1
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Perez C, Ellis SR, Alcorn FM, Smoll EJ, Fuller EJ, Leonard F, Chandler D, Talin AA, Bisht RS, Ramanathan S, Goodson KE, Kumar S. Picosecond carrier dynamics in InAs and GaAs revealed by ultrafast electron microscopy. SCIENCE ADVANCES 2024; 10:eadn8980. [PMID: 38748793 PMCID: PMC11095486 DOI: 10.1126/sciadv.adn8980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/10/2024] [Indexed: 05/19/2024]
Abstract
Understanding the limits of spatiotemporal carrier dynamics, especially in III-V semiconductors, is key to designing ultrafast and ultrasmall optoelectronic components. However, identifying such limits and the properties controlling them has been elusive. Here, using scanning ultrafast electron microscopy, in bulk n-GaAs and p-InAs, we simultaneously measure picosecond carrier dynamics along with three related quantities: subsurface band bending, above-surface vacuum potentials, and surface trap densities. We make two unexpected observations. First, we uncover a negative-time contrast in secondary electrons resulting from an interplay among these quantities. Second, despite dopant concentrations and surface state densities differing by many orders of magnitude between the two materials, their carrier dynamics, measured by photoexcited band bending and filling of surface states, occur at a seemingly common timescale of about 100 ps. This observation may indicate fundamental kinetic limits tied to a multitude of material and surface properties of optoelectronic III-V semiconductors and highlights the need for techniques that simultaneously measure electro-optical kinetic properties.
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Affiliation(s)
- Christopher Perez
- Sandia National Laboratories, Livermore, CA, USA
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Scott R. Ellis
- Sandia National Laboratories, Livermore, CA, USA
- Intel Corporation, San Jose, CA, USA
| | | | | | | | | | | | | | - Ravindra Singh Bisht
- Department of Electrical and Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Shriram Ramanathan
- Department of Electrical and Computer Engineering, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Kenneth E. Goodson
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Suhas Kumar
- Sandia National Laboratories, Livermore, CA, USA
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2
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Roy Moulik S, Lai Y, Amini A, Soucy P, Beyerlein KR, Liang J. Spatial-temporal characterization of photoemission in a streak-mode dynamic transmission electron microscope. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2024; 11:014303. [PMID: 38406321 PMCID: PMC10894042 DOI: 10.1063/4.0000219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/28/2024] [Indexed: 02/27/2024]
Abstract
A long-standing motivation driving high-speed electron microscopy development is to capture phase transformations and material dynamics in real time with high spatial and temporal resolution. Current dynamic transmission electron microscopes (DTEMs) are limited to nanosecond temporal resolution and the ability to capture only a few frames of a transient event. With the motivation to overcome these limitations, we present our progress in developing a streak-mode DTEM (SM-DTEM) and demonstrate the recovery of picosecond images with high frame sequence depth. We first demonstrate that a zero-dimensional (0D) SM-DTEM can provide temporal information on any local region of interest with a 0.37 μm diameter, a 20-GHz sampling rate, and 1200 data points in the recorded trace. We use this method to characterize the temporal profile of the photoemitted electron pulse, finding that it deviates from the incident ultraviolet laser pulse and contains an unexpected peak near its onset. Then, we demonstrate a two-dimensional (2D) SM-DTEM, which uses compressed-sensing-based tomographic imaging to recover a full spatiotemporal photoemission profile over a 1.85-μm-diameter field of view with nanoscale spatial resolution, 370-ps inter-frame interval, and 140-frame sequence depth in a 50-ns time window. Finally, a perspective is given on the instrumental modifications necessary to further develop this promising technique with the goal of decreasing the time to capture a 2D SM-DTEM dataset.
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Affiliation(s)
- Samik Roy Moulik
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X1P7, Canada
| | - Yingming Lai
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X1P7, Canada
| | - Aida Amini
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X1P7, Canada
| | - Patrick Soucy
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X1P7, Canada
| | - Kenneth R. Beyerlein
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X1P7, Canada
| | - Jinyang Liang
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X1P7, Canada
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3
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Prasad AK, Šebesta J, Esteban-Puyuelo R, Maldonado P, Ji S, Sanyal B, Grånäs O, Weissenrieder J. Nonequilibrium Phonon Dynamics and Its Impact on the Thermal Conductivity of the Benchmark Thermoelectric Material SnSe. ACS NANO 2023; 17:21006-21017. [PMID: 37862596 PMCID: PMC10655201 DOI: 10.1021/acsnano.3c03827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Thermoelectric materials play a vital role in the pursuit of a sustainable energy system by allowing the conversion of waste heat to electric energy. Low thermal conductivity is essential to achieving high-efficiency conversion. The conductivity depends on an interplay between the phononic and electronic properties of the nonequilibrium state. Therefore, obtaining a comprehensive understanding of nonequilibrium dynamics of the electronic and phononic subsystems as well as their interactions is key for unlocking the microscopic mechanisms that ultimately govern thermal conductivity. A benchmark material that exhibits ultralow thermal conductivity is SnSe. We study the nonequilibrium phonon dynamics induced by an excited electron population using a framework combining ultrafast electron diffuse scattering and nonequilibrium kinetic theory. This in-depth approach provides a fundamental understanding of energy transfer in the spatiotemporal domain. Our analysis explains the dynamics leading to the observed low thermal conductivity, which we attribute to a mode-dependent tendency to nonconservative phonon scattering. The results offer a penetrating perspective on energy transport in condensed matter with far-reaching implications for rational design of advanced materials with tailored thermal properties.
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Affiliation(s)
- Amit Kumar Prasad
- Materials and Nano Physics, School of Engineering Sciences, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Jakub Šebesta
- Materials Theory, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Raquel Esteban-Puyuelo
- Materials Theory, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Pablo Maldonado
- Materials Theory, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Shaozheng Ji
- Materials and Nano Physics, School of Engineering Sciences, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Biplab Sanyal
- Materials Theory, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Oscar Grånäs
- Materials Theory, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
| | - Jonas Weissenrieder
- Materials and Nano Physics, School of Engineering Sciences, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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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: 5] [Impact Index Per Article: 5.0] [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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Kim YJ, Nho HW, Ji S, Lee H, Ko H, Weissenrieder J, Kwon OH. Femtosecond-resolved imaging of a single-particle phase transition in energy-filtered ultrafast electron microscopy. SCIENCE ADVANCES 2023; 9:eadd5375. [PMID: 36706188 PMCID: PMC9882981 DOI: 10.1126/sciadv.add5375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/20/2022] [Indexed: 06/18/2023]
Abstract
Using an energy filter in transmission electron microscopy has enabled elemental mapping at the atomic scale and improved the precision of structural determination by gating inelastic and elastic imaging electrons, respectively. Here, we use an energy filter in ultrafast electron microscopy to enhance the temporal resolution toward the domain of atomic motion. Visualizing transient structures with femtosecond temporal precision was achieved by selecting imaging electrons in a narrow energy distribution from dense chirped photoelectron packets with broad longitudinal momentum distributions and thus typically exhibiting picosecond durations. In this study, the heterogeneous ultrafast phase transitions of vanadium dioxide (VO2) nanoparticles, a representative strongly correlated system, were filmed and attributed to the emergence of a transient, low-symmetry metallic phase caused by different local strains. Our approach enables electron microscopy to access the time scale of elementary nuclear motion to visualize the onset of the structural dynamics of matter at the nanoscale.
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Affiliation(s)
- Ye-Jin Kim
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
- Center for Soft and Living Matter, Institute for Basic Science, 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Hak-Won Nho
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
- Center for Soft and Living Matter, Institute for Basic Science, 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Shaozheng Ji
- Materials and Nano Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm SE-100 44, Sweden
| | - Hyejin Lee
- School of Energy and Chemical Engineering, UNIST, 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Hyunhyub Ko
- School of Energy and Chemical Engineering, UNIST, 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Jonas Weissenrieder
- Materials and Nano Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm SE-100 44, Sweden
| | - Oh-Hoon Kwon
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
- Center for Soft and Living Matter, Institute for Basic Science, 50 UNIST-gil, Ulsan 44919, Republic of Korea
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6
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Picher M, Sinha SK, LaGrange T, Banhart F. Analytics at the nanometer and nanosecond scales by short electron pulses in an electron microscope. CHEMTEXTS 2022. [DOI: 10.1007/s40828-022-00169-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Curtis WA, Willis SA, Flannigan DJ. Single-photoelectron collection efficiency in 4D ultrafast electron microscopy. Phys Chem Chem Phys 2022; 24:14044-14054. [PMID: 35640169 DOI: 10.1039/d2cp01250b] [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
In femtosecond (fs) 4D ultrafast electron microscopy (UEM), a tradeoff is made between photoelectrons per packet and time resolution. One consequence of this can be longer-than-desirable acquisition times for low-density packets, and particularly for low repetition rates when complete photothermal dissipation is required. Thus, gaining an understanding of photoelectron trajectories in the gun region is important for identifying factors that limit collection efficiency (CE; fraction of photoelectrons that enter the illumination system). Here, we continue our work on the systematic study of photoelectron trajectories in the gun region of a Thermo Fisher/FEI Tecnai Femto UEM, focusing specifically on CE in the single-electron regime. Using General Particle Tracer, calculated field maps, and the exact architecture of the Tecnai Femto UEM, we simulated the effects of fs laser parameters and key gun elements on CE. The results indicate CE strongly depends upon the laser spot size on the source, the (unbiased) Wehnelt aperture diameter, and the incident photon energy. The CE dispersion with laser spot size is found to be strongly dependent on aperture diameter, being nearly dispersionless for the largest apertures. A gun crossover is also observed, with the beam-waist position being dependent on the aperture diameter, further illustrating that the Wehnelt aperture acts as a simple, fixed electrostatic lens in UEM mode. This work provides further insights into the operational aspects of fs 4D UEM.
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Affiliation(s)
- Wyatt A Curtis
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN 55455, USA. .,Minnesota Institute for Ultrafast Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - Simon A Willis
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN 55455, USA. .,Minnesota Institute for Ultrafast Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN 55455, USA. .,Minnesota Institute for Ultrafast Science, University of Minnesota, Minneapolis, MN 55455, USA
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8
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Stroboscopic ultrafast imaging using RF strip-lines in a commercial transmission electron microscope. Ultramicroscopy 2022; 235:113497. [DOI: 10.1016/j.ultramic.2022.113497] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 02/09/2022] [Accepted: 02/15/2022] [Indexed: 11/18/2022]
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9
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Curtis WA, Flannigan DJ. Toward Å-fs-meV resolution in electron microscopy: systematic simulation of the temporal spread of single-electron packets. Phys Chem Chem Phys 2021; 23:23544-23553. [PMID: 34648611 DOI: 10.1039/d1cp03518e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Though efforts to improve the temporal resolution of transmission electron microscopes (TEMs) have waxed and waned for decades, with relatively recent advances routinely reaching sub-picosecond scales, fundamental and practical challenges have hindered the advance of combined Å-fs-meV resolutions, particularly for core-loss spectroscopy and real-space imaging. This is due in no small part to the complexity of the approach required to access timescales upon which electrons, atoms, molecules, and materials first begin to respond and transform - attoseconds to picoseconds. Here we present part of a larger effort devoted to systematically mapping the instrument parameter space of a TEM modified to reach ultrafast timescales. With General Particle Tracer, we studied the statistical temporal distributions of single-electron packets as a function of various fs pulsed-laser parameters and electron-gun configurations and fields for the exact architecture and dimensions of a Thermo Fisher Tecnai Femto ultrafast electron microscope. We focused on easily-adjustable parameters, such as laser pulse duration, laser spot size, photon energy, Wehnelt aperture diameter, and photocathode size. In addition to establishing trends and dispersion behaviors, we identify regimes within which packet duration can be 100s of fs and approach the 300 fs laser limit employed here. Overall, the results provide a detailed picture of the temporal behavior of single-electron packets in the Tecnai Femto gun region, forming the initial contribution of a larger effort.
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Affiliation(s)
- Wyatt A Curtis
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN, 55455, USA.
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN, 55455, USA.
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10
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Aseev SA, Mironov BN, Ryabov EA, Avilov AS, Girichev GV, Ischenko AA. Ultrafast Electron Microscopy: An Instrument of the XXI Century. CRYSTALLOGR REP+ 2021. [DOI: 10.1134/s1063774521040040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Di Giulio V, Kfir O, Ropers C, García de Abajo FJ. Modulation of Cathodoluminescence Emission by Interference with External Light. ACS NANO 2021; 15:7290-7304. [PMID: 33724007 PMCID: PMC8939848 DOI: 10.1021/acsnano.1c00549] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/18/2021] [Indexed: 05/20/2023]
Abstract
Spontaneous processes triggered in a sample by free electrons, such as cathodoluminescence, are commonly regarded and detected as stochastic events. Here, we supplement this picture by showing through first-principles theory that light and free-electron pulses can interfere when interacting with a nanostructure, giving rise to a modulation in the spectral distribution of the cathodoluminescence light emission that is strongly dependent on the electron wave function. Specifically, for a temporally focused electron, cathodoluminescence can be canceled upon illumination with a spectrally modulated dimmed laser that is phase-locked relative to the electron density profile. We illustrate this idea with realistic simulations under attainable conditions in currently available ultrafast electron microscopes. We further argue that the interference between excitations produced by light and free electrons enables the manipulation of the ultrafast materials response by combining the spectral and temporal selectivity of the light with the atomic resolution of electron beams.
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Affiliation(s)
- Valerio Di Giulio
- ICFO-Institut de
Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Ofer Kfir
- IV Physical Institute,
Solids and Nanostructures, University of
Göttingen, 37077 Göttingen, Germany
- Max Planck
Institute for Biophysical Chemistry (MPIBPC), 37077 Göttingen, Germany
| | - Claus Ropers
- IV Physical Institute,
Solids and Nanostructures, University of
Göttingen, 37077 Göttingen, Germany
- Max Planck
Institute for Biophysical Chemistry (MPIBPC), 37077 Göttingen, Germany
| | - F. Javier García de Abajo
- ICFO-Institut de
Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis
Avançats, Passeig
Lluís Companys 23, 08010 Barcelona, Spain
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12
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García
de Abajo FJ, Di Giulio V. Optical Excitations with Electron Beams: Challenges and Opportunities. ACS PHOTONICS 2021; 8:945-974. [PMID: 35356759 PMCID: PMC8939335 DOI: 10.1021/acsphotonics.0c01950] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 05/20/2023]
Abstract
Free electron beams such as those employed in electron microscopes have evolved into powerful tools to investigate photonic nanostructures with an unrivaled combination of spatial and spectral precision through the analysis of electron energy losses and cathodoluminescence light emission. In combination with ultrafast optics, the emerging field of ultrafast electron microscopy utilizes synchronized femtosecond electron and light pulses that are aimed at the sampled structures, holding the promise to bring simultaneous sub-Å-sub-fs-sub-meV space-time-energy resolution to the study of material and optical-field dynamics. In addition, these advances enable the manipulation of the wave function of individual free electrons in unprecedented ways, opening sound prospects to probe and control quantum excitations at the nanoscale. Here, we provide an overview of photonics research based on free electrons, supplemented by original theoretical insights and discussion of several stimulating challenges and opportunities. In particular, we show that the excitation probability by a single electron is independent of its wave function, apart from a classical average over the transverse beam density profile, whereas the probability for two or more modulated electrons depends on their relative spatial arrangement, thus reflecting the quantum nature of their interactions. We derive first-principles analytical expressions that embody these results and have general validity for arbitrarily shaped electrons and any type of electron-sample interaction. We conclude with some perspectives on various exciting directions that include disruptive approaches to noninvasive spectroscopy and microscopy, the possibility of sampling the nonlinear optical response at the nanoscale, the manipulation of the density matrices associated with free electrons and optical sample modes, and appealing applications in optical modulation of electron beams, all of which could potentially revolutionize the use of free electrons in photonics.
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Affiliation(s)
- F. Javier García
de Abajo
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
- E-mail:
| | - Valerio Di Giulio
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels, Barcelona, Spain
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13
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Ponce A, Aguilar JA, Tate J, Yacamán MJ. Advances in the electron diffraction characterization of atomic clusters and nanoparticles. NANOSCALE ADVANCES 2021; 3:311-325. [PMID: 36131739 PMCID: PMC9417509 DOI: 10.1039/d0na00590h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/15/2020] [Indexed: 06/15/2023]
Abstract
Nanoparticles and metallic clusters continue to make a remarkable impact on novel and emerging technologies. In recent years, there have been impressive advances in the controlled synthesis of clusters and their advanced characterization. One of the most common ways to determine the structures of nanoparticles and clusters is by means of X-ray diffraction methods. However, this requires the clusters to crystallize in a similar way to those used in protein studies, which is not possible in many cases. Novel methods based on electron diffraction have been used to efficiently study individual nanoparticles and clusters and these can overcome the obstacles commonly encountered during X-ray diffraction methods without the need for large crystals. These novel methodologies have improved with advances in electron microscopy instrumentation and electron detection. Here, we review advanced methodologies for characterizing metallic nanoparticles and clusters using a variety of electron diffraction procedures. These include selected area electron diffraction, nanobeam diffraction, coherent electron diffraction, precession electron diffraction, scanning transmission electron microcopy diffraction, and high throughput data analytics, which leverage deep learning to reduce the propensity for data errors and translate nanometer and atomic scale measurements into material data.
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Affiliation(s)
- Arturo Ponce
- Department of Physics and Astronomy, The University of Texas at San Antonio San Antonio Texas 78249 USA
| | - Jeffery A Aguilar
- Idaho National Laboratory, Nuclear Science and Technology Division Idaho Falls Idaho 83415 USA
- Lockheed Martin Space, Advanced Technology Center Palo Alto California 94304 USA
| | - Jess Tate
- University of Utah, Scientific Computing Imaging Institute, Department of Electrical and Computer Engineering Salt Lake City Utah USA
| | - Miguel José Yacamán
- Department of Applied Physics and Materials Science, Center for Materials Interfaces in Research and Applications, Northern Arizona University Flagstaff AZ USA
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14
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Danz T, Domröse T, Ropers C. Ultrafast nanoimaging of the order parameter in a structural phase transition. Science 2021; 371:371-374. [DOI: 10.1126/science.abd2774] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 12/11/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Thomas Danz
- 4th Physical Institute – Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - Till Domröse
- 4th Physical Institute – Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
| | - Claus Ropers
- 4th Physical Institute – Solids and Nanostructures, University of Göttingen, 37077 Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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15
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Abstract
Time-resolved electron microscopy is based on the excitation of a sample by pulsed laser radiation and its probing by synchronized photoelectron bunches in the electron microscope column. With femtosecond lasers, if probing pulses with a small number of electrons—in the limit, single-electron wave packets—are used, the stroboscopic regime enables ultrahigh spatiotemporal resolution to be obtained, which is not restricted by the Coulomb repulsion of electrons. This review article presents the current state of the ultrafast electron microscopy (UEM) method for detecting the structural dynamics of matter in the time range from picoseconds to attoseconds. Moreover, in the imaging mode, the spatial resolution lies, at best, in the subnanometer range, which limits the range of observation of structural changes in the sample. The ultrafast electron diffraction (UED), which created the methodological basis for the development of UEM, has opened the possibility of creating molecular movies that show the behavior of the investigated quantum system in the space-time continuum with details of sub-Å spatial resolution. Therefore, this review on the development of UEM begins with a description of the main achievements of UED, which formed the basis for the creation and further development of the UEM method. A number of recent experiments are presented to illustrate the potential of the UEM method.
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16
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Zhao J, Bakr OM, Mohammed OF. Ultrafast electron imaging of surface charge carrier dynamics at low voltage. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:021001. [PMID: 32266302 PMCID: PMC7105398 DOI: 10.1063/4.0000007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 03/10/2020] [Indexed: 06/11/2023]
Abstract
The performance of optoelectronic devices strongly depends on charge carrier dynamics on top of surfaces of the absorber layers. Unfortunately, this information cannot be selectively probed using conventional ultrafast laser spectroscopic methods, due to the large penetration depth (tens of nm to μm) of the photon pulses in the pump-probe configurations. Therefore, ultrafast time-resolved approaches that can directly and selectively visualize the behavior of the surface carrier dynamics are urgently needed. Here, we introduce a novel methodology of low-voltage scanning ultrafast electron microscopy that can take ultrafast time-resolved images (snapshots) of the surface of materials at the sub-nanometer level. By this approach, the surface of the photoactive materials is optically excited and imaged, using a pulsed low-voltage electron beam (1 keV) that interacts with the surface to generate secondary electrons with an energy of a few eV, and that are emitted only from the top surface of materials, providing direct information about the carrier dynamics and the localization of electron/holes in real space and time. An outlook on the potential applications of this low voltage approach in different disciplines will also be discussed.
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Affiliation(s)
- Jianfeng Zhao
- Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Osman M Bakr
- Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Omar F Mohammed
- Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
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17
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Gaulandris F, Simonsen SB, Wagner JB, Mølhave K, Muto S, Kuhn LT. Methods for Calibration of Specimen Temperature During In Situ Transmission Electron Microscopy Experiments. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:3-17. [PMID: 31957636 DOI: 10.1017/s1431927619015344] [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
One of the biggest challenges for in situ heating transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) is the ability to measure the local temperature of the specimen accurately. Despite technological improvements in the construction of TEM/STEM heating holders, the problem of being able to measure the real sample temperature is still the subject of considerable discussion. In this study, we review the present literature on methodologies for temperature calibration. We analyze calibration methods that require the use of a thermometric material in addition to the specimen under study, as well as methods that can be performed directly on the specimen of interest without the need for a previous calibration. Finally, an overview of the most important characteristics of all the treated techniques, including temperature ranges and uncertainties, is provided in order to provide an accessory database to consult before an in situ TEM/STEM temperature calibration experiment.
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Affiliation(s)
- Fabrizio Gaulandris
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby, Denmak
| | - Søren B Simonsen
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby, Denmak
| | - Jakob B Wagner
- DTU Nanolab, Technical University of Denmark, Fysikvej DK-2800 Kgs. Lyngby, Denmark
| | - Kristian Mølhave
- DTU Nanolab, Technical University of Denmark, Fysikvej DK-2800 Kgs. Lyngby, Denmark
| | - Shun Muto
- Institute of Materials and Systems for Sustainability, Nagoya University, 464-8601 Furocho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Luise T Kuhn
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej, DK-2800 Kgs. Lyngby, Denmak
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18
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Isik T, Xu X, Son SF, Gunduz IE, Ortalan V. Investigation of Polymer Matrix Nano‐Aluminum Composites with Pulsed Laser Heating by In‐Situ TEM. PROPELLANTS EXPLOSIVES PYROTECHNICS 2019. [DOI: 10.1002/prep.201900134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Tugba Isik
- School of Mechanical EngineeringPurdue University West Lafayette, IN USA
- Institute of Materials ScienceUniversity of Connecticut Storrs, CT USA
| | - Xiaohui Xu
- School of Materials Science and EngineeringPurdue University West Lafayette, IN USA
| | - Steven F. Son
- School of Mechanical EngineeringPurdue University West Lafayette, IN USA
| | - I. Emre Gunduz
- Mechanical and Aerospace Engineering DepartmentNaval Postgraduate School Monterey, CA USA
| | - Volkan Ortalan
- Institute of Materials ScienceUniversity of Connecticut Storrs, CT USA
- Materials Science and EngineeringUniversity of Connecticut Storrs, CT USA
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19
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Verhoeven W, van Rens JFM, Kemper AH, Rietman EH, van Doorn HA, Koole I, Kieft ER, Mutsaers PHA, Luiten OJ. Design and characterization of dielectric filled TM 110 microwave cavities for ultrafast electron microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:083703. [PMID: 31472630 DOI: 10.1063/1.5080003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 08/04/2019] [Indexed: 06/10/2023]
Abstract
Microwave cavities oscillating in the TM110 mode can be used as dynamic electron-optical elements inside an electron microscope. By filling the cavity with a dielectric material, it becomes more compact and power efficient, facilitating the implementation in an electron microscope. However, the incorporation of the dielectric material makes the manufacturing process more difficult. Presented here are the steps taken to characterize the dielectric material and to reproducibly fabricate dielectric filled cavities. Also presented are two versions with improved capabilities. The first, called a dual-mode cavity, is designed to support two modes simultaneously. The second has been optimized for low power consumption. With this optimized cavity, a magnetic field strength of 2.84 ± 0.07 mT was generated at an input power of 14.2 ± 0.2 W. Due to the low input powers and small dimensions, these dielectric cavities are ideal as electron-optical elements for electron microscopy setups.
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Affiliation(s)
- W Verhoeven
- Department of Applied Physics, Coherence and Quantum Technology Group, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - J F M van Rens
- Department of Applied Physics, Coherence and Quantum Technology Group, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - A H Kemper
- Department of Applied Physics, Coherence and Quantum Technology Group, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - E H Rietman
- Department of Applied Physics, Coherence and Quantum Technology Group, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - H A van Doorn
- Department of Applied Physics, Coherence and Quantum Technology Group, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - I Koole
- Department of Applied Physics, Coherence and Quantum Technology Group, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - E R Kieft
- Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands
| | - P H A Mutsaers
- Department of Applied Physics, Coherence and Quantum Technology Group, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - O J Luiten
- Department of Applied Physics, Coherence and Quantum Technology Group, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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20
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Xu X, Isik T, Kundu S, Ortalan V. Investigation of laser-induced inter-welding between Au and Ag nanoparticles and the plasmonic properties of welded dimers. NANOSCALE 2018; 10:23050-23058. [PMID: 30511072 DOI: 10.1039/c8nr07718e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Noble metallic nanoparticles with unique plasmonic properties are useful in a variety of applications including bio-imaging, sensing, cancer therapy, etc. The properties of metallic nanoparticles can be tuned in multiple ways, among which laser welding is a highly efficient method. In this study, laser-induced inter-welding of Ag-Au nanoparticle (NP) dimers was investigated using in situ transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). For the first time, the welding process was directly visualized. The structural and compositional evolution of Ag-Au dimers was studied in detail, and several typical nanostructures formed during the welding process, including two types of core-shell structures, were discovered. Based on these observations, we proposed a complete mechanism explaining how welding proceeds under the influence of a laser. Finite difference time domain (FDTD) simulations demonstrated that the plasmonic properties of welded Ag-Au dimers were different from those of pure Au-Au or Ag-Ag dimers and can be tuned by forming shells, alloying or changing the size ratio of Ag and Au NPs.
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Affiliation(s)
- Xiaohui Xu
- School of Materials Engineering, Purdue University, 701 West Stadium Avenue, West Lafayette, Indiana 47907, USA
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21
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VandenBussche EJ, Flannigan DJ. Sources of error in Debye-Waller-effect measurements relevant to studies of photoinduced structural dynamics. Ultramicroscopy 2018; 196:111-120. [PMID: 30352384 DOI: 10.1016/j.ultramic.2018.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 09/23/2018] [Accepted: 10/04/2018] [Indexed: 10/28/2022]
Abstract
We identify and quantify several practical effects likely to be present in both static and ultrafast electron-scattering experiments that may interfere with the Debye-Waller (DW) effect. Using 120-nm thick, small-grained, polycrystalline aluminum foils as a test system, we illustrate the impact of specimen tilting, in-plane translation, and changes in z height on Debye-Scherrer-ring intensities. We find that tilting by less than one degree can result in statistically-significant changes in diffracted-beam intensities for large specimen regions containing > 105 nanocrystalline grains. We demonstrate that, in addition to effective changes in the field of view with tilting, slight texturing of the film can result in deviations from expected DW-effect behavior. Further, we find that in-plane translations of as little as 20 nm also produce statistically-significant intensity changes, while normalization to total image counts eliminates such effects arising from changes in z height. The results indicate that the use of polycrystalline films in ultrafast electron-scattering experiments can greatly reduce the negative impacts of these effects as compared to single-crystal specimens, though it does not entirely eliminate them. Thus, it is important to account for such effects when studying thin-foil specimens having relatively short reciprocal-lattice rods.
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Affiliation(s)
- Elisah J VandenBussche
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN 55455, United States
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN 55455, United States.
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22
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Ultrafast Transmission Electron Microscopy: Historical Development, Instrumentation, and Applications. ADVANCES IN IMAGING AND ELECTRON PHYSICS 2018. [DOI: 10.1016/bs.aiep.2018.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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23
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Abela R, Beaud P, van Bokhoven JA, Chergui M, Feurer T, Haase J, Ingold G, Johnson SL, Knopp G, Lemke H, Milne CJ, Pedrini B, Radi P, Schertler G, Standfuss J, Staub U, Patthey L. Perspective: Opportunities for ultrafast science at SwissFEL. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:061602. [PMID: 29376109 PMCID: PMC5758366 DOI: 10.1063/1.4997222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 10/17/2017] [Indexed: 05/03/2023]
Abstract
We present the main specifications of the newly constructed Swiss Free Electron Laser, SwissFEL, and explore its potential impact on ultrafast science. In light of recent achievements at current X-ray free electron lasers, we discuss the potential territory for new scientific breakthroughs offered by SwissFEL in Chemistry, Biology, and Materials Science, as well as nonlinear X-ray science.
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Affiliation(s)
- Rafael Abela
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Paul Beaud
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Jeroen A van Bokhoven
- Laboratory for Catalysis and Sustainable Chemistry, Paul-Scherrer Institute, 5232 Villigen PSI, and Department of Chemistry, ETH-Zürich, 8093 Zürich, Switzerland
| | - Majed Chergui
- Laboratoire de Spectroscopie Ultrarapide (LSU) and Lausanne Centre for Ultrafast Science (LACUS), Ecole Polytechnique Fédérale de Lausanne (EPFL), ISIC-FSB, Station 6, 1015 Lausanne, Switzerland
| | - Thomas Feurer
- Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Johannes Haase
- Laboratory for Catalysis and Sustainable Chemistry, Paul-Scherrer Institute, 5232 Villigen PSI, and Department of Chemistry, ETH-Zürich, 8093 Zürich, Switzerland
| | - Gerhard Ingold
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Steven L Johnson
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zurich, Switzerland
| | - Gregor Knopp
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Henrik Lemke
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Chris J Milne
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Bill Pedrini
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Peter Radi
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | | | - Jörg Standfuss
- Division of Biology and Chemistry, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Urs Staub
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Luc Patthey
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
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24
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Zhang J, Zhao Z, Li J, Jin H, Rehman F, Chen P, Jiang Y, Chen C, Cao M, Zhao Y. Evolution of Structural and Electrical Properties of Oxygen-Deficient VO 2 under Low Temperature Heating Process. ACS APPLIED MATERIALS & INTERFACES 2017; 9:27135-27141. [PMID: 28753266 DOI: 10.1021/acsami.7b05792] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Structural stability and functional performances of vanadium dioxide (VO2) are strongly influenced by oxygen vacancies. However, the mechanism of metal-insulator transition (MIT) influenced by defects is still under debate. Here, we study the evolution of structure and electrical property of oxygen-deficient VO2 by a low temperature annealing process (LTP) based on a truss-structured VO2 nanonet. The oxygenation process of the oxygen-deficient VO2 is greatly prolonged, which enables us to probe the gradual change of properties of the oxygen-deficient VO2. A continuous lattice reduction is observed during LTP. No recrystallization and structural collapse of the VO2 nanonet can be found after LTP. The valence-band X-ray photoelectron spectroscopy (XPS) measurements indicate that the oxygen deficiency strongly affects the energy level of the valence band edge. Correspondingly, the resistance changes of the VO2 films from 1 to 4.5 orders of magnitude are achieved by LTP. The effect of oxygen vacancy on the electric field driven MIT is investigated. The threshold value of voltage triggering the MIT decreases with increasing the oxygen vacancy concentration. This work demonstrates a novel and effective way to control the content of oxygen vacancies in VO2 and the obvious impact of oxygen vacancy on MIT, facilitating further research on the role of oxygen vacancy in structure and MIT of VO2, which is important for the deep understanding of MIT and exploiting innovative functional application of VO2.
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Affiliation(s)
- Jiasong Zhang
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Zhengjing Zhao
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
| | - Jingbo Li
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
| | - Haibo Jin
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
| | - Fida Rehman
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
| | - Pengwan Chen
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
| | - Yijie Jiang
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Chunxu Chen
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Maosheng Cao
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
| | - Yongjie Zhao
- Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications, School of Materials Science and Engineering, Beijing Institute of Technology , Beijing 100081, China
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25
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Chergui M, Thomas JM. From structure to structural dynamics: Ahmed Zewail's legacy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:043802. [PMID: 28868324 PMCID: PMC5562505 DOI: 10.1063/1.4998243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 08/08/2017] [Indexed: 05/19/2023]
Abstract
In this brief tribute to Ahmed Zewail, we highlight and place in the historical context, several of the major achievements that he and his colleagues have made in Femtochemistry (of which he was the principal instigator) and his introduction of ultrafast electron scattering, diffraction, microscopy and spectroscopy. By achieving a sub-picosecond temporal resolution, coupled with a picometer spatial resolution, he revolutionised our understanding of the corpus of chemical, physical, biological and materials science systems.
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Affiliation(s)
- Majed Chergui
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide and Lausanne Centre for Ultrafast Science (LACUS), ISIC, Faculté des Sciences de Base, Station 6, CH-1015 Lausanne, Switzerland
| | - John Meurig Thomas
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB30FS, United Kingdom
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26
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Cremons DR, Plemmons DA, Flannigan DJ. Defect-mediated phonon dynamics in TaS 2 and WSe 2. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:044019. [PMID: 28503630 PMCID: PMC5411267 DOI: 10.1063/1.4982817] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 04/19/2017] [Indexed: 05/22/2023]
Abstract
We report correlative crystallographic and morphological studies of defect-dependent phonon dynamics in single flakes of 1T-TaS2 and 2H-WSe2 using selected-area diffraction and bright-field imaging in an ultrafast electron microscope. In both materials, we observe in-plane speed-of-sound acoustic-phonon wave trains, the dynamics of which (i.e., emergence, propagation, and interference) are strongly dependent upon discrete interfacial features (e.g., vacuum/crystal and crystal/crystal interfaces). In TaS2, we observe cross-propagating in-plane acoustic-phonon wave trains of differing frequencies that undergo coherent interference approximately 200 ps after initial emergence from distinct interfacial regions. With ultrafast bright-field imaging, the properties of the interfering wave trains are observed to correspond to the beat frequency of the individual oscillations, while intensity oscillations of Bragg spots generated from selected areas within the region of interest match well with the real-space dynamics. In WSe2, distinct acoustic-phonon dynamics are observed emanating and propagating away from structurally dissimilar morphological discontinuities (vacuum/crystal interface and crystal terrace), and results of ultrafast selected-area diffraction reveal thickness-dependent phonon frequencies. The overall observed dynamics are well-described using finite element analysis and time-dependent linear-elastic continuum mechanics.
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Affiliation(s)
- Daniel R Cremons
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | - Dayne A Plemmons
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
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27
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Ali H, Eriksson J, Li H, Jafri SHM, Kumar MS, Ögren J, Ziemann V, Leifer K. An electron energy loss spectrometer based streak camera for time resolved TEM measurements. Ultramicroscopy 2017; 176:5-10. [DOI: 10.1016/j.ultramic.2016.11.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/18/2016] [Accepted: 11/25/2016] [Indexed: 10/20/2022]
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28
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Adhikari A, Eliason JK, Sun J, Bose R, Flannigan DJ, Mohammed OF. Four-Dimensional Ultrafast Electron Microscopy: Insights into an Emerging Technique. ACS APPLIED MATERIALS & INTERFACES 2017; 9:3-16. [PMID: 27976852 DOI: 10.1021/acsami.6b12301] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Four-dimensional ultrafast electron microscopy (4D-UEM) is a novel analytical technique that aims to fulfill the long-held dream of researchers to investigate materials at extremely short spatial and temporal resolutions by integrating the excellent spatial resolution of electron microscopes with the temporal resolution of ultrafast femtosecond laser-based spectroscopy. The ingenious use of pulsed photoelectrons to probe surfaces and volumes of materials enables time-resolved snapshots of the dynamics to be captured in a way hitherto impossible by other conventional techniques. The flexibility of 4D-UEM lies in the fact that it can be used in both the scanning (S-UEM) and transmission (UEM) modes depending upon the type of electron microscope involved. While UEM can be employed to monitor elementary structural changes and phase transitions in samples using real-space mapping, diffraction, electron energy-loss spectroscopy, and tomography, S-UEM is well suited to map ultrafast dynamical events on materials surfaces in space and time. This review provides an overview of the unique features that distinguish these techniques and also illustrates the applications of both S-UEM and UEM to a multitude of problems relevant to materials science and chemistry.
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Affiliation(s)
- Aniruddha Adhikari
- King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Jeffrey K Eliason
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Jingya Sun
- King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Riya Bose
- King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Omar F Mohammed
- King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia
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29
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Bose R, Sun J, Khan JI, Shaheen BS, Adhikari A, Ng TK, Burlakov VM, Parida MR, Priante D, Goriely A, Ooi BS, Bakr OM, Mohammed OF. Real-Space Visualization of Energy Loss and Carrier Diffusion in a Semiconductor Nanowire Array Using 4D Electron Microscopy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:5106-5111. [PMID: 27111855 DOI: 10.1002/adma.201600202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/28/2016] [Indexed: 06/05/2023]
Abstract
A breakthrough in the development of 4D scanning ultrafast electron microscopy is described for real-time and space imaging of secondary electron energy loss and carrier diffusion on the surface of an array of nanowires as a model system, providing access to a territory that is beyond the reach of either static electron imaging or any time-resolved laser spectroscopy.
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Affiliation(s)
- Riya Bose
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Jingya Sun
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Jafar I Khan
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Basamat S Shaheen
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Aniruddha Adhikari
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Tien Khee Ng
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering, KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Victor M Burlakov
- Mathematical Institute, University of Oxford, Woodstock Road, Oxford, OX2 6GG, UK
| | - Manas R Parida
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Davide Priante
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering, KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Alain Goriely
- Mathematical Institute, University of Oxford, Woodstock Road, Oxford, OX2 6GG, UK
| | - Boon S Ooi
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering, KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Osman M Bakr
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Omar F Mohammed
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
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30
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Sun J, Adhikari A, Shaheen BS, Yang H, Mohammed OF. Mapping Carrier Dynamics on Material Surfaces in Space and Time using Scanning Ultrafast Electron Microscopy. J Phys Chem Lett 2016; 7:985-94. [PMID: 26911313 DOI: 10.1021/acs.jpclett.5b02908] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Selectively capturing the ultrafast dynamics of charge carriers on materials surfaces and at interfaces is crucial to the design of solar cells and optoelectronic devices. Despite extensive research efforts over the past few decades, information and understanding about surface-dynamical processes, including carrier trapping and recombination remains extremely limited. A key challenge is to selectively map such dynamic processes, a capability that is hitherto impractical by time-resolved laser techniques, which are limited by the laser's relatively large penetration depth and consequently these techniques record mainly bulk information. Such surface dynamics can only be mapped in real space and time by applying four-dimensional (4D) scanning ultrafast electron microscopy (S-UEM), which records snapshots of materials surfaces with nanometer spatial and subpicosecond temporal resolutions. In this method, the secondary electron (SE) signal emitted from the sample's surface is extremely sensitive to the surface dynamics and is detected in real time. In several unique applications, we spatially and temporally visualize the SE energy gain and loss, the charge carrier dynamics on the surface of InGaN nanowires and CdSe single crystal and its powder film. We also discuss the mechanisms for the observed dynamics, which will be the foundation for future potential applications of S-UEM to a wide range of studies on material surfaces and device interfaces.
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Affiliation(s)
- Jingya Sun
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Aniruddha Adhikari
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Basamat S Shaheen
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Haoze Yang
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Omar F Mohammed
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia
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Kieft E, Schliep KB, Suri PK, Flannigan DJ. Communication: Effects of thermionic-gun parameters on operating modes in ultrafast electron microscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:051101. [PMID: 26798820 PMCID: PMC4711641 DOI: 10.1063/1.4930174] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/25/2015] [Indexed: 05/06/2023]
Abstract
Ultrafast electron microscopes with thermionic guns and LaB6 sources can be operated in both the nanosecond, single-shot and femtosecond, single-electron modes. This has been demonstrated with conventional Wehnelt electrodes and absent any applied bias. Here, by conducting simulations using the General Particle Tracer code, we define the electron-gun parameter space within which various modes may be optimized. The properties of interest include electron collection efficiency, temporal and energy spreads, and effects of laser-pulse duration incident on the LaB6 source. We find that collection efficiencies can reach 100% for all modes, despite there being no bias applied to the electrode.
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Affiliation(s)
- Erik Kieft
- FEI Company , Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands
| | - Karl B Schliep
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
| | - Pranav K Suri
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
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32
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Inhomogeneity of the ultrafast insulator-to-metal transition dynamics of VO2. Nat Commun 2015; 6:6849. [DOI: 10.1038/ncomms7849] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 03/05/2015] [Indexed: 11/09/2022] Open
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33
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Carbone F. Dynamics deep from the core. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:020601. [PMID: 26798787 PMCID: PMC4711669 DOI: 10.1063/1.4918727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/06/2015] [Accepted: 04/10/2015] [Indexed: 06/05/2023]
Abstract
In van der Veen et al., [Struct. Dyn. 2, 024302 (2015)], femtosecond and nanosecond electron energy loss spectroscopy of deep core-levels are demonstrated. These results pave the way to the investigation of materials and molecules with combined energy, time, and spatial resolution in a transmission electron microscope. Furthermore, the authors elucidate the role of the electron phonon coupling in the band-gap renormalization that takes place in graphite upon photo-excitation.
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Affiliation(s)
- F Carbone
- Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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34
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Chen JL, Chang CC, Ho YK, Chen CL, Hsu CC, Jang WL, Wei DH, Dong CL, Pao CW, Lee JF, Chen JM, Guo J, Wu MK. Behind the color switching in gasochromic VO2. Phys Chem Chem Phys 2014; 17:3482-9. [PMID: 25533311 DOI: 10.1039/c4cp04623d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gasochromic VO2 thin films were fabricated by the sol-gel spin-coating technique. The results of X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy reveal that the origin of gasochromic coloration in VO2 is strongly related to the modulation of its structure and the electron-electron correlation. Upon gasochromic coloration, not only does the valence state change with the incorporation of hydrogen, but also the film undergoes the modification of the local atomic structure. The structural distortion varies the strength of hybridization of the O 2p-V 3d states and the bond distance of V-O and V-O varies. In the hydric process, the local atomic structure of VO2 changes from that of an un-symmetric to that of a symmetric V-O framework. The incorporated hydrogen adds electrons into the V 3d t2g orbital, enhancing the electron-electron correlation by reducing the V-V distance. This work presents a new physical insight in which the modulation of the electron-electron correlation is exploited to control the bleached and colored states, giving rise to the gasochromic phenomenon. The strong correlation among atomic spatial rearrangement, electronic structures, and transmittance supports a cooperative mechanism of the VO2 gasochromic transition. These results reveal a clear correlation between the dynamics of the lattice structure and the electronic properties and suggest a possible pathway to gasochromism and elucidation of its mechanism.
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Affiliation(s)
- Jeng-Lung Chen
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
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35
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Weissenrieder J, Gustafson J, Stacchiola D. Reactivity and Mass Transfer of Low-Dimensional Catalysts. CHEM REC 2014; 14:857-68. [DOI: 10.1002/tcr.201402006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Indexed: 11/12/2022]
Affiliation(s)
| | - Johan Gustafson
- Division of Synchrotron Radiation Research; Lund University; 221 00 Lund Sweden
| | - Dario Stacchiola
- Chemistry Department; Brookhaven National Laboratory; Upton NY 11973 USA
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36
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Magnetocaloric effects in a freestanding and flexible graphene-based superlattice synthesized with a spatially confined reaction. Nat Commun 2014; 5:3960. [DOI: 10.1038/ncomms4960] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 04/25/2014] [Indexed: 11/08/2022] Open
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37
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Xiao C, Li Z, Li K, Huang P, Xie Y. Decoupling interrelated parameters for designing high performance thermoelectric materials. Acc Chem Res 2014; 47:1287-95. [PMID: 24517646 DOI: 10.1021/ar400290f] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The world's supply of fossil fuels is quickly being exhausted, and the impact of their overuse is contributing to both climate change and global political unrest. In order to help solve these escalating problems, scientists must find a way to either replace combustion engines or reduce their use. Thermoelectric materials have attracted widespread research interest because of their potential applications as clean and renewable energy sources. They are reliable, lightweight, robust, and environmentally friendly and can reversibly convert between heat and electricity. However, after decades of development, the energy conversion efficiency of thermoelectric devices has been hovering around 10%. This is far below the theoretical predictions, mainly due to the interdependence and coupling between electrical and thermal parameters, which are strongly interrelated through the electronic structure of the materials. Therefore, any strategy that balances or decouples these parameters, in addition to optimizing the materials' intrinsic electronic structure, should be critical to the development of thermoelectric technology. In this Account, we discuss our recently developed strategies to decouple thermoelectric parameters for the synergistic optimization of electrical and thermal transport. We first highlight the phase transition, which is accompanied by an abrupt change of electrical transport, such as with a metal-insulator and semiconductor-superionic conductor transition. This should be a universal and effective strategy to optimize the thermoelectric performance, which takes advantage of modulated electronic structure and critical scattering across phase transitions to decouple the power factor and thermal conductivity. We propose that solid-solution homojunction nanoplates with disordered lattices are promising thermoelectric materials to meet the "phonon glass electron crystal" approach. The formation of a solid solution, coupled with homojunctions, allows for synergistically enhanced thermoelectric properties. This occurs through a significant reduction of thermal conductivity, without the deterioration of thermopower and electrical conductivity. In addition, we introduce the concept of spin entropy in wide band gap semiconductor nanocrystals, which acts to fully disentangle the otherwise interconnected quantities for synergistically optimized thermoelectric performance. Finally, we discuss a new concept we developed that is based on an ultrathin-nanosheet composite that we fabricated from ultrathin nanosheets of atomic thickness. These retain the original strong two-dimensional electron gas (2DEG) and allow for decoupled optimization of the three thermoelectric parameters, which improves thermoelectric performance.
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Affiliation(s)
- Chong Xiao
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Zhou Li
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Kun Li
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Pengcheng Huang
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Yi Xie
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
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38
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Baxter JB, Richter C, Schmuttenmaer CA. Ultrafast Carrier Dynamics in Nanostructures for Solar Fuels. Annu Rev Phys Chem 2014; 65:423-47. [DOI: 10.1146/annurev-physchem-040513-103742] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sunlight can be used to drive chemical reactions to produce fuels that store energy in chemical bonds. These fuels, such as hydrogen from splitting water, have much larger energy density than do electrical storage devices. The efficient conversion of clean, sustainable solar energy using photoelectrochemical and photocatalytic systems requires precise control over the thermodynamics, kinetics, and structural aspects of materials and molecules. Generation, thermalization, trapping, interfacial transfer, and recombination of photoexcited charge carriers often occur on femtosecond to picosecond timescales. These short timescales limit the transport of photoexcited carriers to nanometer-scale distances, but nanostructures with high surface-to-volume ratios can enable both significant light absorption and high quantum efficiency. This review highlights the importance of understanding ultrafast carrier dynamics for the generation of solar fuels, including case studies on colloidal nanostructures, nanostructured photoelectrodes, and photoelectrodes sensitized with molecular chromophores and catalysts.
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Affiliation(s)
- Jason B. Baxter
- Drexel University, Department of Chemical and Biological Engineering, Philadelphia, Pennsylvania 19104
| | - Christiaan Richter
- Rochester Institute of Technology, Department of Chemical Engineering, Rochester, New York 14623
| | - Charles A. Schmuttenmaer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516-7394
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39
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Liu H, Kwon OH, Tang J, Zewail AH. 4D imaging and diffraction dynamics of single-particle phase transition in heterogeneous ensembles. NANO LETTERS 2014; 14:946-54. [PMID: 24392689 DOI: 10.1021/nl404354g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this Letter, we introduce conical-scanning dark-field imaging in four-dimensional (4D) ultrafast electron microscopy to visualize single-particle dynamics of a polycrystalline ensemble undergoing phase transitions. Specifically, the ultrafast metal-insulator phase transition of vanadium dioxide is induced using laser excitation and followed by taking electron-pulsed, time-resolved images and diffraction patterns. The single-particle selectivity is achieved by identifying the origin of all constituent Bragg spots on Debye-Scherrer rings from the ensemble. Orientation mapping and dynamic scattering simulation of the electron diffraction patterns in the monoclinic and tetragonal phase during the transition confirm the observed behavior of Bragg spots change with time. We found that the threshold temperature for phase recovery increases with increasing particle sizes and we quantified the observation through a theoretical model developed for single-particle phase transitions. The reported methodology of conical scanning, orientation mapping in 4D imaging promises to be powerful for heterogeneous ensemble, as it enables imaging and diffraction at a given time with a full archive of structural information for each particle, for example, size, morphology, and orientation while minimizing radiation damage to the specimen.
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Affiliation(s)
- Haihua Liu
- Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology , Pasadena, California 91125, United States
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40
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Abstract
The opening of hard X-ray free-electron laser facilities, such as the Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory in the United States, has ushered in a new era in structural determination. With X-ray pulse durations down to 10 fs or shorter, and up to 10(13) transversely coherent photons per pulse in a narrow spectral bandwidth, focused irradiances of 10(18) to 10(21) W cm(-2) or higher can be produced at X-ray energies ranging from 500 eV to 10 keV. New techniques for determining the structure of systems that cannot be crystallized and for studying the time-resolved behavior of irreversible reactions at femtosecond timescales are now available.
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Affiliation(s)
- Anton Barty
- Center for Free-Electron Laser Science, DESY, 22607 Hamburg, Germany.
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41
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Aseyev SA, Weber PM, Ischenko AA. Ultrafast Electron Microscopy for Chemistry, Biology and Material Science. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/jasmi.2013.31005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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42
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Wu C, Feng F, Xie Y. Design of vanadium oxide structures with controllable electrical properties for energy applications. Chem Soc Rev 2013; 42:5157-83. [DOI: 10.1039/c3cs35508j] [Citation(s) in RCA: 347] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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43
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Ishchenko AA, Bagratashvili VN, Avilov AS. Methods for studying the coherent 4D structural dynamics of free molecules and condensed state of matter. CRYSTALLOGR REP+ 2011. [DOI: 10.1134/s1063774511050129] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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44
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Wu C, Feng F, Feng J, Dai J, Peng L, Zhao J, Yang J, Si C, Wu Z, Xie Y. Hydrogen-Incorporation Stabilization of Metallic VO2(R) Phase to Room Temperature, Displaying Promising Low-Temperature Thermoelectric Effect. J Am Chem Soc 2011; 133:13798-801. [DOI: 10.1021/ja203186f] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Changzheng Wu
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Feng Feng
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Jun Feng
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Jun Dai
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Lele Peng
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Jiyin Zhao
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Jinlong Yang
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Cheng Si
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Ziyu Wu
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
| | - Yi Xie
- Hefei National Laboratory for Physical Sciences at Microscale and ‡National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei, Anhui 230026, P.R. China
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45
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Liu JJ. Advanced Electron Microscopy of Metal-Support Interactions in Supported Metal Catalysts. ChemCatChem 2011. [DOI: 10.1002/cctc.201100090] [Citation(s) in RCA: 214] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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46
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Ortalan V, Zewail AH. 4D Scanning Transmission Ultrafast Electron Microscopy: Single-Particle Imaging and Spectroscopy. J Am Chem Soc 2011; 133:10732-5. [DOI: 10.1021/ja203821y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Volkan Ortalan
- Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Ahmed H. Zewail
- Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
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47
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Park ST, Flannigan DJ, Zewail AH. Irreversible chemical reactions visualized in space and time with 4D electron microscopy. J Am Chem Soc 2011; 133:1730-3. [PMID: 21254771 DOI: 10.1021/ja110952k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report direct visualization of irreversible chemical reactions in space and time with 4D electron microscopy. Specifically, transient structures are imaged following electron transfer in copper-tetracyanoquinodimethane [Cu(TCNQ)] crystals, and the oxidation/reduction process, which is irreversible, is elucidated using the single-shot operation mode of the microscope. We observed the fast, initial structural rearrangement due to Cu(+) reduction and the slower growth of metallic Cu(0) nanocrystals (Ostwald ripening) following initiation of the reaction with a pulse of visible light. The mechanism involves electron transfer from TCNQ anion-radical to Cu(+), morphological changes, and thermally driven growth of discrete Cu(0) nanocrystals embedded in an amorphous carbon skeleton of TCNQ. This in situ visualization of structures during reactions should be extendable to other classes of reactive systems.
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Affiliation(s)
- Sang Tae Park
- Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
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48
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Wu C, Zhang X, Dai J, Yang J, Wu Z, Wei S, Xie Y. Direct hydrothermal synthesis of monoclinic VO2(M) single-domain nanorods on large scale displaying magnetocaloric effect. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm03078c] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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49
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Tokita S, Hashida M, Inoue S, Nishoji T, Otani K, Sakabe S. Single-shot femtosecond electron diffraction with laser-accelerated electrons: experimental demonstration of electron pulse compression. PHYSICAL REVIEW LETTERS 2010; 105:215004. [PMID: 21231312 DOI: 10.1103/physrevlett.105.215004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Indexed: 05/30/2023]
Abstract
We report the first experimental demonstration of longitudinal compression of laser-accelerated electron pulses. Accelerated by a femtosecond laser pulse with an intensity of 10¹⁸ W/cm², an electron pulse with an energy of around 350 keV and a relative momentum spread of about 10⁻² was compressed to a 500-fs pulse at a distance of about 50 cm from the electron source by using a magnetic pulse compressor. This pulse was used to generate a clear diffraction pattern of a gold crystal in a single shot. This method solves the space-charge problem in ultrafast electron diffraction.
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Affiliation(s)
- Shigeki Tokita
- Advanced Research Center for Beam Science, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
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50
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Abstract
Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability.
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