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Makgae O, Moya A, Phaahlamohlaka T, Huang C, Coville N, Kirkland A, Liberti E. Direct visualisation of the surface atomic active sites of carbon-supported Co3O4 nanocrystals via high-resolution phase restoration. Chemphyschem 2022; 23:e202200031. [PMID: 35476226 PMCID: PMC9401059 DOI: 10.1002/cphc.202200031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/04/2022] [Indexed: 11/30/2022]
Abstract
The atomic arrangement of the terminating facets on spinel Co3O4 nanocrystals is strongly linked to their catalytic performance. However, the spinel crystal structure offers multiple possible surface terminations depending on the synthesis. Thus, understanding the terminating surface atomic structure is essential in developing high‐performance Co3O4 nanocrystals. In this work, we present direct atomic‐scale observation of the surface terminations of Co3O4 nanoparticles supported on hollow carbon spheres (HCSs) using exit wavefunction reconstruction from aberration‐corrected transmission electron microscopy focal‐series. The restored high‐resolution phases show distinct resolved oxygen and cobalt atomic columns. The data show that the structure of {100}, {110}, and {111} facets of spinel Co3O4 exhibit characteristic active sites for carbon monoxide (CO) adsorption, in agreement with density functional theory calculations. Of these facets, the {100} and {110} surface terminations are better suited for CO adsorption than the {111}. However, the presence of oxygen on the {111} surface termination indicates this facet also plays an essential role in CO adsorption. Our results demonstrate direct evidence of the surface termination atomic structure beyond the assumed stoichiometry of the surface.
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Affiliation(s)
- Ofentse Makgae
- Lund University, Centre for Analysis and Synthesis, Naturvetarvägen 14, P.O. Box 124, 221 00, Lund, SWEDEN
| | - Arthur Moya
- Oxford University: University of Oxford, Materials, UNITED KINGDOM
| | | | - Chen Huang
- Oxford University: University of Oxford, Materials, UNITED KINGDOM
| | - Neil Coville
- Wits University: University of the Witwatersrand, chemistry, School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa, 2050, Johannesburg, South Africa, SOUTH AFRICA
| | - Angus Kirkland
- Oxford University: University of Oxford, Materials, 16 Parks Road, Oxford, University of Oxford, Oxford, OX1 3PH, Oxford, UNITED KINGDOM
| | - Emanuela Liberti
- Oxford University: University of Oxford, Materials, UNITED KINGDOM
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Direct estimation and correction of residual aberrations in the reconstructed exit-wavefunction of a crystalline specimen. Micron 2022; 157:103247. [DOI: 10.1016/j.micron.2022.103247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 11/18/2022]
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Yoon A, Shao YT, Howe J, Zuo JM. Electron image contrast analysis of mosaicity in rutile nanocrystals using direct electron detection. Acta Crystallogr A Found Adv 2020; 76:687-697. [DOI: 10.1107/s2053273320011055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 08/11/2020] [Indexed: 11/10/2022] Open
Abstract
Direct electron detection provides high detective quantum efficiency, significantly improved point spread function and fast read-out which have revolutionized the field of cryogenic electron microscopy. However, these benefits for high-resolution electron microscopy (HREM) are much less exploited, especially for in situ study where major impacts on crystallographic structural studies could be made. By using direct detection in electron counting mode, rutile nanocrystals have been imaged at high temperature inside an environmental transmission electron microscope. The improvements in image contrast are quantified by comparison with a charge-coupled device (CCD) camera and by image matching with simulations using an automated approach based on template matching. Together, these approaches enable a direct measurement of 3D shape and mosaicity (∼1°) of a vacuum-reduced TiO2 nanocrystal about 50 nm in size. Thus, this work demonstrates the possibility of quantitative HREM image analysis based on direct electron detection.
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Luo C, Wang C, Wu X, Zhang J, Chu J. In Situ Transmission Electron Microscopy Characterization and Manipulation of Two-Dimensional Layered Materials beyond Graphene. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1604259. [PMID: 28783241 DOI: 10.1002/smll.201604259] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 06/22/2017] [Indexed: 06/07/2023]
Abstract
Two-dimensional (2D) ultra-thin materials beyond graphene with rich physical properties and unique layered structures are promising for applications in electronics, chemistry, energy, and bioscience, etc. The interaction mechanisms among the structures, chemical compositions and physical properties of 2D layered materials are critical for fundamental nanosciences and the practical fabrication of next-generation nanodevices. Transmission electron microscopy (TEM), with its high spatial resolution and versatile external fields, is undoubtedly a powerful tool for the static characterization and dynamic manipulation of nanomaterials and nanodevices at the atomic scale. The rapid development of thin-film and precision microelectromechanical systems (MEMS) techniques allows 2D layered materials and nanodevices to be probed and engineered inside TEM under external stimuli such as thermal, electrical, mechanical, liquid/gas environmental, optical, and magnetic fields at the nanoscale. Such advanced technologies leverage the traditional static TEM characterization into an in situ and interactive manipulation of 2D layered materials without sacrificing the resolution or the high vacuum chamber environment, facilitating exploration of the intrinsic structure-property relationship of 2D layered materials. In this Review, the dynamic properties tailored and observed by the most advanced and unprecedented in situ TEM technology are introduced. The challenges in spatial, time and energy resolution are discussed also.
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Affiliation(s)
- Chen Luo
- Shanghai Key Laboratory of Multidimensional Information Processing, State Key Laboratory of Transducer Technology, Department of Electrical Engineering, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Chaolun Wang
- Shanghai Key Laboratory of Multidimensional Information Processing, State Key Laboratory of Transducer Technology, Department of Electrical Engineering, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Xing Wu
- Shanghai Key Laboratory of Multidimensional Information Processing, State Key Laboratory of Transducer Technology, Department of Electrical Engineering, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Jian Zhang
- Shanghai Key Laboratory of Multidimensional Information Processing, State Key Laboratory of Transducer Technology, Department of Electrical Engineering, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Junhao Chu
- Shanghai Key Laboratory of Multidimensional Information Processing, State Key Laboratory of Transducer Technology, Department of Electrical Engineering, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
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Wen C, Smith DJ. Impact of dynamical scattering on quantitative contrast for aberration-corrected transmission electron microscope images. Micron 2016; 89:77-86. [PMID: 27522350 DOI: 10.1016/j.micron.2016.07.008] [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: 06/15/2016] [Revised: 07/22/2016] [Accepted: 07/23/2016] [Indexed: 10/21/2022]
Abstract
Aberration-corrected transmission electron microscope images taken under optimum-defocus conditions or processed offline can correctly reflect the projected crystal structure with atomic resolution. However, dynamical scattering, which will seriously influence image contrast, is still unavoidable. Here, the multislice image simulation approach was used to quantify the impact of dynamical scattering on the contrast of aberration-corrected images for a 3C-SiC specimen with changes in atomic occupancy and thickness. Optimum-defocus images with different spherical aberration (CS) coefficients, and structure images restored by deconvolution processing, were studied. The results show that atomic-column positions and the atomic occupancy for SiC 'dumbbells' can be determined by analysis of image contrast profiles only below a certain thickness limit. This limit is larger for optimum-defocus and restored structure images with negative CS coefficient than those with positive CS coefficient. The image contrast of C (or Si) atomic columns with specific atomic occupancy changes differently with increasing crystal thickness. Furthermore, contrast peaks for C atomic columns overlapping with neighboring peaks of Si atomic columns with varied Si atomic occupancy, which is enhanced with increasing crystal thickness, can be neglected in restored structure images, but the effect is substantial in optimum-defocus images.
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Affiliation(s)
- C Wen
- School of Science, Southwest University of Science and Technology, Mianyang 621010, China; Department of Physics, Arizona State University, Tempe, AZ 85287, USA.
| | - David J Smith
- Department of Physics, Arizona State University, Tempe, AZ 85287, USA
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Ozsoy-Keskinbora C, Boothroyd CB, Dunin-Borkowski RE, van Aken PA, Koch CT. Mapping the electrostatic potential of Au nanoparticles using hybrid electron holography. Ultramicroscopy 2016; 165:8-14. [PMID: 27043767 DOI: 10.1016/j.ultramic.2016.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 03/18/2016] [Accepted: 03/23/2016] [Indexed: 11/19/2022]
Abstract
Electron holography is a powerful technique for characterizing electrostatic potentials, charge distributions, electric and magnetic fields, strain distributions and semiconductor dopant distributions with sub-nm spatial resolution. Mapping internal electrostatic and magnetic fields within nanoparticles and other low-dimensional materials by TEM requires both high spatial resolution and high phase sensitivity. Carrying out such an analysis fully quantitatively is even more challenging, since artefacts such as dynamical electron scattering may strongly affect the measurement. In-line electron holography, one of the variants of electron holography, features high phase sensitivity at high spatial frequencies, but suffers from inefficient phase recovery at low spatial frequencies. Off-axis electron holography, in contrast, can recover low spatial frequency phase information much more reliably, but is less effective in retrieving phase information at high spatial frequencies when compared to in-line holography. We investigate gold nanoparticles using hybrid electron holography at both atomic-resolution and intermediate magnification. Hybrid electron holography is a novel technique that synergistically combines off-axis and in-line electron holography, allowing the measurement of the complex wave function describing the scattered electrons with excellent signal-to-noise properties at both high and low spatial frequencies. The effect of dynamical electron scattering is minimized by beam tilt averaging.
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Affiliation(s)
- Cigdem Ozsoy-Keskinbora
- Stuttgart Center for Electron Microscopy, Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany.
| | - Chris B Boothroyd
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Peter A van Aken
- Stuttgart Center for Electron Microscopy, Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Christoph T Koch
- Structure Research & Electron Microscopy group, Department of Physics, Humboldt University of Berlin, Newtonstraße 15, 12489 Berlin, Germany
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8
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LUPINI A, CHI M, JESSE S. Rapid aberration measurement with pixelated detectors. J Microsc 2016; 263:43-50. [DOI: 10.1111/jmi.12372] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 11/28/2015] [Indexed: 10/22/2022]
Affiliation(s)
- A.R. LUPINI
- Materials Science & Technology Division; Oak Ridge National Laboratory; Oak Ridge Tennessee U.S.A
- Institute for Functional Imaging of Materials; Oak Ridge National Laboratory; Oak Ridge Tennessee U.S.A
| | - M. CHI
- Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge Tennessee U.S.A
| | - S. JESSE
- Center for Nanophase Materials Sciences; Oak Ridge National Laboratory; Oak Ridge Tennessee U.S.A
- Institute for Functional Imaging of Materials; Oak Ridge National Laboratory; Oak Ridge Tennessee U.S.A
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9
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Kirkland EJ. Computation in electron microscopy. ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 2016; 72:1-27. [DOI: 10.1107/s205327331501757x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/19/2015] [Indexed: 11/11/2022]
Abstract
Some uses of the computer and computation in high-resolution transmission electron microscopy are reviewed. The theory of image calculation using Bloch wave and multislice methods with and without aberration correction is reviewed and some applications are discussed. The inverse problem of reconstructing the specimen structure from an experimentally measured electron microscope image is discussed. Some future directions of software development are given.
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10
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Ishida T, Kawasaki T, Tanji T, Kodama T, Matsutani T, Ogai K, Ikuta T. Phase reconstruction in annular bright-field scanning transmission electron microscopy. Microscopy (Oxf) 2014; 64:69-76. [PMID: 25387907 DOI: 10.1093/jmicro/dfu098] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 10/07/2014] [Indexed: 11/14/2022] Open
Abstract
A novel technique for reconstructing the phase shifts of electron waves was applied to Cs-corrected scanning transmission electron microscopy (STEM). To realize this method, a new STEM system equipped with an annular aperture, annularly arrayed detectors and an arrayed image processor has been developed and evaluated in experiments. We show a reconstructed phase image of graphite particles and demonstrate that this new method works effectively for high-resolution phase imaging.
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Affiliation(s)
- Takafumi Ishida
- Department of Electrical Engineering and Computer Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan Global Research Center for Environment and Energy Based on Nanomaterials Science, Furo-cho, Chikusa, Nagoya 464-8502, Japan
| | - Tadahiro Kawasaki
- Global Research Center for Environment and Energy Based on Nanomaterials Science, Furo-cho, Chikusa, Nagoya 464-8502, Japan EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8502, Japan Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta, Nagoya 456-8587, Japan
| | - Takayoshi Tanji
- Global Research Center for Environment and Energy Based on Nanomaterials Science, Furo-cho, Chikusa, Nagoya 464-8502, Japan EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8502, Japan
| | - Tetsuji Kodama
- Department of Electrical and Electronic Engineering, Faculty of Science and Technology, Meijo University, 1-501 Shiogamaguchi, Tempaku, Nagoya 468-8502, Japan
| | - Takaomi Matsutani
- Department of Electrical and Electronic Engineering, Faculty of Science and Technology, Kinki University, 3-4-1 Kowakae, Higashiosaka 577-8502, Japan
| | - Keiko Ogai
- APCO Ltd., 522-10 Kitano-machi, Hachioji 192-0906, Japan
| | - Takashi Ikuta
- Department of Electrical and Electronic Engineering, Faculty of Engineering, Osaka Electro-Communication University, 18-8 Hatsu-cho, Neyagawa 572-8530, Japan
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11
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Huang C, Borisenko KB, Kirkland AI. Exit wave reconstruction of radiation-sensitive materials from low-dose data. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1742-6596/522/1/012052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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12
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Haigh S, Jiang B, Alloyeau D, Kisielowski C, Kirkland A. Recording low and high spatial frequencies in exit wave reconstructions. Ultramicroscopy 2013; 133:26-34. [DOI: 10.1016/j.ultramic.2013.04.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/18/2013] [Accepted: 04/30/2013] [Indexed: 10/26/2022]
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13
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Shmeliov A, Kim JS, Borisenko KB, Wang P, Okunishi E, Shannon M, Kirkland AI, Nellist PD, Nicolosi V. Impurity induced non-bulk stacking in chemically exfoliated h-BN nanosheets. NANOSCALE 2013; 5:2290-2294. [PMID: 23420037 DOI: 10.1039/c3nr33375b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Structural characterization of 2D nanomaterials is an important step towards their future applications. In this work we carried out imaging and structural analysis of 2D h-BN produced by chemical-exfoliation, emphasizing the stacking order in few-layer sheets. Our analysis, for the first time has shown conclusively that non-bulk stacking can exist in 2D h-BN.
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Affiliation(s)
- Aleksey Shmeliov
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
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14
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Texier M, Thibault-Pénisson J. Optimum correction conditions for aberration-corrected HRTEM SiC dumbbells chemical imaging. Micron 2012. [DOI: 10.1016/j.micron.2011.09.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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15
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De Backer A, Van Aert S, Van Dyck D. High precision measurements of atom column positions using model-based exit wave reconstruction. Ultramicroscopy 2011; 111:1475-82. [PMID: 21930019 DOI: 10.1016/j.ultramic.2011.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 07/06/2011] [Accepted: 07/14/2011] [Indexed: 11/29/2022]
Abstract
In this paper, it has been investigated how to measure atom column positions as accurately and precisely as possible using a focal series of images. In theory, it is expected that the precision would considerably improve using a maximum likelihood estimator based on the full series of focal images. As such, the theoretical lower bound on the variances of the unknown atom column positions can be attained. However, this approach is numerically demanding. Therefore, maximum likelihood estimation has been compared with the results obtained by fitting a model to a reconstructed exit wave rather than to the full series of focal images. Hence, a real space model-based exit wave reconstruction technique based on the channelling theory is introduced. Simulations show that the reconstructed complex exit wave contains the same amount of information concerning the atom column positions as the full series of focal images. Only for thin samples, which act as weak phase objects, this information can be retrieved from the phase of the reconstructed complex exit wave.
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Affiliation(s)
- A De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Belgium.
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Haigh SJ, Young NP, Sawada H, Takayanagi K, Kirkland AI. Imaging the Active Surfaces of Cerium Dioxide Nanoparticles. Chemphyschem 2011; 12:2397-9. [DOI: 10.1002/cphc.201100376] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Indexed: 11/11/2022]
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17
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Barthel J, Thust A. REPRINT OF: Aberration measurement in HRTEM: Implementation and diagnostic use of numerical procedures for the highly precise recognition of diffractogram patterns. Ultramicroscopy 2011; 111:920-39. [DOI: 10.1016/j.ultramic.2011.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 09/10/2010] [Accepted: 09/18/2010] [Indexed: 10/18/2022]
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18
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Kim JS, Borisenko KB, Nicolosi V, Kirkland AI. Controlled radiation damage and edge structures in boron nitride membranes. ACS NANO 2011; 5:3977-3986. [PMID: 21510623 DOI: 10.1021/nn2005443] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We show that hexagonal boron nitride membranes synthesized by chemical exfoliation are more resistant to electron beam irradiation at 80 kV than is graphene, consistent with quantum chemical calculations describing the radiation damage processes. Monolayer hexagonal boron nitride does not form vacancy defects or amorphize during extended electron beam irradiation. Zigzag edge structures are predominant in thin membranes for both a freestanding boron nitride monolayer and for a supported multilayer step edge. We have also determined that the elemental termination species in the zigzag edges is predominantly N.
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Affiliation(s)
- Judy S Kim
- Department of Materials, University of Oxford, Parks Road, Oxford OX13PH, U.K.
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19
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Barnard AS, Chang LY. Thermodynamic Cartography and Structure/Property Mapping of Commercial Platinum Catalysts. ACS Catal 2011. [DOI: 10.1021/cs100025y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amanda S. Barnard
- CSIRO Materials Science and Engineering, Clayton, Victoria, 3168 Australia and
| | - Lan Y. Chang
- Monash Centre for Electron Microscopy and School of Chemistry, Monash University, Clayton, Australia
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Barthel J, Thust A. Aberration measurement in HRTEM: Implementation and diagnostic use of numerical procedures for the highly precise recognition of diffractogram patterns. Ultramicroscopy 2010; 111:27-46. [DOI: 10.1016/j.ultramic.2010.09.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 09/10/2010] [Accepted: 09/18/2010] [Indexed: 10/19/2022]
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22
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Haigh SJ, Sawada H, Kirkland AI. Optimal tilt magnitude determination for aberration-corrected super resolution exit wave function reconstruction. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:3755-3771. [PMID: 19687064 DOI: 10.1098/rsta.2009.0124] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Transmission electron microscope (TEM) images recorded under tilted illumination conditions transfer higher spatial frequencies than axial images. This super resolution information transfer is highly directional in a single image, but can be extended in all directions through the use of complementary beam tilts during exit wave function reconstruction. We have determined the optimal experimental tilt magnitude for aperture synthesis in an aberration-corrected TEM. It is shown that electron-optical aberration correction allows the use of larger tilt angles and reduces the constraints that are imposed on experimental data acquisition in an uncorrected microscope. We demonstrate that, in many cases, the resolution improvement achievable is now limited by the sample and not by instrumental parameters. An exit wave function is presented that has been successfully reconstructed from a dataset of aberration-corrected images, including images acquired at a beam tilt of 18 mrad, which clearly demonstrates a resolution improvement from 0.11 nm to better than 0.08 nm at 200 kV.
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Affiliation(s)
- S J Haigh
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
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23
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Aert SV, Chang L, Bals S, Kirkland A, Tendeloo GV. Effect of amorphous layers on the interpretation of restored exit waves. Ultramicroscopy 2009; 109:237-46. [DOI: 10.1016/j.ultramic.2008.10.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 10/20/2008] [Accepted: 10/29/2008] [Indexed: 11/27/2022]
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24
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Sceats EL, Green ML, Kirkland AI, Green JC. DFT calculations of KI crystals formed within single-walled carbon nanotubes. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.10.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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25
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Kirkland AI, Haigh S, Chang LY. Aberration corrected TEM: current status and future prospects. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/126/1/012034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Hetherington CJD, Chang LYS, Haigh S, Nellist PD, Gontard LC, Dunin-Borkowski RE, Kirkland AI. High-resolution TEM and the application of direct and indirect aberration correction. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2008; 14:60-67. [PMID: 18171500 DOI: 10.1017/s1431927608080148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 08/07/2007] [Indexed: 05/25/2023]
Abstract
Aberration correction leads to a substantial improvement in the directly interpretable resolution of transmission electron microscopes. Correction of the aberrations has been achieved electron-optically through a hexapole-based corrector and also indirectly by computational analysis of a focal or tilt series of images. These direct and indirect methods are complementary, and a combination of the two offers further advantages. Materials characterization has benefitted from the reduced delocalization and higher resolution in the corrected images. It is now possible, for example, to locate atomic columns at surfaces to higher accuracy and reliability. This article describes the JEM-2200FS in Oxford, which is equipped with correctors for both the image-forming and probe-forming lenses. Examples of the use of this instrument in the characterization of nanocrystalline catalysts are given together with initial results combining direct and indirect methods. The double corrector configuration enables direct imaging of the corrected probe, and a potential confocal imaging mode is described. Finally, modifications to a second generation instrument are outlined.
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28
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Smith DJ. Development of aberration-corrected electron microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2008; 14:2-15. [PMID: 18171498 DOI: 10.1017/s1431927608080124] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2007] [Accepted: 08/07/2007] [Indexed: 05/25/2023]
Abstract
The successful correction of spherical aberration is an exciting and revolutionary development for the whole field of electron microscopy. Image interpretability can be extended out to sub-Angstrom levels, thereby creating many novel opportunities for materials characterization. Correction of lens aberrations involves either direct (online) hardware attachments in fixed-beam or scanning TEM or indirect (off-line) software processing using either off-axis electron holography or focal-series reconstruction. This review traces some of the important steps along the path to realizing aberration correction, including early attempts with hardware correctors, the development of online microscope control, and methods for accurate measurement of aberrations. Recent developments and some initial applications of aberration-corrected electron microscopy using these different approaches are surveyed. Finally, future prospects and problems are briefly discussed.
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Affiliation(s)
- David J Smith
- Department of Physics, Arizona State University, Tempe, Arizona 85287-1504, USA.
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Meurig Thomas J, Adams RD, Boswell EM, Captain B, Grönbeck H, Raja R. Synthesis, characterization, electronic structure and catalytic performance of bimetallic and trimetallic nanoparticles containing tin. Faraday Discuss 2008; 138:301-15; discussion 317-35, 433-4. [DOI: 10.1039/b706151j] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kirkland A, Sloan J, Haigh S. Ultrahigh resolution imaging of local structural distortions in intergrowth tungsten bronzes. Ultramicroscopy 2007; 107:501-6. [DOI: 10.1016/j.ultramic.2006.03.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Accepted: 03/10/2006] [Indexed: 11/17/2022]
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Gontard L, Chang LY, Hetherington C, Kirkland A, Ozkaya D, Dunin-Borkowski R. Aberration-Corrected Imaging of Active Sites on Industrial Catalyst Nanoparticles. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604811] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gontard LC, Chang LY, Hetherington CJD, Kirkland AI, Ozkaya D, Dunin-Borkowski RE. Aberration-Corrected Imaging of Active Sites on Industrial Catalyst Nanoparticles. Angew Chem Int Ed Engl 2007; 46:3683-5. [PMID: 17387674 DOI: 10.1002/anie.200604811] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lionel Cervera Gontard
- Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, UK
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Hirahara K, Saitoh K, Yamasaki J, Tanaka N. Direct observation of six-membered rings in the upper and lower walls of a single-wall carbon nanotube by spherical aberration-corrected HRTEM. NANO LETTERS 2006; 6:1778-83. [PMID: 16895373 DOI: 10.1021/nl060458k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Atomic arrangements of the continuous network of six-membered rings in a single graphene sheet constituting a single-wall carbon nanotube was imaged successfully by employing a spherical aberration-corrected HRTEM operated at 120 kV acceleration voltage. Utilizing two advantages of the aberration-corrected HRTEM, the images separately resolved the rings in the upper and lower walls. Such images can be considered to be the first "tomographic" atomic images taken by HRTEM. This is a striking result that changes the conventional concept of HRTEM as a projection image.
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Affiliation(s)
- Kaori Hirahara
- EcoTopia Science Institute, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan.
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Lovely GR, Brown AP, Brydson R, Kirkland AI, Meyer RR, Chang LY, Jefferson DA, Falke M, Bleloch A. HREM of the {111} surfaces of iron oxide nanoparticles. Micron 2006; 37:389-95. [PMID: 16563776 DOI: 10.1016/j.micron.2006.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Mixed phase Fe3O4-gamma-Fe2O3 (magnetite-maghemite) iron oxide nanoparticles have been fabricated by colloidal routes. HRTEM/HRSTEM images of the nanoparticles show the presence of [111] facets that terminate with enhanced contrast, which is shown to be caused by the presence of additional cations at the edges of the nanoparticles. HRTEM images were taken on a FEI CM200 FEGTEM, a JEOL 3100 with a LaB6 source, and a double aberration corrected JEOL-JEM 2200FS FEGTEM. The enhanced contrast effect was observed on the [111] surface atomic layers resolved using each machine. HRSTEM images, taken on an aberration corrected STEM, resolved enhanced contrast at specific surface sites. Exit wave reconstruction was also carried out on focal series taken on a double aberration corrected JEOL-JEM 2200FS and showed similar highly resolved enhanced contrast at specific surface cation sites. It is apparent that additional cations are occupying the [111] terminating layers of these nanoparticle surfaces. The use of different microscopes and techniques in this paper provides strong evidence that the enhanced contrast is a real effect and not an effect caused by microscope aberrations.
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Affiliation(s)
- G R Lovely
- Institute for Materials Research, University of Leeds, Leeds LS2 9JT, UK
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Carter R, Sloan J, Kirkland AI, Meyer RR, Lindan PJD, Lin G, Green MLH, Vlandas A, Hutchison JL, Harding J. Correlation of structural and electronic properties in a new low-dimensional form of mercury telluride. PHYSICAL REVIEW LETTERS 2006; 96:215501. [PMID: 16803245 DOI: 10.1103/physrevlett.96.215501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Indexed: 05/06/2023]
Abstract
Using high resolution electron microscopy and first principles quantum mechanical calculations we have explored the fundamental physics and chemistry of the semiconductor, HgTe grown inside single wall carbon nanotubes. This material forms a low-dimensional structure based on a repeating Hg2Te2 motif in which both atom species adopt new coordination geometries not seen in the bulk. Density-functional theory calculations confirm the stability of this structure and demonstrate conclusively that it arises solely as a consequence of constrained low dimensionality. This change is directly correlated with a modified electronic structure in which the low-dimensional form of HgTe is transformed from a bulk semimetal to a semiconductor.
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Affiliation(s)
- Robin Carter
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
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Lovely GR, Brown AP, Brydson R, Kirkland AI, Meyer R, Chang LY, Jefferson DA, Falke M, Bleloch A. HREM of metallized {111} iron oxide nanoparticle surfaces. ACTA ACUST UNITED AC 2006. [DOI: 10.1088/1742-6596/26/1/045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kirkland AI, Meyer RR, Sloan J, Hutchison JL. Structure determination of atomically controlled crystal architectures grown within single wall carbon nanotubes. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2005; 11:401-9. [PMID: 17481321 DOI: 10.1017/s1431927605050385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Accepted: 05/26/2004] [Indexed: 05/06/2023]
Abstract
Indirect high resolution electron microscopy using one of several possible data-set geometries offers advantages over conventional high-resolution imaging in enabling the recovery of the complex wavefunction at the specimen exit plane and simultaneously eliminating the aberrations present in the objective lens. This article discusses results obtained using this method from structures formed by inorganic materials confined within the bores of carbon nanotubes. Such materials are shown to be atomically regulated due to their confinement, leading to integral layer architectures that we have termed "Feynman crystals." These one-dimensional (1D) crystals also show a wide range of structural deviations from the bulk, including unexpected lattice distortions, and in some cases entirely new forms have been observed.
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Affiliation(s)
- Angus I Kirkland
- University of Oxford, Department of Materials, Parks Road, Oxford OX1 3PH, UK.
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