1
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Hwang S, Wu L, Kisslinger K, Yang J, Egerton R, Zhu Y. Secondary-electron imaging of bulk crystalline specimens in an aberration corrected STEM. Ultramicroscopy 2024; 261:113967. [PMID: 38615523 DOI: 10.1016/j.ultramic.2024.113967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/03/2024] [Accepted: 04/09/2024] [Indexed: 04/16/2024]
Abstract
Atomic-scale electron microscopy traditionally probes thin specimens, with thickness below 100 nm, and its feasibility for bulk samples has not been documented. In this study, we explore the practicality of scanning transmission electron microscope (STEM) imaging with secondary electrons (SE), using a silicon-wedge specimen having a maximum thickness of 18 μm. We find that the atomic structure is present in the entire thickness range of the SE images although the background intensity increases moderately with thickness. The consistent intensity of secondary electron (SE) images at atomic positions and the modest increase in background intensity observed in silicon suggest a limited contribution from SEs generated by backscattered electrons, a conclusion supported by our multislice calculations. We conclude that achieving atomic resolution in SE imaging for bulk specimens is indeed attainable using aberration-corrected STEM and an aberration-corrected scanning electron microscope (SEM) may have the capacity for atomic-level resolution, holding great promise for future strides in materials research.
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Affiliation(s)
- Sooyeon Hwang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, New York 11973, United States
| | - Lijun Wu
- Condensed Matter Physics & Materials Science Department, Brookhaven National Laboratory, New York 11973, United States
| | - Kim Kisslinger
- Center for Functional Nanomaterials, Brookhaven National Laboratory, New York 11973, United States
| | - Judith Yang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, New York 11973, United States
| | - Ray Egerton
- Physics Department, University of Alberta, Edmonton T1W 2E2, Canada
| | - Yimei Zhu
- Condensed Matter Physics & Materials Science Department, Brookhaven National Laboratory, New York 11973, United States.
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2
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San Gabriel ML, Qiu C, Yu D, Yaguchi T, Howe JY. Simultaneous secondary electron microscopy in the scanning transmission electron microscope with applications for in situ studies. Microscopy (Oxf) 2024; 73:169-183. [PMID: 38334743 DOI: 10.1093/jmicro/dfae007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 12/09/2023] [Accepted: 02/05/2024] [Indexed: 02/10/2024] Open
Abstract
Scanning/transmission electron microscopy (STEM) is a powerful characterization tool for a wide range of materials. Over the years, STEMs have been extensively used for in situ studies of structural evolution and dynamic processes. A limited number of STEM instruments are equipped with a secondary electron (SE) detector in addition to the conventional transmitted electron detectors, i.e. the bright-field (BF) and annular dark-field (ADF) detectors. Such instruments are capable of simultaneous BF-STEM, ADF-STEM and SE-STEM imaging. These methods can reveal the 'bulk' information from BF and ADF signals and the surface information from SE signals for materials <200 nm thick. This review first summarizes the field of in situ STEM research, followed by the generation of SE signals, SE-STEM instrumentation and applications of SE-STEM analysis. Combining with various in situ heating, gas reaction and mechanical testing stages based on microelectromechanical systems (MEMS), we show that simultaneous SE-STEM imaging has found applications in studying the dynamics and transient phenomena of surface reconstructions, exsolution of catalysts, lunar and planetary materials and mechanical properties of 2D thin films. Finally, we provide an outlook on the potential advancements in SE-STEM from the perspective of sample-related factors, instrument-related factors and data acquisition and processing.
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Affiliation(s)
- Mia L San Gabriel
- Department of Materials Science and Engineering, University of Toronto, 184 College St, Toronto, ON M5S 3E4,Canada
| | - Chenyue Qiu
- Department of Materials Science and Engineering, University of Toronto, 184 College St, Toronto, ON M5S 3E4,Canada
| | - Dian Yu
- Department of Materials Science and Engineering, University of Toronto, 184 College St, Toronto, ON M5S 3E4,Canada
| | - Toshie Yaguchi
- Electron Microscope Systems Design Department, Hitachi High-Tech Corporation, 552-53 shinko-cho, Hitachinaka-shi, Ibaraki-ken 312-8504, Japan
| | - Jane Y Howe
- Department of Materials Science and Engineering, University of Toronto, 184 College St, Toronto, ON M5S 3E4,Canada
- Department of Chemical Engineering, University of Toronto, 200 College St, Toronto, ON M5T 3E5, Canada
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3
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Maciel-Escudero C, Yankovich AB, Munkhbat B, Baranov DG, Hillenbrand R, Olsson E, Aizpurua J, Shegai TO. Probing optical anapoles with fast electron beams. Nat Commun 2023; 14:8478. [PMID: 38123545 PMCID: PMC10733292 DOI: 10.1038/s41467-023-43813-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
Optical anapoles are intriguing charge-current distributions characterized by a strong suppression of electromagnetic radiation. They originate from the destructive interference of the radiation produced by electric and toroidal multipoles. Although anapoles in dielectric structures have been probed and mapped with a combination of near- and far-field optical techniques, their excitation using fast electron beams has not been explored so far. Here, we theoretically and experimentally analyze the excitation of optical anapoles in tungsten disulfide (WS2) nanodisks using Electron Energy Loss Spectroscopy (EELS) in Scanning Transmission Electron Microscopy (STEM). We observe prominent dips in the electron energy loss spectra and associate them with the excitation of optical anapoles and anapole-exciton hybrids. We are able to map the anapoles excited in the WS2 nanodisks with subnanometer resolution and find that their excitation can be controlled by placing the electron beam at different positions on the nanodisk. Considering current research on the anapole phenomenon, we envision EELS in STEM to become a useful tool for accessing optical anapoles appearing in a variety of dielectric nanoresonators.
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Affiliation(s)
- Carlos Maciel-Escudero
- Materials Physics Center, CSIC-UPV/EHU, Paseo de Manuel Lardizabal, Donostia-San Sebastián, 20018, Spain
- CIC NanoGUNE BRTA and Department of Electricity and Electronics, Tolosa Hiribidea, Donostia-San Sebastián, 20018, Spain
| | - Andrew B Yankovich
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden
| | - Battulga Munkhbat
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden
- Department of Photonics Engineering, Technical University of Denmark, Kgs. Lyngby, Copenhagen, 2800, Denmark
| | - Denis G Baranov
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
| | - Rainer Hillenbrand
- CIC NanoGUNE BRTA and Department of Electricity and Electronics, Tolosa Hiribidea, Donostia-San Sebastián, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48011, Spain
| | - Eva Olsson
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden.
| | - Javier Aizpurua
- Materials Physics Center, CSIC-UPV/EHU, Paseo de Manuel Lardizabal, Donostia-San Sebastián, 20018, Spain.
- Donostia International Physics Center, Paseo de Manuel Lardizabal, Donostia-San Sebastián, 20018, Spain.
| | - Timur O Shegai
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden.
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4
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Camino FE, Tiwale N, Hwang S, Du X, Yang JC. Mitigating challenges in aberration-corrected electron-beam lithography on electron-opaque substrates. NANOTECHNOLOGY 2023; 35:065301. [PMID: 37918028 DOI: 10.1088/1361-6528/ad0908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/02/2023] [Indexed: 11/04/2023]
Abstract
Aberration-corrected electron-beam lithography (AC-EBL) using ultra-thin electron transparent membranes has achieved single-digit nanometer resolution in two widely used electron-beam resists: poly (methyl methacrylate) (PMMA) and hydrogen silsesquioxane. On the other hand, AC-EBL implementation on thick, electron-opaque substrates is appealing for conventional top-down fabrication of quantum devices with nanometer-scale features. To investigate the performance of AC-EBL on thick substrates, we measured the lithographic point spread function of a 200 keV aberration-corrected scanning transmission electron microscope by defining both positive and negative patterns in PMMA thin films, spin-cast on thick SiO2/Si substrates. We present the problems encountered during pre-exposure beam focusing and discuss methods to overcome them. In addition, applying some of these methods using commercial 50 nm thick SiNXmembranes with thick Si support frames, we printed arrays of holes in PMMA with pitches around 26 nm on SiNX/Si substrates with increasing Si thickness. Our results show that proximity effects from even 50 nm thick SiNXmembranes limit hole arrays to 20 nm pitch; however, down to this limit, the effect of the substrate thickness on the pattern quality is minimal. These results highlight the need for novel resists less susceptible to proximity effects, or resists which can be used directly, after development, as the dielectric material in periodic gates in 2D quantum devices.
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Affiliation(s)
- Fernando E Camino
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, United States of America
| | - Nikhil Tiwale
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, United States of America
| | - Sooyeon Hwang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, United States of America
| | - Xu Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook NY 11794, United States of America
| | - Judith C Yang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, United States of America
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5
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Hotz MT, Martis J, Radlicka T, Bacon NJ, Dellby N, Lovejoy TC, Quillin SC, Hwang HY, Singh P, Krivanek OL. Atomic Resolution SE Imaging in a 30-200 keV Aberration-corrected UHV STEM. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:2064-2065. [PMID: 37612905 DOI: 10.1093/micmic/ozad067.1068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- M T Hotz
- Nion R&D, 11511 NE 118th St, Kirkland, WA, USA
| | - J Martis
- Nion R&D, 11511 NE 118th St, Kirkland, WA, USA
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - T Radlicka
- Institute of Scientific Instruments of CAS, Královopolská 147, Brno, Czech Republic
| | - N J Bacon
- Nion R&D, 11511 NE 118th St, Kirkland, WA, USA
| | - N Dellby
- Nion R&D, 11511 NE 118th St, Kirkland, WA, USA
| | - T C Lovejoy
- Nion R&D, 11511 NE 118th St, Kirkland, WA, USA
| | - S C Quillin
- Nion R&D, 11511 NE 118th St, Kirkland, WA, USA
| | - H Y Hwang
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - P Singh
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - O L Krivanek
- Nion R&D, 11511 NE 118th St, Kirkland, WA, USA
- Department of Physics, Arizona State University, Tempe, AZ, USA
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6
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Hwang S. Secondary Electron Imaging on Aberration-Corrected STEM for Characterizing Catalyst Materials. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:764-765. [PMID: 37613355 DOI: 10.1093/micmic/ozad067.377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Sooyeon Hwang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, United States
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7
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Egerton R, Hwang S, Zhu Y. Atomic-scale Secondary-electron Imaging in the STEM and SEM. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:452-453. [PMID: 37613030 DOI: 10.1093/micmic/ozad067.212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Ray Egerton
- Physics Department, University of Alberta, Edmonton, Canada
| | - Sooyeon Hwang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, United States
| | - Yimei Zhu
- Electron Microscopy and Nanostructure Group, Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, United States
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8
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Pu Y, He B, Niu Y, Liu X, Zhang B. Chemical Electron Microscopy (CEM) for Heterogeneous Catalysis at Nano: Recent Progress and Challenges. RESEARCH (WASHINGTON, D.C.) 2023; 6:0043. [PMID: 36930759 PMCID: PMC10013794 DOI: 10.34133/research.0043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 12/18/2022] [Indexed: 01/12/2023]
Abstract
Chemical electron microscopy (CEM), a toolbox that comprises imaging and spectroscopy techniques, provides dynamic morphological, structural, chemical, and electronic information about an object in chemical environment under conditions of observable performance. CEM has experienced a revolutionary improvement in the past years and is becoming an effective characterization method for revealing the mechanism of chemical reactions, such as catalysis. Here, we mainly address the concept of CEM for heterogeneous catalysis in the gas phase and what CEM could uniquely contribute to catalysis, and illustrate what we can know better with CEM and the challenges and future development of CEM.
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Affiliation(s)
- Yinghui Pu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.,School of Materials Science and Engineering, University of Science and Technology of China, 72 Wenhua Road, Shenyang 110016, China
| | - Bowen He
- School of Chemistry and Chemical Engineering, In-situ Center for Physical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yiming Niu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.,School of Materials Science and Engineering, University of Science and Technology of China, 72 Wenhua Road, Shenyang 110016, China
| | - Xi Liu
- School of Chemistry and Chemical Engineering, In-situ Center for Physical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bingsen Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.,School of Materials Science and Engineering, University of Science and Technology of China, 72 Wenhua Road, Shenyang 110016, China
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9
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Susi T. Identifying and manipulating single atoms with scanning transmission electron microscopy. Chem Commun (Camb) 2022; 58:12274-12285. [PMID: 36260089 PMCID: PMC9632407 DOI: 10.1039/d2cc04807h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/28/2022] [Indexed: 08/25/2023]
Abstract
The manipulation of individual atoms has developed from visionary speculation into an established experimental science. Using focused electron irradiation in a scanning transmission electron microscope instead of a physical tip in a scanning probe microscope confers several benefits, including thermal stability of the manipulated structures, the ability to reach into bulk crystals, and the chemical identification of single atoms. However, energetic electron irradiation also presents unique challenges, with an inevitable possibility of irradiation damage. Understanding the underlying mechanisms will undoubtedly continue to play an important role to guide experiments. Great progress has been made in several materials including graphene, carbon nanotubes, and crystalline silicon in the eight years since the discovery of electron-beam manipulation, but the important challenges that remain will determine how far we can expect to progress in the near future.
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Affiliation(s)
- Toma Susi
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
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10
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Egerton R, Watanabe M. Spatial Resolution in Transmission Electron Microscopy. Micron 2022; 160:103304. [DOI: 10.1016/j.micron.2022.103304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/05/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
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11
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Dyck O, Swett JL, Evangeli C, Lupini AR, Mol J, Jesse S. Contrast Mechanisms in Secondary Electron e-Beam-Induced Current (SEEBIC) Imaging. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-17. [PMID: 35644675 DOI: 10.1017/s1431927622000824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Over the last few years, a new mode for imaging in the scanning transmission electron microscope (STEM) has gained attention as it permits the direct visualization of sample conductivity and electrical connectivity. When the electron beam (e-beam) is focused on the sample in the STEM, secondary electrons (SEs) are generated. If the sample is conductive and electrically connected to an amplifier, the SE current can be measured as a function of the e-beam position. This scenario is similar to the better-known scanning electron microscopy-based technique, electron beam-induced current imaging, except that the signal in the STEM is generated by the emission of SEs, hence the name secondary electron e-beam-induced current (SEEBIC), and in this case, the current flows in the opposite direction. Here, we provide a brief review of recent work in this area, examine the various contrast generation mechanisms associated with SEEBIC, and illustrate its use for the characterization of graphene nanoribbon devices.
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Affiliation(s)
- Ondrej Dyck
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Jacob L Swett
- Biodesign Institute, Arizona State University, Tempe, AZ 87287, USA
- Department of Materials, University of Oxford, Oxford OX1 3PH, UK
| | | | - Andrew R Lupini
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Jan Mol
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, UK
| | - Stephen Jesse
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
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12
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Ishikawa R, Ueno Y, Ikuhara Y, Shibata N. Direct Observation of Atomistic Reaction Process between Pt Nanoparticles and TiO 2 (110). NANO LETTERS 2022; 22:4161-4167. [PMID: 35533402 DOI: 10.1021/acs.nanolett.2c00929] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The catalytic activity and selectivity of heterogeneous catalysts are governed by atomic and electronic structures at the heterointerface between noble metal nanoparticles (NPs) and oxide substrates. In specific chemical reactions, it is well-known that the catalytic activity is strongly suppressed by annealing in a reducing atmosphere, so-called strong metal-support interaction (SMSI). However, it is still unclear the formation process and atomistic origin of the SMSI. By preparing well-defined platinum (Pt) NPs supported on atomically flat TiO2 (110) substrate, we directly show the formation of chemically ordered Pt-Ti intermetallic NPs and impregnation of NPs into TiO2 substrate at high temperatures by using atomic-resolution scanning transmission electron microscopy combined with electron energy-loss spectroscopy. Furthermore, we observed negative charge transfer from the Pt-Ti intermetallic NPs to the TiO2 surface, which would strongly affect the catalytic activities.
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Affiliation(s)
- Ryo Ishikawa
- Institute of Engineering Innovation, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Yujiro Ueno
- Institute of Engineering Innovation, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
| | - Yuichi Ikuhara
- Institute of Engineering Innovation, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, Aichi 456-8587, Japan
| | - Naoya Shibata
- Institute of Engineering Innovation, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, Aichi 456-8587, Japan
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13
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Watts S, Kaur I, Singh S, Jimenez B, Chavana J, Kariyat R. Desktop scanning electron microscopy in plant-insect interactions research: a fast and effective way to capture electron micrographs with minimal sample preparation. Biol Methods Protoc 2022; 7:bpab020. [PMID: 35036571 PMCID: PMC8754489 DOI: 10.1093/biomethods/bpab020] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/09/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
The ability to visualize cell and tissue morphology at a high magnification using scanning electron microscopy (SEM) has revolutionized plant sciences research. In plant-insect interactions studies, SEM-based imaging has been of immense assistance to understand plant surface morphology including trichomes [plant hairs; physical defense structures against herbivores], spines, waxes, and insect morphological characteristics such as mouth parts, antennae, and legs, that they interact with. While SEM provides finer details of samples, and the imaging process is simpler now with advanced image acquisition and processing, sample preparation methodology has lagged. The need to undergo elaborate sample preparation with cryogenic freezing, multiple alcohol washes, and sputter coating makes SEM imaging expensive, time consuming, and warrants skilled professionals, making it inaccessible to majority of scientists. Here, using a desktop version of SEM (SNE- 4500 Plus Tabletop), we show that the "plug and play" method can efficiently produce SEM images with sufficient details for most morphological studies in plant-insect interactions. We used leaf trichomes of Solanum genus as our primary model, and oviposition by tobacco hornworm (Manduca sexta; Lepidoptera: Sphingidae) and fall armyworm (Spodoptera frugiperda; Lepidoptera: Noctuidae), and leaf surface wax imaging as additional examples to show the effectiveness of this instrument and present a detailed methodology to produce the best results with this instrument. While traditional sample preparation can still produce better resolved images with less distortion, we show that even at a higher magnification, the desktop SEM can deliver quality images. Overall, this study provides detailed methodology with a simpler "no sample preparation" technique for scanning fresh biological samples without the use of any additional chemicals and machinery.
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Affiliation(s)
- Sakshi Watts
- Department of Biology, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA
| | - Ishveen Kaur
- School of Earth, Environment and Marine Sciences, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA
| | - Sukhman Singh
- Department of Biology, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA
| | - Bianca Jimenez
- Department of Biology, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA
| | - Jesus Chavana
- Department of Biology, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA
| | - Rupesh Kariyat
- Department of Biology, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA.,School of Earth, Environment and Marine Sciences, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA
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14
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Egerton RF, Zhu Y. OUP accepted manuscript. Microscopy (Oxf) 2022; 72:66-77. [PMID: 35535685 DOI: 10.1093/jmicro/dfac022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/09/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
We first review the significance of resolution and contrast in electron microscopy and the effect of the electron optics on these two quantities. We then outline the physics of the generation of secondary electrons (SEs) and their transport and emission from the surface of a specimen. Contrast and resolution are discussed for different kinds of SE imaging in scanning electron microscope (SEM) and scanning-transmission microscope instruments, with some emphasis on the observation of individual atoms and atomic columns in a thin specimen. The possibility of achieving atomic resolution from a bulk specimen at SEM energies is also considered.
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Affiliation(s)
- R F Egerton
- Physics Department, University of Alberta, Edmonton, Alberta T1W 2E2, Canada
| | - Y Zhu
- Electron Microscopy and Nanostructure Group, Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY 11973, USA
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15
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Zhao H, Zhang C, Li H, Fang J. One‐dimensional nanomaterial supported metal single‐atom electrocatalysts: Synthesis, characterization, and applications. NANO SELECT 2021. [DOI: 10.1002/nano.202100083] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Haoyue Zhao
- National Engineering Laboratory for Modern Silk College of Textile and Clothing Engineering Soochow University Suzhou China
| | - Chuanxiong Zhang
- Textile Industry Science and Technology Development Center Beijing China
| | - Han Li
- Institute for Frontier Materials Deakin University Geelong Victoria Australia
| | - Jian Fang
- National Engineering Laboratory for Modern Silk College of Textile and Clothing Engineering Soochow University Suzhou China
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16
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Dyck O, Swett JL, Lupini AR, Mol JA, Jesse S. Imaging Secondary Electron Emission from a Single Atomic Layer. SMALL METHODS 2021; 5:e2000950. [PMID: 34927845 DOI: 10.1002/smtd.202000950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/17/2020] [Indexed: 06/14/2023]
Abstract
Graphene-based devices hold promise for a wide range of technological applications. Yet characterizing the structure and the electrical properties of a material that is only one atomic layer thick still poses technical challenges. Recent investigations indicate that secondary-electron electron-beam-induced current (SE-EBIC) imaging can reveal subtle details regarding electrical conductivity and electron transport with high spatial resolution. Here, it is shown that the SEEBIC imaging mode can be used to detect suspended single layers of graphene and distinguish between different numbers of layers. Pristine and contaminated areas of graphene are also compared to show that pristine graphene exhibits a substantially lower SE yield than contaminated regions. This SEEBIC imaging mode may provide valuable information for the engineering of surface coatings where SE yield is a priority.
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Affiliation(s)
- Ondrej Dyck
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Jacob L Swett
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
| | - Andrew R Lupini
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Jan A Mol
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
- School of Physics and Astronomy, Queen Mary University of London, London, E1 4NS, UK
| | - Stephen Jesse
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
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17
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Tang M, Yuan W, Ou Y, Li G, You R, Li S, Yang H, Zhang Z, Wang Y. Recent Progresses on Structural Reconstruction of Nanosized Metal Catalysts via Controlled-Atmosphere Transmission Electron Microscopy: A Review. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03335] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Min Tang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Wentao Yuan
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yang Ou
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Guanxing Li
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ruiyang You
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Songda Li
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hangsheng Yang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ze Zhang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yong Wang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
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18
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SATO T, AIZAWA Y, MATSUMOTO H, KIYOHARA M, KAMIYA C, VON CUBE F. Low damage lamella preparation of metallic materials by FIB processing with low acceleration voltage and a low incident angle Ar ion milling finish. J Microsc 2020; 279:234-241. [DOI: 10.1111/jmi.12878] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 01/24/2020] [Accepted: 02/06/2020] [Indexed: 11/28/2022]
Affiliation(s)
- T. SATO
- Hitachi High‐Technologies CorporationIchige Hitachinaka‐shi Ibaraki Japan
| | - Y. AIZAWA
- Hitachi High‐Technologies CorporationIchige Hitachinaka‐shi Ibaraki Japan
| | - H. MATSUMOTO
- Hitachi High‐Technologies CorporationIchige Hitachinaka‐shi Ibaraki Japan
| | - M. KIYOHARA
- Hitachi High‐Tech Science CorporationTakenoshita Oyama‐cho Shizuoka Japan
| | - C. KAMIYA
- Hitachi High‐Technologies CorporationIchige Hitachinaka‐shi Ibaraki Japan
| | - F. VON CUBE
- Hitachi High‐Technologies Europe GmbHEuropark, Fichtenhain Krefeld Germany
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19
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Electron beam-induced current imaging with two-angstrom resolution. Ultramicroscopy 2019; 207:112852. [PMID: 31678644 DOI: 10.1016/j.ultramic.2019.112852] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/26/2019] [Accepted: 09/29/2019] [Indexed: 11/22/2022]
Abstract
An electron microscope's primary beam simultaneously ejects secondary electrons (SEs) from the sample and generates electron beam-induced currents (EBICs) in the sample. Both signals can be captured and digitized to produce images. The off-sample Everhart-Thornley detectors that are common in scanning electron microscopes (SEMs) can detect SEs with low noise and high bandwidth. However, the transimpedance amplifiers appropriate for detecting EBICs do not have such good performance, which makes accessing the benefits of EBIC imaging at high-resolution relatively more challenging. Here we report lattice-resolution imaging via detection of the EBIC produced by SE emission (SEEBIC). We use an aberration-corrected scanning transmission electron microscope (STEM), and image both microfabricated devices and standard calibration grids.
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20
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Lu Y, Kuo CT, Kovarik L, Hoffman AS, Boubnov A, Driscoll DM, Morris JR, Bare SR, Karim AM. A versatile approach for quantification of surface site fractions using reaction kinetics: The case of CO oxidation on supported Ir single atoms and nanoparticles. J Catal 2019. [DOI: 10.1016/j.jcat.2019.08.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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21
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22
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Sun C, Müller E, Meffert M, Gerthsen D. On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2018; 24:99-106. [PMID: 29589573 DOI: 10.1017/s1431927618000181] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Transmission electron microscopy (TEM) with low-energy electrons has been recognized as an important addition to the family of electron microscopies as it may avoid knock-on damage and increase the contrast of weakly scattering objects. Scanning electron microscopes (SEMs) are well suited for low-energy electron microscopy with maximum electron energies of 30 keV, but they are mainly used for topography imaging of bulk samples. Implementation of a scanning transmission electron microscopy (STEM) detector and a charge-coupled-device camera for the acquisition of on-axis transmission electron diffraction (TED) patterns, in combination with recent resolution improvements, make SEMs highly interesting for structure analysis of some electron-transparent specimens which are traditionally investigated by TEM. A new aspect is correlative SEM, STEM, and TED imaging from the same specimen region in a SEM which leads to a wealth of information. Simultaneous image acquisition gives information on surface topography, inner structure including crystal defects and qualitative material contrast. Lattice-fringe resolution is obtained in bright-field STEM imaging. The benefits of correlative SEM/STEM/TED imaging in a SEM are exemplified by structure analyses from representative sample classes such as nanoparticulates and bulk materials.
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Affiliation(s)
- Cheng Sun
- Laboratorium für Elektronenmikroskopie,Karlsruher Institut für Technologie (KIT),Engesserstr. 7,76131 Karlsruhe,Germany
| | - Erich Müller
- Laboratorium für Elektronenmikroskopie,Karlsruher Institut für Technologie (KIT),Engesserstr. 7,76131 Karlsruhe,Germany
| | - Matthias Meffert
- Laboratorium für Elektronenmikroskopie,Karlsruher Institut für Technologie (KIT),Engesserstr. 7,76131 Karlsruhe,Germany
| | - Dagmar Gerthsen
- Laboratorium für Elektronenmikroskopie,Karlsruher Institut für Technologie (KIT),Engesserstr. 7,76131 Karlsruhe,Germany
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23
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Chee AKW. Enhancing doping contrast and optimising quantification in the scanning electron microscope by surface treatment and Fermi level pinning. Sci Rep 2018; 8:5247. [PMID: 29588446 PMCID: PMC5869679 DOI: 10.1038/s41598-018-22909-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/26/2018] [Indexed: 11/09/2022] Open
Abstract
Recent advances in two-dimensional dopant profiling in the scanning electron microscope have enabled a high throughput, non-contact process diagnostics and failure analysis solution for integrated device manufacturing. The routine (electro)chemical etch processes to obtain contamination-free, hydrogen-terminated silicon surfaces is industrially important in ULSI microfabrication, though doping contrast, which is the basis for quantitative dopant profiling, will be strongly altered. We show herein that ammonium-fluoride treatment not only enabled doping contrast to be differentiated mainly by surface band-bending, but it enhanced the quality of linear quantitative calibration through simple univariate analysis for SE energies as low as 1 eV. Energy-filtering measurements reveal that the linear analytical model broached in the literature (c.f. Kazemian et al., 2006 and Kazemian et al., 2007) is likely to be inadequate to determine the surface potential across semiconductor p-n junctions without suitable deconvolution methods. Nevertheless, quantification trends suggest that energy-filtering may not be crucial if patch fields and contamination are absolutely suppressed by the appropriate edge termination and passivation.
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Affiliation(s)
- Augustus K W Chee
- Centre for Advanced Photonics and Electronics, Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, United Kingdom. .,Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom.
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24
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Sato T, Orai Y, Suzuki Y, Ito H, Isshiki T, Fukui M, Nakamura K, Schamp CT. Surface morphology and dislocation characteristics near the surface of 4H-SiC wafer using multi-directional scanning transmission electron microscopy. Microscopy (Oxf) 2017; 66:337-347. [PMID: 29016923 DOI: 10.1093/jmicro/dfx022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/31/2017] [Indexed: 06/07/2023] Open
Abstract
To improve the reliability of silicon carbide (SiC) electronic power devices, the characteristics of various kinds of crystal defects should be precisely understood. Of particular importance is understanding the correlation between the surface morphology and the near surface dislocations. In order to analyze the dislocations near the surface of 4H-SiC wafers, a dislocation analysis protocol has been developed. This protocol consists of the following process: (1) inspection of surface defects using low energy scanning electron microscopy (LESEM), (2) identification of small and shallow etch pits using KOH low temperature etching, (3) classification of etch pits using LESEM, (4) specimen preparation of several hundred nanometer thick sample using the in-situ focused ion beam micro-sampling® technique, (5) crystallographic analysis using the selected diffraction mode of the scanning transmission electron microscope (STEM), and (6) determination of the Burgers vector using multi-directional STEM (MD-STEM). The results show a correlation between the triangular terrace shaped surface defects and an hexagonal etch pit arising from threading dislocations, linear shaped surface defects and elliptical shaped etch pits arising from basal plane dislocations. Through the observation of the sample from two orthogonal directions via the MD-STEM technique, a basal plane dislocation is found to dissociate into an extended dislocation bound by two partial dislocations. A protocol developed and presented in this paper enables one to correlate near surface defects of a 4H-SiC wafer with the root cause dislocations giving rise to those surface defects.
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Affiliation(s)
- Takahiro Sato
- Hitachi High-Technologies Corp. 1040, Ichige, Hitachinaka-shi, Ibaraki, Japan
- Kyoto Institute of Technology, 1, Matsugasaki-hashikamicyo, Sakyo-ku, Kyoto, Japan
| | - Yoshihisa Orai
- Hitachi High-Technologies Corp. 1040, Ichige, Hitachinaka-shi, Ibaraki, Japan
| | - Yuya Suzuki
- Hitachi High-Technologies Corp. 1040, Ichige, Hitachinaka-shi, Ibaraki, Japan
| | - Hiroyuki Ito
- Hitachi High-Technologies Corp. 1040, Ichige, Hitachinaka-shi, Ibaraki, Japan
| | - Toshiyuki Isshiki
- Kyoto Institute of Technology, 1, Matsugasaki-hashikamicyo, Sakyo-ku, Kyoto, Japan
| | - Munetoshi Fukui
- Hitachi High-Technologies Corp. 1040, Ichige, Hitachinaka-shi, Ibaraki, Japan
| | - Kuniyasu Nakamura
- Hitachi High-Technologies Corp. 1040, Ichige, Hitachinaka-shi, Ibaraki, Japan
| | - C T Schamp
- Hitachi High-Technologies Corp. in America, 22610 Gateway Center Dr., Suite 100, Clarksburg, MD, USA
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25
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Kubo Y, Yonezawa K. Nanoscale Phase-Separated Structure in Core-Shell Nanoparticles of SiO 2-Si 1-xGe xO 2 Glass Revealed by Electron Microscopy. Anal Chem 2017; 89:8772-8781. [PMID: 28759194 DOI: 10.1021/acs.analchem.7b00976] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
SiO2-based optical fibers are indispensable components of modern information communication technologies. It has recently become increasingly important to establish a technique for visualizing the nanoscale phase-separated structure inside SiO2-GeO2 glass nanoparticles during the manufacturing of SiO2-GeO2 fibers. This is because the rapidly increasing price of Ge has made it necessary to improve the Ge yield by clarifying the detailed mechanism of Ge diffusion into SiO2. However, direct observation of the internal nanostructure of glass particles has been extremely difficult, mainly due to electrostatic charging and the damage induced by electron and X-ray irradiation. In the present study, we used state-of-the-art scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDX) to examine cross-sectional samples of SiO2-GeO2 particles embedded in an epoxy resin, which were fabricated using a broad Ar ion beam and a focused Ga ion beam. These advanced techniques enabled us to observe the internal phase-separated structure of the nanoparticles. We have for the first time clearly determined the SiO2-Si1-xGexO2 core-shell structure of such particles, the element distribution, the degree of crystallinity, and the quantitative chemical composition of microscopic regions, and we discuss the formation mechanism for the observed structure. The proposed imaging protocol is highly promising for studying the internal structure of various core-shell nanoparticles, which affects their catalytic, optical, and electronic properties.
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Affiliation(s)
- Yugo Kubo
- Sumitomo Electric Industries, Limited , 1-1-3 Shimaya, Konohana-ku Osaka-shi, Osaka 554-0024, Japan
| | - Kazuhiro Yonezawa
- Sumitomo Electric Industries, Limited , 1-1-3 Shimaya, Konohana-ku Osaka-shi, Osaka 554-0024, Japan
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26
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Manfrinato VR, Stein A, Zhang L, Nam CY, Yager KG, Stach EA, Black CT. Aberration-Corrected Electron Beam Lithography at the One Nanometer Length Scale. NANO LETTERS 2017; 17:4562-4567. [PMID: 28418673 DOI: 10.1021/acs.nanolett.7b00514] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Patterning materials efficiently at the smallest length scales is a longstanding challenge in nanotechnology. Electron-beam lithography (EBL) is the primary method for patterning arbitrary features, but EBL has not reliably provided sub-4 nm patterns. The few competing techniques that have achieved this resolution are orders of magnitude slower than EBL. In this work, we employed an aberration-corrected scanning transmission electron microscope for lithography to achieve unprecedented resolution. Here we show aberration-corrected EBL at the one nanometer length scale using poly(methyl methacrylate) (PMMA) and have produced both the smallest isolated feature in any conventional resist (1.7 ± 0.5 nm) and the highest density patterns in PMMA (10.7 nm pitch for negative-tone and 17.5 nm pitch for positive-tone PMMA). We also demonstrate pattern transfer from the resist to semiconductor and metallic materials at the sub-5 nm scale. These results indicate that polymer-based nanofabrication can achieve feature sizes comparable to the Kuhn length of PMMA and ten times smaller than its radius of gyration. Use of aberration-corrected EBL will increase the resolution, speed, and complexity in nanomaterial fabrication.
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Affiliation(s)
- Vitor R Manfrinato
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973-5000, United States
| | - Aaron Stein
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973-5000, United States
| | - Lihua Zhang
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973-5000, United States
| | - Chang-Yong Nam
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973-5000, United States
| | - Kevin G Yager
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973-5000, United States
| | - Eric A Stach
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973-5000, United States
| | - Charles T Black
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973-5000, United States
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27
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Han MG, Garlow JA, Marshall MSJ, Tiano AL, Wong SS, Cheong SW, Walker FJ, Ahn CH, Zhu Y. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes. Ultramicroscopy 2017; 176:80-85. [PMID: 28359670 DOI: 10.1016/j.ultramic.2017.03.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 01/03/2017] [Accepted: 01/22/2017] [Indexed: 11/19/2022]
Abstract
The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.
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Affiliation(s)
- Myung-Geun Han
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Joseph A Garlow
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA; Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794, USA
| | | | - Amanda L Tiano
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11974, USA
| | - Stanislaus S Wong
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA; Department of Chemistry, Stony Brook University, Stony Brook, NY 11974, USA
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854, USA
| | - Frederick J Walker
- Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA
| | - Charles H Ahn
- Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA
| | - Yimei Zhu
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA
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28
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Han MG, Garlow JA, Marshall MSJ, Tiano AL, Wong SS, Cheong SW, Walker FJ, Ahn CH, Zhu Y. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes. Ultramicroscopy 2017; 177:14-19. [PMID: 28193560 DOI: 10.1016/j.ultramic.2017.01.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 01/03/2017] [Accepted: 01/22/2017] [Indexed: 11/25/2022]
Abstract
The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.
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Affiliation(s)
- Myung-Geun Han
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Joseph A Garlow
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA; Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794, USA
| | | | - Amanda L Tiano
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11974, USA
| | - Stanislaus S Wong
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA; Department of Chemistry, Stony Brook University, Stony Brook, NY 11974, USA
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854, USA
| | - Frederick J Walker
- Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA
| | - Charles H Ahn
- Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA
| | - Yimei Zhu
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA
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29
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Walker CGH, Frank L, Müllerová I. Simulations and measurements in scanning electron microscopes at low electron energy. SCANNING 2016; 38:802-818. [PMID: 27285145 DOI: 10.1002/sca.21330] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/16/2016] [Indexed: 06/06/2023]
Abstract
The advent of new imaging technologies in Scanning Electron Microscopy (SEM) using low energy (0-2 keV) electrons has brought about new ways to study materials at the nanoscale. It also brings new challenges in terms of understanding electron transport at these energies. In addition, reduction in energy has brought new contrast mechanisms producing images that are sometimes difficult to interpret. This is increasing the push for simulation tools, in particular for low impact energies of electrons. The use of Monte Carlo calculations to simulate the transport of electrons in materials has been undertaken by many authors for several decades. However, inaccuracies associated with the Monte Carlo technique start to grow as the energy is reduced. This is not simply associated with inaccuracies in the knowledge of the scattering cross-sections, but is fundamental to the Monte Carlo technique itself. This is because effects due to the wave nature of the electron and the energy band structure of the target above the vacuum energy level become important and these are properties which are difficult to handle using the Monte Carlo method. In this review we briefly describe the new techniques of scanning low energy electron microscopy and then outline the problems and challenges of trying to understand and quantify the signals that are obtained. The effects of charging and spin polarised measurement are also briefly explored. SCANNING 38:802-818, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Luděk Frank
- Institute of Scientific Instruments, Brno, Czech Republic
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30
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Pilger F, Testino A, Carino A, Proff C, Kambolis A, Cervellino A, Ludwig C. Size Control of Pt Clusters on CeO2 Nanoparticles via an Incorporation–Segregation Mechanism and Study of Segregation Kinetics. ACS Catal 2016. [DOI: 10.1021/acscatal.6b00934] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Frank Pilger
- Paul Scherrer Institut, Energy and Environment
Research Division, Villigen PSI CH-5232, Switzerland
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC-IIE, CH-1015 Lausanne, Switzerland
| | - Andrea Testino
- Paul Scherrer Institut, Energy and Environment
Research Division, Villigen PSI CH-5232, Switzerland
| | - Agnese Carino
- Paul Scherrer Institut, Energy and Environment
Research Division, Villigen PSI CH-5232, Switzerland
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC-IIE, CH-1015 Lausanne, Switzerland
| | - Christian Proff
- Paul Scherrer Institut, Energy and Environment
Research Division, Villigen PSI CH-5232, Switzerland
- Paul Scherrer Institut, Synchrotron Radiation
and Nanotechnology Research Department, Villigen PSI CH-5232, Switzerland
| | - Anastasios Kambolis
- Paul Scherrer Institut, Energy and Environment
Research Division, Villigen PSI CH-5232, Switzerland
- École Polytechnique Fédérale de Lausanne (EPFL), Institut des Sciences et Ingénierie Chimiques, CH-1015 Lausanne, Switzerland
| | - Antonio Cervellino
- Paul Scherrer Institut, Synchrotron Radiation
and Nanotechnology Research Department, Villigen PSI CH-5232, Switzerland
| | - Christian Ludwig
- Paul Scherrer Institut, Energy and Environment
Research Division, Villigen PSI CH-5232, Switzerland
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC-IIE, CH-1015 Lausanne, Switzerland
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31
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ZHANG M, MING Y, ZENG R, DING Z. Calculation of Bohmian quantum trajectories for STEM. J Microsc 2015; 260:200-7. [DOI: 10.1111/jmi.12283] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 06/07/2015] [Indexed: 11/30/2022]
Affiliation(s)
- M. ZHANG
- Department of Physics and Hefei National Laboratory for Physical Sciences at Microscale; University of Science and Technology of China; Hefei Anhui 230026 P.R. China
| | - Y. MING
- School of Physics and Material Science; Anhui University; Hefei Anhui 230601 P.R. China
| | - R.G. ZENG
- Science and Technology on Surface Physics and Chemistry Laboratory; Sichuan 621907 P.R China
| | - Z.J. DING
- Department of Physics and Hefei National Laboratory for Physical Sciences at Microscale; University of Science and Technology of China; Hefei Anhui 230026 P.R. China
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32
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Ciston J, Brown HG, D'Alfonso AJ, Koirala P, Ophus C, Lin Y, Suzuki Y, Inada H, Zhu Y, Allen LJ, Marks LD. Surface determination through atomically resolved secondary-electron imaging. Nat Commun 2015; 6:7358. [PMID: 26082275 PMCID: PMC4557350 DOI: 10.1038/ncomms8358] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/29/2015] [Indexed: 11/30/2022] Open
Abstract
Unique determination of the atomic structure of technologically relevant surfaces is often limited by both a need for homogeneous crystals and ambiguity of registration between the surface and bulk. Atomically resolved secondary-electron imaging is extremely sensitive to this registration and is compatible with faceted nanomaterials, but has not been previously utilized for surface structure determination. Here we report a detailed experimental atomic-resolution secondary-electron microscopy analysis of the c(6 × 2) reconstruction on strontium titanate (001) coupled with careful simulation of secondary-electron images, density functional theory calculations and surface monolayer-sensitive aberration-corrected plan-view high-resolution transmission electron microscopy. Our work reveals several unexpected findings, including an amended registry of the surface on the bulk and strontium atoms with unusual seven-fold coordination within a typically high surface coverage of square pyramidal TiO5 units. Dielectric screening is found to play a critical role in attenuating secondary-electron generation processes from valence orbitals.
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Affiliation(s)
- J. Ciston
- National Center for Electron Microscopy, The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - H. G. Brown
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - A. J. D'Alfonso
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - P. Koirala
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - C. Ophus
- National Center for Electron Microscopy, The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Y. Lin
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Y. Suzuki
- Application Development Department, Hitachi High Technologies Corp., Ibaraki 312-8504, Japan
| | - H. Inada
- Advanced Microscope Design Department, Hitachi High Technologies Corp., Ibaraki 312-8504, Japan
| | - Y. Zhu
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - L. J. Allen
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - L. D. Marks
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
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33
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Han CW, Ortalan V. Secondary signal imaging (SSI) electron tomography (SSI-ET): A new three-dimensional metrology for mesoscale specimens in transmission electron microscope. Micron 2015; 76:62-7. [PMID: 26072334 DOI: 10.1016/j.micron.2015.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/25/2015] [Accepted: 04/26/2015] [Indexed: 11/28/2022]
Abstract
We have demonstrated a new electron tomography technique utilizing the secondary signals (secondary electrons and backscattered electrons) for ultra thick (a few μm) specimens. The Monte Carlo electron scattering simulations reveal that the amount of backscattered electrons generated by 200 and 300keV incident electrons is a monotonic function of the sample thickness and this causes the thickness contrast satisfying the projection requirement for the tomographic reconstruction. Additional contribution of the secondary electrons emitted from the edges of the specimens enhances the visibility of the surface features. The acquired SSI tilt series of the specimen having mesoscopic dimensions are successfully reconstructed verifying that this new technique, so called the secondary signal imaging electron tomography (SSI-ET), can directly be utilized for 3D structural analysis of mesoscale structures.
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Affiliation(s)
- Chang Wan Han
- School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN, United States
| | - Volkan Ortalan
- School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN, United States.
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34
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Bischak CG, Hetherington CL, Wang Z, Precht JT, Kaz DM, Schlom DG, Ginsberg NS. Cathodoluminescence-activated nanoimaging: noninvasive near-field optical microscopy in an electron microscope. NANO LETTERS 2015; 15:3383-3390. [PMID: 25855869 DOI: 10.1021/acs.nanolett.5b00716] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate a new nanoimaging platform in which optical excitations generated by a low-energy electron beam in an ultrathin scintillator are used as a noninvasive, near-field optical scanning probe of an underlying sample. We obtain optical images of Al nanostructures with 46 nm resolution and validate the noninvasiveness of this approach by imaging a conjugated polymer film otherwise incompatible with electron microscopy due to electron-induced damage. The high resolution, speed, and noninvasiveness of this "cathodoluminescence-activated" platform also show promise for super-resolution bioimaging.
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Affiliation(s)
| | | | - Zhe Wang
- ⊥Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | | | | | - Darrell G Schlom
- ⊥Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- ¶Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States
| | - Naomi S Ginsberg
- ∇Kavli Energy NanoSciences Institute, University of California, Berkeley, California 94720, United States
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35
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Masters RC, Pearson AJ, Glen TS, Sasam FC, Li L, Dapor M, Donald AM, Lidzey DG, Rodenburg C. Sub-nanometre resolution imaging of polymer-fullerene photovoltaic blends using energy-filtered scanning electron microscopy. Nat Commun 2015; 6:6928. [PMID: 25906738 PMCID: PMC4423221 DOI: 10.1038/ncomms7928] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 03/16/2015] [Indexed: 12/02/2022] Open
Abstract
The resolution capability of the scanning electron microscope has increased immensely in recent years, and is now within the sub-nanometre range, at least for inorganic materials. An equivalent advance has not yet been achieved for imaging the morphologies of nanostructured organic materials, such as organic photovoltaic blends. Here we show that energy-selective secondary electron detection can be used to obtain high-contrast, material-specific images of an organic photovoltaic blend. We also find that we can differentiate mixed phases from pure material phases in our data. The lateral resolution demonstrated is twice that previously reported from secondary electron imaging. Our results suggest that our energy-filtered scanning electron microscopy approach will be able to make major inroads into the understanding of complex, nano-structured organic materials. Morphological characterization of organic photovoltaic active layers is restricted by the lack of accurate chemical mapping tools. Here, the authors demonstrate an energy-filtered scanning electron microscopy technique, which enables sub-nanometre resolution imaging of an organic photovoltaic blend.
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Affiliation(s)
- Robert C Masters
- Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, UK
| | - Andrew J Pearson
- Department of Physics, University of Cambridge, Cavendish Laboratory, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - Tom S Glen
- Department of Physics, University of Cambridge, Cavendish Laboratory, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - Fabian-Cyril Sasam
- FEI Co. Europe NanoPort, Achtseweg Noord 5, Eindhoven, 5651 GG, The Netherlands
| | - Letian Li
- FEI Co. Europe NanoPort, Achtseweg Noord 5, Eindhoven, 5651 GG, The Netherlands
| | - Maurizio Dapor
- European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*-FBK) and Trento Institute for Fundamental Physics and Applications (TIFPA-INFN), via Sommarive 18, Trento I-38123, Italy
| | - Athene M Donald
- Department of Physics, University of Cambridge, Cavendish Laboratory, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - David G Lidzey
- Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
| | - Cornelia Rodenburg
- Department of Materials Science and Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, UK
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36
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The correction of electron lens aberrations. Ultramicroscopy 2015; 156:A1-64. [PMID: 26025209 DOI: 10.1016/j.ultramic.2015.03.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 03/07/2015] [Accepted: 03/12/2015] [Indexed: 11/23/2022]
Abstract
The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague.
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37
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High Speed and Sensitive X-ray Analysis System with Automated Aberration Correction Scanning Transmission Electron Microscope. Appl Microsc 2015. [DOI: 10.9729/am.2015.45.1.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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38
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Ling L, Pan B, Zhang WX. Removal of selenium from water with nanoscale zero-valent iron: mechanisms of intraparticle reduction of Se(IV). WATER RESEARCH 2015; 71:274-281. [PMID: 25622004 DOI: 10.1016/j.watres.2015.01.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 01/01/2015] [Accepted: 01/03/2015] [Indexed: 06/04/2023]
Abstract
Increasing evidences suggest that nanoscale zero-valent iron (nZVI) is an effective agent for treatment and removal of selenium from water. For example, 1.3 mM selenite was quickly removed from water within 3 min with 5 g/L nZVI. In this work, reaction mechanisms of selenite [Se(IV)] in a single core-shell structured nanoscale zero-valent iron (nZVI) particle were studied with the method of spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) integrated with X-ray energy dispersive spectroscopy (XEDS). This method was utilized to visualize solid phase translocation and transformation of Se(IV) such as diffusion, reduction, deposition and the effect of surface defects in a single nanoparticle. Se(IV) was reduced to Se(-II) and Se(0), which then formed a 0.5 nm layer of selenium at the iron oxide-Fe(0) interface at a depth of 6 nm from the surface. The results provided near atomic-resolution proof on the intraparticle diffusion-reduction of Se(IV) induced by nZVI. The STEM mapping also discovered that defects on the surface layer accelerate the diffusion of selenium and increase the capacity of nZVI for selenium sequestration.
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Affiliation(s)
- Lan Ling
- State Key Laboratory of Pollution Control and Resource Reuse, PR China; College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Bingcai Pan
- State Key Laboratory of Pollution Control and Resource Reuse, PR China; School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China
| | - Wei-xian Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, PR China; College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
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39
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Bourke JD, Chantler CT. Momentum-Dependent Lifetime Broadening of Electron Energy Loss Spectra: A Self-Consistent Coupled-Plasmon Model. J Phys Chem Lett 2015; 6:314-9. [PMID: 26261939 DOI: 10.1021/jz5023812] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The complex dielectric function and associated energy loss spectrum of a condensed matter system is a fundamental material parameter that determines both the optical and electronic scattering behavior of the medium. The common representation of the electron energy loss function (ELF) is interpreted as the susceptibility of a system to a single- or bulk-electron (plasmon) excitation at a given energy and momentum and is commonly derived as a summation of noninteracting free-electron resonances with forms constrained by adherence to some externally determined optical standard. This work introduces a new causally constrained momentum-dependent broadening theory, permitting a more physical representation of optical and electronic resonances that agrees more closely with both optical attenuation and electron scattering data. We demonstrate how the momentum dependence of excitation resonances may be constrained uniquely by utilizing a coupled-plasmon model, in which high-energy excitations are able to relax into lower-energy excitations within the medium. This enables a robust and fully self-consistent theory with no free or fitted parameters that reveals additional physical insight not present in previous work. The new developments are applied to the scattering behavior of solid molybdenum and aluminum. We find that plasmon and single-electron lifetimes are significantly affected by the presence of alternate excitation channels and show for molybdenum that agreement with high-precision electron inelastic mean free path data is dramatically improved for energies above 20 eV.
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Affiliation(s)
- J D Bourke
- School of Physics, University of Melbourne, Parkville, Victoria 3010 Australia
| | - C T Chantler
- School of Physics, University of Melbourne, Parkville, Victoria 3010 Australia
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40
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Ruan Z, Zeng RG, Ming Y, Zhang M, Da B, Mao SF, Ding ZJ. Quantum-trajectory Monte Carlo method for study of electron–crystal interaction in STEM. Phys Chem Chem Phys 2015; 17:17628-37. [DOI: 10.1039/c5cp02300a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A quantum trajectory Monte Carlo method is developed to simulate electron scattering and secondary electron cascade process in crystalline specimen.
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Affiliation(s)
- Z. Ruan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics
- University of Science and Technology of China
- Hefei
- P. R. China
| | - R. G. Zeng
- Science and Technology on Surface Physics and Chemistry Laboratory
- Mianyang
- P. R. China
| | - Y. Ming
- School of Physics and Material Science
- Anhui University
- Hefei
- P. R. China
| | - M. Zhang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics
- University of Science and Technology of China
- Hefei
- P. R. China
| | - B. Da
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics
- University of Science and Technology of China
- Hefei
- P. R. China
| | - S. F. Mao
- School of Nuclear Science and Technology
- University of Science and Technology of China
- Hefei
- P. R. China
| | - Z. J. Ding
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics
- University of Science and Technology of China
- Hefei
- P. R. China
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41
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Zhang W, Zheng WT. Transmission electron microscopy finds plenty of room on the surface. Phys Chem Chem Phys 2015; 17:14461-9. [DOI: 10.1039/c5cp01705j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The merit of transmission electron microscopy is unraveled for the key progress, emerging opportunities and fascinating perspectives in surface exploration.
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Affiliation(s)
- Wei Zhang
- Department of Materials Science, and Key Laboratory of Mobile Materials MOE, and State Key Laboratory of Superhard Materials
- Jilin University
- Changchun 130012
- China
| | - Wei Tao Zheng
- Department of Materials Science, and Key Laboratory of Mobile Materials MOE, and State Key Laboratory of Superhard Materials
- Jilin University
- Changchun 130012
- China
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42
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Howe JY, Allard LF, Bigelow WC, Demers H, Overbury SH. Understanding catalyst behavior during in situ heating through simultaneous secondary and transmitted electron imaging. NANOSCALE RESEARCH LETTERS 2014; 9:614. [PMID: 25419195 PMCID: PMC4236855 DOI: 10.1186/1556-276x-9-614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 11/03/2014] [Indexed: 06/04/2023]
Abstract
By coupling techniques of simultaneous secondary (SE) and transmitted electron (TE) imaging at high resolution in a modern scanning transmission electron microscope (STEM), with the ability to heat specimens using a highly stable MEMS-based heating platform, we obtained synergistic information to clarify the behavior of catalysts during in situ thermal treatments. Au/iron oxide catalyst 'leached' to remove surface Au was heated to temperatures as high as 700°C. The Fe2O3 support particle structure tended to reduce to Fe3O4 and formed surface terraces; the formation, coalescence, and mobility of 1- to 2-nm particles on the terraces were characterized in SE, STEM-ADF, and TEM-BF modes. If combined with simultaneous nanoprobe spectroscopy, this approach will open the door to a new way of studying the kinetics of nano-scaled phenomena.
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Affiliation(s)
- Jane Y Howe
- Physical Sciences Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Rd, TN 37831 Oak Ridge, USA
- Hitachi High-Technologies Canada Inc, 89 Galaxy Blvd, Toronto, ON M9W 6A4, Canada
| | - Lawrence F Allard
- Physical Sciences Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Rd, TN 37831 Oak Ridge, USA
| | - Wilbur C Bigelow
- Department of Materials Science and Engineering, University of Michigan, 1221 Beal Avenue, Ann Arbor, MI 48104, USA
| | - Hendrix Demers
- Department of Mining and Materials Engineering, McGill University, 845 Rue Sherbrooke Ouest, Montreal, QC H3A 2B2, Canada
| | - Steven H Overbury
- Physical Sciences Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Rd, TN 37831 Oak Ridge, USA
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43
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Manfrinato VR, Wen J, Zhang L, Yang Y, Hobbs RG, Baker B, Su D, Zakharov D, Zaluzec NJ, Miller DJ, Stach EA, Berggren KK. Determining the resolution limits of electron-beam lithography: direct measurement of the point-spread function. NANO LETTERS 2014; 14:4406-12. [PMID: 24960635 DOI: 10.1021/nl5013773] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
One challenge existing since the invention of electron-beam lithography (EBL) is understanding the exposure mechanisms that limit the resolution of EBL. To overcome this challenge, we need to understand the spatial distribution of energy density deposited in the resist, that is, the point-spread function (PSF). During EBL exposure, the processes of electron scattering, phonon, photon, plasmon, and electron emission in the resist are combined, which complicates the analysis of the EBL PSF. Here, we show the measurement of delocalized energy transfer in EBL exposure by using chromatic aberration-corrected energy-filtered transmission electron microscopy (EFTEM) at the sub-10 nm scale. We have defined the role of spot size, electron scattering, secondary electrons, and volume plasmons in the lithographic PSF by performing EFTEM, momentum-resolved electron energy loss spectroscopy (EELS), sub-10 nm EBL, and Monte Carlo simulations. We expect that these results will enable alternative ways to improve the resolution limit of EBL. Furthermore, our approach to study the resolution limits of EBL may be applied to other lithographic techniques where electrons also play a key role in resist exposure, such as ion-beam-, X-ray-, and extreme-ultraviolet lithography.
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Affiliation(s)
- Vitor R Manfrinato
- Electrical Engineering and Computer Science Department, MIT , Cambridge, Massachusetts 02139, United States
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44
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Ling L, Zhang WX. Structures of Pd–Fe(0) bimetallic nanoparticles near 0.1 nm resolution. RSC Adv 2014. [DOI: 10.1039/c4ra04311a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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45
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He K, Zhou Y, Gao P, Wang L, Pereira N, Amatucci GG, Nam KW, Yang XQ, Zhu Y, Wang F, Su D. Sodiation via heterogeneous disproportionation in FeF2 electrodes for sodium-ion batteries. ACS NANO 2014; 8:7251-7259. [PMID: 24911154 DOI: 10.1021/nn502284y] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Sodium-ion batteries utilize various electrode materials derived from lithium batteries. However, the different characteristics inherent in sodium may cause unexpected cell reactions and battery performance. Thus, identifying the reactive discrepancy between sodiation and lithiation is essential for fundamental understanding and practical engineering of battery materials. Here we reveal a heterogeneous sodiation mechanism of iron fluoride (FeF2) nanoparticle electrodes by combining in situ/ex situ microscopy and spectroscopy techniques. In contrast to direct one-step conversion reaction with lithium, the sodiation of FeF2 proceeds via a regular conversion on the surface and a disproportionation reaction in the core, generating a composite structure of 1-4 nm ultrafine Fe nanocrystallites (further fused into conductive frameworks) mixed with an unexpected Na3FeF6 phase and a NaF phase in the shell. These findings demonstrate a core-shell reaction mode of the sodiation process and shed light on the mechanistic understanding extended to generic electrode materials for both Li- and Na-ion batteries.
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Affiliation(s)
- Kai He
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
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46
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Ruan Z, Zhang M, Zeng RG, Ming Y, Da B, Mao SF, Ding ZJ. Simulation study of the atomic resolution secondary electron imaging. SURF INTERFACE ANAL 2014. [DOI: 10.1002/sia.5565] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Z. Ruan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics; University of Science and Technology of China; Hefei Anhui 230026 PR China
| | - M. Zhang
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics; University of Science and Technology of China; Hefei Anhui 230026 PR China
| | - R. G. Zeng
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics; University of Science and Technology of China; Hefei Anhui 230026 PR China
| | - Y. Ming
- School of Physics and Material Science; Anhui University; Hefei Anhui 230601 PR China
| | - B. Da
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics; University of Science and Technology of China; Hefei Anhui 230026 PR China
| | - S. F. Mao
- School of Nuclear Science and Technology; University of Science and Technology of China; Hefei Anhui 230026 PR China
| | - Z. J. Ding
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics; University of Science and Technology of China; Hefei Anhui 230026 PR China
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47
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Akima H, Yoshida T. Measurement of large low-order aberrations by using a series of through-focus Ronchigrams. Microscopy (Oxf) 2014; 63:325-32. [PMID: 24740798 DOI: 10.1093/jmicro/dfu010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A method for measuring large aberrations up to second order (defocus, 2-fold astigmatism and axial coma), which uses a through-focus series of Ronchigrams, is proposed. The method is based on the principle that line-focus conditions in Ronchigrams can be locally detected and low-order aberrations can thereby be measured. The proposed method provides auto-tuning of large low-order aberration; in particular, iterative aberration measurement and correction reduce low-order aberrations from several thousand nanometers to less than a few hundred nanometers, which can be handled by conventional fine-aberration tuning methods.
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Affiliation(s)
- Hisanao Akima
- Central Research Laboratory, Hitachi, Ltd, 1-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo 185-8601, Japan Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Takaho Yoshida
- Central Research Laboratory, Hitachi, Ltd, 1-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo 185-8601, Japan
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48
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Lin Y, Wu Z, Wen J, Poeppelmeier KR, Marks LD. Imaging the atomic surface structures of CeO2 nanoparticles. NANO LETTERS 2014; 14:191-6. [PMID: 24295383 DOI: 10.1021/nl403713b] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Atomic surface structures of CeO2 nanoparticles are under debate owing to the lack of clear experimental determination of the oxygen atom positions. In this study, with oxygen atoms clearly observed using aberration-corrected high-resolution electron microscopy, we determined the atomic structures of the (100), (110), and (111) surfaces of CeO2 nanocubes. The predominantly exposed (100) surface has a mixture of Ce, O, and reduced CeO terminations, underscoring the complex structures of this polar surface that previously was often oversimplified. The (110) surface shows "sawtooth-like" (111) nanofacets and flat CeO2-x terminations with oxygen vacancies. The (111) surface has an O termination. These findings can be extended to the surfaces of differently shaped CeO2 nanoparticles and provide insight about face-selective catalysis.
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Affiliation(s)
- Yuyuan Lin
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
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49
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Abstract
In this chapter we describe three different approaches for three-dimensional imaging of electron microscopic samples: serial sectioning transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) tomography, and focused ion beam/scanning electron microscopy (FIB/SEM) tomography. With these methods, relatively large volumes of resin-embedded biological structures can be analyzed at resolutions of a few nm within a reasonable expenditure of time. The traditional method is serial sectioning and imaging the same area in all sections. Another method is TEM tomography that involves tilting a section in the electron beam and then reconstruction of the volume by back projection of the images. When the scanning transmission (STEM) mode is used, thicker sections (up to 1 μm) can be analyzed. The third approach presented here is focused ion beam/scanning electron microscopy (FIB/SEM) tomography, in which a sample is repeatedly milled with a focused ion beam (FIB) and each newly produced block face is imaged with the scanning electron microscope (SEM). This process can be repeated ad libitum in arbitrary small increments allowing 3D analysis of relatively large volumes such as eukaryotic cells. We show that resolution of this approach is considerably improved when the secondary electron signal is used. However, the most important prerequisite for three-dimensional imaging is good specimen preparation. For all three imaging methods, cryo-fixed (high-pressure frozen) and freeze-substituted samples have been used.
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50
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Wang F, Wu L, Ma C, Su D, Zhu Y, Graetz J. Excess lithium storage and charge compensation in nanoscale Li(4+x)Ti5O12. NANOTECHNOLOGY 2013; 24:424006. [PMID: 24067496 DOI: 10.1088/0957-4484/24/42/424006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Lithium titanate spinel (Li4Ti5O12; LTO) is a promising candidate for anodes in lithium-ion batteries due to its excellent cyclability and safety performance, and has been known as a 'zero-strain' material that allows reversible lithium insertion-deinsertion with little change in the lattice parameters. For a better understanding of lithium reaction mechanisms in this material, it has been of great interest to identify where lithium is inserted and how it migrates during charge and discharge, which is often difficult with x-ray and electron scattering techniques due to the low scattering power of lithium. In this study, we employed atomic-resolution annular bright-field imaging to directly image the lithium on interstitial sites in nanoscale LTO, and electron energy-loss spectroscopy to measure local lithium occupancy and electronic structure at different states of charge. During lithiation, charge compensation occurs primarily at O sites, rather than at Ti sites, and no significant change was found in the projected density of states (Ti 3d) until the voltage was lowered to ~50 mV or below. The Li K-edge spectra were simulated via ab initio calculations, providing a direct correlation between the near-edge fine structure and the local lithium coordination. During the initial states of discharge, lithium ions on 8a sites migrate to 16c sites (above 740 mV). Further lithiation causes the partial re-occupation of 8a sites, initially in the near-surface region at ~600 mV, and then in the bulk at lower voltages (~50 mV). We attribute the enhanced capacity in nanostructured LTO to extra storage of lithium in the near-surface region, primarily at {111} facets.
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Affiliation(s)
- Feng Wang
- Brookhaven National Laboratory, Upton, NY 11973, USA
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