indexed: 06/29/2023]
Abstract
The application of high-entropy oxide (HEO) has attracted significant attention in recent years owing to their unique structural characteristics, such as excellent electrochemical properties and long-term cycling stability. However, the application of resistive random-access memory (RRAM) has not been extensively studied, and the switching mechanism of HEO-based RRAM has yet to be thoroughly investigated. In this study, HEO (Cr, Mn, Fe, Co, Ni)3 O4 with a spinel structure is epitaxially grown on a Nb:STO conductive substrate, and Pt metal is deposited as the top electrode. After the resistive-switching operation, some regions of the spinel structure are transformed into a rock-salt structure and analyzed using advanced transmission electron microscopy and scanning transmission electron microscopy. From the results of X-ray photoelectron spectroscopy and electron energy loss spectroscopy, only specific elements would change their valence state, which results in excellent resistive-switching properties with a high on/off ratio on the order of 105 , outstanding endurance (>4550 cycles), long retention time (>104 s), and high stability, which suggests that HEO is a promising RRAM material.
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Affiliation(s)
- Jing-Yuan Tsai
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Jui-Yuan Chen
- Department of Materials Science and Engineering, National United University, Miaoli, 360, Taiwan
| | - Chun-Wei Huang
- Department of Materials Science and Engineering, Feng Chia University, Taichung, 407, Taiwan
| | - Hung-Yang Lo
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Wei-En Ke
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Ying-Hao Chu
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, 300, Taiwan
| | - Wen-Wei Wu
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
- Center for the Intelligent Semiconductor Nano-system Technology Research, Hsinchu, 30078, Taiwan
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3
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Li D, Wei R, Sun F, Cheng Z, Yin H, Fan F, Wang X, Li C. Determining the Transformation Kinetics of Water Oxidation Intermediates on Hematite Photoanode. J Phys Chem Lett 2023; 14:8069-8076. [PMID: 37656051 DOI: 10.1021/acs.jpclett.3c02090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The oxygen evolution reaction (OER) from water is a sequential oxidation reaction process, involved in transformation of multiple reaction intermediates. For photo(electro)catalytic OER, revealing the intermediates transformation kinetics is quite challenging due to its coupling with photogenerated charge dynamics. Herein, we specifically study the transformation kinetics of the OER intermediates in rationally thin hematite photoanodes through increasing the ratio between surface intermediates and photogenerated charges in bulk. We directly identify the formation and consumption kinetics of one-hole OER intermediate (FeIV═O) in photoelectrochemical water oxidation using operando transient absorption (TA) spectroscopy. The microsecond formation kinetics of the FeIV═O species are sensitively changed by the excitation mode of Fe2O3. The subsecond consumption kinetics are closely dependent on surface FeIV═O species density, demonstrating that the cooperation of FeIV═O intermediates is the key to accelerating water oxidation kinetics on the Fe2O3 surface. This work provides insight into understanding and controlling water oxidation reaction kinetics on Fe2O3 surface.
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Affiliation(s)
- Dongfeng Li
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruifang Wei
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Fusai Sun
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zeyu Cheng
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Heng Yin
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China
| | - Fengtao Fan
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China
| | - Xiuli Wang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China
| | - Can Li
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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4
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Time-resolved transmission electron microscopy for nanoscale chemical dynamics. Nat Rev Chem 2023; 7:256-272. [PMID: 37117417 DOI: 10.1038/s41570-023-00469-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2023] [Indexed: 02/24/2023]
Abstract
The ability of transmission electron microscopy (TEM) to image a structure ranging from millimetres to Ångströms has made it an indispensable component of the toolkit of modern chemists. TEM has enabled unprecedented understanding of the atomic structures of materials and how structure relates to properties and functions. Recent developments in TEM have advanced the technique beyond static material characterization to probing structural evolution on the nanoscale in real time. Accompanying advances in data collection have pushed the temporal resolution into the microsecond regime with the use of direct-electron detectors and down to the femtosecond regime with pump-probe microscopy. Consequently, studies have deftly applied TEM for understanding nanoscale dynamics, often in operando. In this Review, time-resolved in situ TEM techniques and their applications for probing chemical and physical processes are discussed, along with emerging directions in the TEM field.
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5
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Li J, Chen H, Triana CA, Patzke GR. Hematite Photoanodes for Water Oxidation: Electronic Transitions, Carrier Dynamics, and Surface Energetics. Angew Chem Int Ed Engl 2021; 60:18380-18396. [PMID: 33761172 DOI: 10.1002/anie.202101783] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Indexed: 11/08/2022]
Abstract
We review the current understanding of charge carriers in model hematite photoanodes at different stages. The origin of charge carriers is discussed based on the electronic structure and absorption features, highlighting the controversial assignment of the electronic transitions near the absorption edge. Next, the dynamic evolution of charge carriers is analyzed both on the ultrafast and on the surface reaction timescales, with special emphasis on the arguable spectroscopic assignment of electrons/holes and their kinetics. Further, the competitive charge transfer centers at the solid-liquid interface are reviewed, and the chemical nature of relevant surface states is updated. Finally, an overview on the function of widely employed surface cocatalysts is given to illustrate the complex influence of physiochemical modifications on the charge carrier dynamics. The understanding of charge carriers from their origin all the way to their interfacial transfer is vital for the future of photoanode design.
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Affiliation(s)
- Jingguo Li
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Hang Chen
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Carlos A Triana
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Greta R Patzke
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
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6
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Li J, Chen H, Triana CA, Patzke GR. Hematite Photoanodes for Water Oxidation: Electronic Transitions, Carrier Dynamics, and Surface Energetics. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jingguo Li
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Hang Chen
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Carlos A. Triana
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Greta R. Patzke
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
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7
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Grave DA, Ellis DS, Piekner Y, Kölbach M, Dotan H, Kay A, Schnell P, van de Krol R, Abdi FF, Friedrich D, Rothschild A. Extraction of mobile charge carrier photogeneration yield spectrum of ultrathin-film metal oxide photoanodes for solar water splitting. NATURE MATERIALS 2021; 20:833-840. [PMID: 33875852 DOI: 10.1038/s41563-021-00955-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/10/2021] [Indexed: 06/12/2023]
Abstract
Light absorption in strongly correlated electron materials can excite electrons and holes into a variety of different states. Some of these excitations yield mobile charge carriers, whereas others result in localized states that cannot contribute to photocurrent. The photogeneration yield spectrum, ξ(λ), represents the wavelength-dependent ratio between the contributing absorption that ultimately generates mobile charge carriers and the overall absorption. Despite being a vital material property, it is not trivial to characterize. Here, we present an empirical method to extract ξ(λ) through optical and external quantum efficiency measurements of ultrathin films. We applied this method to haematite photoanodes for water photo-oxidation, and observed that it is self-consistent for different illumination conditions and applied potentials. We found agreement between the extracted ξ(λ) spectrum and the photoconductivity spectrum measured by time-resolved microwave conductivity. These measurements revealed that mobile charge carrier generation increases with increasing energy across haematite's absorption spectrum. Low-energy non-contributing absorption fundamentally limits the photoconversion efficiency of haematite photoanodes and provides an upper limit to the achievable photocurrent that is substantially lower than that predicted based solely on absorption above the bandgap. We extended our analysis to TiO2 and BiVO4 photoanodes, demonstrating the broader utility of the method for determining ξ(λ).
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Affiliation(s)
- Daniel A Grave
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, Israel.
- Department of Materials Engineering and Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be'er Sheva, Israel.
| | - David S Ellis
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | - Yifat Piekner
- The Nancy & Stephen Grand Technion Energy Program (GTEP), Technion - Israel Institute of Technology, Haifa, Israel
| | - Moritz Kölbach
- Institute for Solar Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Hen Dotan
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | - Asaf Kay
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | - Patrick Schnell
- Institute for Solar Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Roel van de Krol
- Institute for Solar Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Fatwa F Abdi
- Institute for Solar Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Dennis Friedrich
- Institute for Solar Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Avner Rothschild
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, Israel.
- The Nancy & Stephen Grand Technion Energy Program (GTEP), Technion - Israel Institute of Technology, Haifa, Israel.
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8
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Zhang Z, Karimata I, Nagashima H, Muto S, Ohara K, Sugimoto K, Tachikawa T. Interfacial oxygen vacancies yielding long-lived holes in hematite mesocrystal-based photoanodes. Nat Commun 2019; 10:4832. [PMID: 31645549 PMCID: PMC6811569 DOI: 10.1038/s41467-019-12581-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 09/18/2019] [Indexed: 01/28/2023] Open
Abstract
Hematite (α-Fe2O3) is one of the most promising candidates as a photoanode materials for solar water splitting. Owing to the difficulty in suppressing the significant charge recombination, however, the photoelectrochemical (PEC) conversion efficiency of hematite is still far below the theoretical limit. Here we report thick hematite films (∼1500 nm) constructed by highly ordered and intimately attached hematite mesocrystals (MCs) for highly efficient PEC water oxidation. Due to the formation of abundant interfacial oxygen vacancies yielding a high carrier density of ∼1020 cm-3 and the resulting extremely large proportion of depletion regions with short depletion widths (<10 nm) in hierarchical structures, charge separation and collection efficiencies could be markedly improved. Moreover, it was found that long-lived charges are generated via excitation by shorter wavelength light (below ∼500 nm), thus enabling long-range hole transfer through the MC network to drive high efficiency of light-to-energy conversion under back illumination.
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Affiliation(s)
- Zhujun Zhang
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Izuru Karimata
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Hiroki Nagashima
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Shunsuke Muto
- Electron Nanoscopy Section, Advanced Measurement Technology Center, Institute of Materials and Systems for Sustainability, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - Koji Ohara
- Diffraction and Scattering Division, Center for Synchrotron Radiation, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Kunihisa Sugimoto
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
- Diffraction and Scattering Division, Center for Synchrotron Radiation, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida-Ushinomiya-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Takashi Tachikawa
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
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9
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Grave DA, Yatom N, Ellis DS, Toroker MC, Rothschild A. The "Rust" Challenge: On the Correlations between Electronic Structure, Excited State Dynamics, and Photoelectrochemical Performance of Hematite Photoanodes for Solar Water Splitting. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706577. [PMID: 29504160 DOI: 10.1002/adma.201706577] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 12/31/2017] [Indexed: 06/08/2023]
Abstract
In recent years, hematite's potential as a photoanode material for solar hydrogen production has ignited a renewed interest in its physical and interfacial properties, which continues to be an active field of research. Research on hematite photoanodes provides new insights on the correlations between electronic structure, transport properties, excited state dynamics, and charge transfer phenomena, and expands our knowledge on solar cell materials into correlated electron systems. This research news article presents a snapshot of selected theoretical and experimental developments linking the electronic structure to the photoelectrochemical performance, with particular focus on optoelectronic properties and charge carrier dynamics.
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Affiliation(s)
- Daniel A Grave
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Natav Yatom
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - David S Ellis
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Maytal Caspary Toroker
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - Avner Rothschild
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
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10
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Biswas S, Husek J, Londo S, Baker LR. Highly Localized Charge Transfer Excitons in Metal Oxide Semiconductors. NANO LETTERS 2018; 18:1228-1233. [PMID: 29368513 DOI: 10.1021/acs.nanolett.7b04818] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The ability to observe charge localization in photocatalytic materials on the ultrafast time scale promises to reveal important correlations between excited state electronic structure and photochemical energy conversion. Of particular interest is the ability to determine hole localization in the hybridized valence band of transition metal oxide semiconductors. Using femtosecond extreme ultraviolet reflection absorption (XUV-RA) spectroscopy we directly observe the formation of photoexcited electrons and holes in Fe2O3, Co3O4, and NiO occurring within the 100 fs instrument response. In each material, holes localize to the O 2p valence band states as probed at the O L1-edge, while electrons localize to metal 3d conduction band states on this same time scale as probed at the metal M2,3-edge. Chemical shifts at the O L1-edge enable unambiguous comparison of metal-oxygen (M-O) bond covalency. Pump flux dependent measurements show that the exciton radius is on the order of a single M-O bond length, revealing a highly localized nature of exciton in each metal oxide studied.
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Affiliation(s)
- Somnath Biswas
- Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States
| | - Jakub Husek
- Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States
| | - Stephen Londo
- Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States
| | - L Robert Baker
- Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States
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11
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Biswas S, Husek J, Baker LR. Elucidating ultrafast electron dynamics at surfaces using extreme ultraviolet (XUV) reflection–absorption spectroscopy. Chem Commun (Camb) 2018; 54:4216-4230. [DOI: 10.1039/c8cc01745j] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Time-resolved XUV reflection–absorption spectroscopy probes core-to-valence transitions to reveal state-specific electron dynamics at surfaces.
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12
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Williams J, Zhou F, Sun T, Tao Z, Chang K, Makino K, Berz M, Duxbury PM, Ruan CY. Active control of bright electron beams with RF optics for femtosecond microscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:044035. [PMID: 28868325 PMCID: PMC5565489 DOI: 10.1063/1.4999456] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 08/08/2017] [Indexed: 06/07/2023]
Abstract
A frontier challenge in implementing femtosecond electron microscopy is to gain precise optical control of intense beams to mitigate collective space charge effects for significantly improving the throughput. Here, we explore the flexible uses of an RF cavity as a longitudinal lens in a high-intensity beam column for condensing the electron beams both temporally and spectrally, relevant to the design of ultrafast electron microscopy. Through the introduction of a novel atomic grating approach for characterization of electron bunch phase space and control optics, we elucidate the principles for predicting and controlling the phase space dynamics to reach optimal compressions at various electron densities and generating conditions. We provide strategies to identify high-brightness modes, achieving ∼100 fs and ∼1 eV resolutions with 106 electrons per bunch, and establish the scaling of performance for different bunch charges. These results benchmark the sensitivity and resolution from the fundamental beam brightness perspective and also validate the adaptive optics concept to enable delicate control of the density-dependent phase space structures to optimize the performance, including delivering ultrashort, monochromatic, high-dose, or coherent electron bunches.
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Affiliation(s)
- J Williams
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
| | - F Zhou
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
| | - T Sun
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
| | - Z Tao
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
| | - K Chang
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
| | - K Makino
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
| | - M Berz
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
| | - P M Duxbury
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
| | - C-Y Ruan
- Department of Physics and Astronomy, East Lansing, Michigan 48824, USA
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