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Optimal acceleration voltage for near-atomic resolution imaging of layer-stacked 2D polymer thin films. Nat Commun 2022; 13:3948. [PMID: 35803950 PMCID: PMC9270374 DOI: 10.1038/s41467-022-31688-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 06/29/2022] [Indexed: 11/29/2022] Open
Abstract
Despite superb instrumental resolution in modern transmission electron microscopes (TEM), high-resolution imaging of organic two-dimensional (2D) materials is a formidable task. Here, we present that the appropriate selection of the incident electron energy plays a crucial role in reducing the gap between achievable resolution in the image and the instrumental limit. Among a broad range of electron acceleration voltages (300 kV, 200 kV, 120 kV, and 80 kV) tested, we found that the highest resolution in the HRTEM image is achieved at 120 kV, which is 1.9 Å. In two imine-based 2D polymer thin films, unexpected molecular interstitial defects were unraveled. Their structural nature is identified with the aid of quantum mechanical calculations. Furthermore, the increased image resolution and enhanced image contrast at 120 kV enabled the detection of functional groups at the pore interfaces. The experimental setup has also been employed for an amorphous organic 2D material. High-resolution imaging of organic 2D materials using transmission electron microscopes is challenging. Here, the authors find the optimal electron acceleration voltage, and demonstrate 1.9 Å resolution, enabling detection of interstitial defects and functional groups in 2D polymer thin films.
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Piao H, Choi G, Jin X, Hwang SJ, Song YJ, Cho SP, Choy JH. Monolayer Graphitic Carbon Nitride as Metal-Free Catalyst with Enhanced Performance in Photo- and Electro-Catalysis. NANO-MICRO LETTERS 2022; 14:55. [PMID: 35113289 PMCID: PMC8814173 DOI: 10.1007/s40820-022-00794-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 12/28/2021] [Indexed: 05/09/2023]
Abstract
The g-C3N4 monolayer in the perfect 2D limit was successfully realized, for the first time, by the well-defined chemical strategy based on the bottom-up process. The most striking evidence was made from Cs-high resolution transmission electron microscopy measurements by observing directly the atomic structure of g-C3N4 unit cell, which was again supported by the corresponding high resolution transmission electron microscopy image simulation results. We demonstrated that the newly prepared g-C3N4 monolayer showed outstanding photocatalytic activity for H2O2 generation as well as excellent electrocatalytic activity for oxygen reduction reaction. The exfoliation of bulk graphitic carbon nitride (g-C3N4) into monolayer has been intensively studied to induce maximum surface area for fundamental studies, but ended in failure to realize chemically and physically well-defined monolayer of g-C3N4 mostly due to the difficulty in reducing the layer thickness down to an atomic level. It has, therefore, remained as a challenging issue in two-dimensional (2D) chemistry and physics communities. In this study, an "atomic monolayer of g-C3N4 with perfect two-dimensional limit" was successfully prepared by the chemically well-defined two-step routes. The atomically resolved monolayer of g-C3N4 was also confirmed by spectroscopic and microscopic analyses. In addition, the experimental Cs-HRTEM image was collected, for the first time, which was in excellent agreement with the theoretically simulated; the evidence of monolayer of g-C3N4 in the perfect 2D limit becomes now clear from the HRTEM image of orderly hexagonal symmetry with a cavity formed by encirclement of three adjacent heptazine units. Compared to bulk g-C3N4, the present g-C3N4 monolayer showed significantly higher photocatalytic generation of H2O2 and H2, and electrocatalytic oxygen reduction reaction. In addition, its photocatalytic efficiency for H2O2 production was found to be the best for any known g-C3N4 nanomaterials, underscoring the remarkable advantage of monolayer formation in optimizing the catalyst performance of g-C3N4.
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Affiliation(s)
- Huiyan Piao
- Intelligent Nanohybrid Materials Laboratory (INML), Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea
| | - Goeun Choi
- Intelligent Nanohybrid Materials Laboratory (INML), Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea
- College of Science and Technology, Dankook University, Cheonan, 31116, Republic of Korea
- Department of Nanobiomedical Science and BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Xiaoyan Jin
- Department of Materials Science and Engineering, College of Engineering, Yonsei University, Seoul, 03722, Republic of Korea
| | - Seong-Ju Hwang
- Department of Materials Science and Engineering, College of Engineering, Yonsei University, Seoul, 03722, Republic of Korea
| | - Young Jae Song
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea
- Department of Nano Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea
| | - Sung-Pyo Cho
- National Center for Inter-University Research Facilities (NCIRF), Seoul National University, Seoul, 08826, Republic of Korea.
- Graphene Research Center, Advanced Institute of Convergence Technology, Suwon, 16229, Republic of Korea.
| | - Jin-Ho Choy
- Intelligent Nanohybrid Materials Laboratory (INML), Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea.
- Department of Pre-Medical Course, College of Medicine, Dankook University, Cheonan, 31116, Republic of Korea.
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 226-8503, Japan.
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Mzyk A, Ong Y, Ortiz Moreno AR, Padamati SK, Zhang Y, Reyes-San-Martin CA, Schirhagl R. Diamond Color Centers in Diamonds for Chemical and Biochemical Analysis and Visualization. Anal Chem 2022; 94:225-249. [PMID: 34841868 DOI: 10.1021/acs.analchem.1c04536] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Aldona Mzyk
- University Medical Center Groningen, Groningen University, Antonius Deusinglaan 1, 9713 AW Groningen, The Netherlands
- Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Reymonta 25, 30-059 Krakow, Poland
| | - Yori Ong
- University Medical Center Groningen, Groningen University, Antonius Deusinglaan 1, 9713 AW Groningen, The Netherlands
| | - Ari R Ortiz Moreno
- University Medical Center Groningen, Groningen University, Antonius Deusinglaan 1, 9713 AW Groningen, The Netherlands
| | - Sandeep K Padamati
- University Medical Center Groningen, Groningen University, Antonius Deusinglaan 1, 9713 AW Groningen, The Netherlands
| | - Yue Zhang
- University Medical Center Groningen, Groningen University, Antonius Deusinglaan 1, 9713 AW Groningen, The Netherlands
| | - Claudia A Reyes-San-Martin
- University Medical Center Groningen, Groningen University, Antonius Deusinglaan 1, 9713 AW Groningen, The Netherlands
| | - Romana Schirhagl
- University Medical Center Groningen, Groningen University, Antonius Deusinglaan 1, 9713 AW Groningen, The Netherlands
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Mendes RG, Ta HQ, Yang X, Bachmatiuk A, Praus P, Mamakhel A, Iversen BB, Su R, Gemming T, Rümmeli MH. Tailoring the stoichiometry of C 3N 4 nanosheets under electron beam irradiation. Phys Chem Chem Phys 2021; 23:4747-4756. [PMID: 33599219 DOI: 10.1039/d0cp06518h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-dimensional polymeric graphitic carbon nitride (g-C3N4) is a low-cost material with versatile properties that can be enhanced by the introduction of dopant atoms and by changing the degree of polymerization/stoichiometry, which offers significant benefits for numerous applications. Herein, we investigate the stability of g-C3N4 under electron beam irradiation inside a transmission electron microscope operating at different electron acceleration voltages. Our findings indicate that the degradation of g-C3N4 occurs with N species preferentially removed over C species. However, the precise nitrogen group from which N is removed from g-C3N4 (C-N-C, [double bond, length as m-dash]NH or -NH2) is unclear. Moreover, the rate of degradation increases with decreasing electron acceleration voltage, suggesting that inelastic scattering events (radiolysis) dominate over elastic events (knock-on damage). The rate of degradation by removing N atoms is also sensitive to the current density. Hence, we demonstrate that both the electron acceleration voltage and the current density are parameters with which one can use to control the stoichiometry. Moreover, as N species were preferentially removed, the d-spacing of the carbon nitride structure increased. These findings provide a deeper understanding of g-C3N4.
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Affiliation(s)
- Rafael G Mendes
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069 Dresden, Germany.
| | - Huy Q Ta
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069 Dresden, Germany.
| | - Xiaoqin Yang
- School of Energy and Power Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi 710049, China
| | - Alicja Bachmatiuk
- Polish Center for Technology Development (PORT), Ul. Stabłowicka 147, Wrocław 54-066, Poland and Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Skłodowskiej 34, Zabrze 41-819, Poland
| | - Petr Praus
- Department of Chemistry, VŠB-Technical University of Ostrava, Czech Republic and Center for Energy and Environmental Technologies, VŠB-Technical University of Ostrava, 17 Listopadu 15, Ostrava, 708 33, Czech Republic
| | - Aref Mamakhel
- Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Bo B Iversen
- Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Ren Su
- Soochow Institute for Energy and Materials Innovations, College of Energy, Collaborative Innovation Center of Suzhou Nano Science and Technology, Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou 215006, China.
| | - Thomas Gemming
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069 Dresden, Germany.
| | - Mark H Rümmeli
- Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069 Dresden, Germany. and Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Skłodowskiej 34, Zabrze 41-819, Poland and Center for Energy and Environmental Technologies, VŠB-Technical University of Ostrava, 17 Listopadu 15, Ostrava, 708 33, Czech Republic and Soochow Institute for Energy and Materials Innovations, College of Energy, Collaborative Innovation Center of Suzhou Nano Science and Technology, Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou 215006, China.
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Naydenova K, McMullan G, Peet MJ, Lee Y, Edwards PC, Chen S, Leahy E, Scotcher S, Henderson R, Russo CJ. CryoEM at 100 keV: a demonstration and prospects. IUCRJ 2019; 6:1086-1098. [PMID: 31709064 PMCID: PMC6830209 DOI: 10.1107/s2052252519012612] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 09/10/2019] [Indexed: 05/23/2023]
Abstract
100 kV is investigated as the operating voltage for single-particle electron cryomicroscopy (cryoEM). Reducing the electron energy from the current standard of 300 or 200 keV offers both cost savings and potentially improved imaging. The latter follows from recent measurements of radiation damage to biological specimens by high-energy electrons, which show that at lower energies there is an increased amount of information available per unit damage. For frozen hydrated specimens around 300 Å in thickness, the predicted optimal electron energy for imaging is 100 keV. Currently available electron cryomicroscopes in the 100-120 keV range are not optimized for cryoEM as they lack both the spatially coherent illumination needed for the high defocus used in cryoEM and imaging detectors optimized for 100 keV electrons. To demonstrate the potential of imaging at 100 kV, the voltage of a standard, commercial 200 kV field-emission gun (FEG) microscope was reduced to 100 kV and a side-entry cryoholder was used. As high-efficiency, large-area cameras are not currently available for 100 keV electrons, a commercial hybrid pixel camera designed for X-ray detection was attached to the camera chamber and was used for low-dose data collection. Using this configuration, five single-particle specimens were imaged: hepatitis B virus capsid, bacterial 70S ribosome, catalase, DNA protection during starvation protein and haemoglobin, ranging in size from 4.5 MDa to 64 kDa with corresponding diameters from 320 to 72 Å. These five data sets were used to reconstruct 3D structures with resolutions between 8.4 and 3.4 Å. Based on this work, the practical advantages and current technological limitations to single-particle cryoEM at 100 keV are considered. These results are also discussed in the context of future microscope development towards the goal of rapid, simple and widely available structure determination of any purified biological specimen.
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Affiliation(s)
- K. Naydenova
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - G. McMullan
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - M. J. Peet
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - Y. Lee
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - P. C. Edwards
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - S. Chen
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - E. Leahy
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - S. Scotcher
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - R. Henderson
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
| | - C. J. Russo
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England
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Hugenschmidt M, Müller E, Gerthsen D. Electron beam broadening in electron-transparent samples at low electron energies. J Microsc 2019; 274:150-157. [PMID: 31001840 DOI: 10.1111/jmi.12793] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 11/30/2022]
Abstract
Scanning transmission electron microscopy (STEM) at low primary electron energies has received increasing attention in recent years because knock-on damage can be avoided and high contrast for weakly scattering materials is obtained. However, the broadening of the electron beam in the sample is pronounced at low electron energies, which degrades resolution and limits the maximum specimen thickness. In this work, we have studied electron beam broadening in materials with atomic numbers Z between 10 and 32 (MgO, Si, SrTiO3 , Ge) and thicknesses up to 900 nm. Beam broadening is directly measured using a multisegmented STEM detector installed in a scanning electron microscope at electron energies between 15 and 30 keV. For experimental reasons, the electron beam diameter is defined to contain only 68% of the total intensity instead of the commonly used 90% of the total beam intensity. The measured beam diameters can be well described with calculated ones based on a recently published model by Gauvin and Rudinsky. Using the concept of anomalous diffusion the Hurst exponent H is introduced that varies between 0.5 and 1 for different scattering regimes depending on t/Λel with the specimen thickness t and the elastic mean free path length Λel . The calculations also depend on the fraction of the beam intensity that defines the electron beam diameter. A Hurst exponent H of 1 is characteristic for the ballistic scattering regime with t/Λel → 0 and can be excluded for the experimental conditions of our study with 6 ≦ t/Λel ≦ 30. We deduced H = 0.75 from measured beam diameters which is larger than H = 0.5 that is expected under diffusion conditions. The deviation towards larger H values can be rationalised by our definition of electron diameter that contains only 68% of the total beam intensity and requires therefore larger sample thicknesses before the diffusion regime is reached. Our results clearly deviate from previous analytical approaches to describe beam broadening (Goldstein et al., Reed, Williams et al., Kohl and Reimer). Measured beam diameters are compared with simulated ones, which are obtained by solving the electron transport equation. This approach is advantageous compared to the commonly used Monte Carlo simulations because it is an exact solution of the electron transport equation and requires less computer time. Simulated beam diameter agree well with the experimental data and yield H = 0.80. LAY DESCRIPTION: In scanning transmission electron microscopy (STEM), a focused electron beam is scanned over an electron-transparent sample and an image is formed by detecting the intensity of the transmitted electrons by a STEM detector. STEM resolution is ultimately limited by the electron beam diameter and can be better than 0.1 nm for the best microscopes. However, the electron-beam diameter increases with increasing specimen thickness because electrons are scattered by the interaction of the specimen material and electrons. Electron scattering leads to a change of the electron propagation direction and reduces focusing of the electron beam. The associated electron-beam broadening degrades the lateral resolution of STEM and generally limits the maximum specimen thickness that can be imaged with good resolution. STEM is up to now mainly performed at high electron energies of 80 keV and above. Lower electron energies are beneficial for the study of weakly scattering and radiation-sensitive materials but electron beam broadening becomes more pronounced with decreasing electron energies. Knowledge of beam broadening is therefore particularly important for the interpretation of STEM images that are taken with low-energy electrons. In this work we have studied electron-beam broadening in different materials with thicknesses up to 900 nm at low electron energies between 15 and 30 keV. Beam broadening is directly measured with a newly developed technique. We compare measured beam diameters with different models on beam broadening from literature and find that only a recently published model is well suited to describe the experimental results under our experimental conditions. In addition, beam broadening is simulated by modelling electron propagation in the specimen. The simulation results agree well with the measured beam diameters.
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Affiliation(s)
- M Hugenschmidt
- Laboratory for Electron Microscopy (LEM), Karlsruhe Institute of Technology (KIT), Engesserstr. 7, 76131, Karlsruhe, Baden-Württemberg, Germany
| | - E Müller
- Laboratory for Electron Microscopy (LEM), Karlsruhe Institute of Technology (KIT), Engesserstr. 7, 76131, Karlsruhe, Baden-Württemberg, Germany
| | - D Gerthsen
- Laboratory for Electron Microscopy (LEM), Karlsruhe Institute of Technology (KIT), Engesserstr. 7, 76131, Karlsruhe, Baden-Württemberg, Germany
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7
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Brodusch N, Demers H, Gellé A, Moores A, Gauvin R. Electron energy-loss spectroscopy (EELS) with a cold-field emission scanning electron microscope at low accelerating voltage in transmission mode. Ultramicroscopy 2018; 203:21-36. [PMID: 30595397 DOI: 10.1016/j.ultramic.2018.12.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/18/2018] [Accepted: 12/23/2018] [Indexed: 11/29/2022]
Abstract
A commercial electron energy-loss spectrometer (EELS) attached to a high-resolution cold-field emission scanning electron microscope in transmission mode (STEM) is evaluated and its potential for characterizing materials science thin specimens at low accelerating voltage is reviewed. Despite the increased beam radiation damage at SEM voltages on sensitive compounds, we describe some potential applications which benefit from lowering the primary electrons voltage on less-sensitive specimens. We report bandgap measurements on several dielectrics which were facilitated by the lack of Cherenkov radiation losses at 30 kV. The possibility of volume plasmon imaging to probe local composition changes in complex materials was demonstrated using energy-filtered STEM, either via spectrum imaging or elemental mapping using the "three-windows" method. As plasmonic materials are increasing used for energy, electronics or biomedical applications, the ability of reliably evaluate their properties at low accelerating voltage in a SEM is very appealing and is demonstrated. The energy resolution of the spectrometer, taken as the full width at half maximum of the zero-loss peak, was routinely measured at around 0.55 eV and it is demonstrated that t/λ ratios up to 1.5 allowed practical EEL spectroscopy at 30 kV.
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Affiliation(s)
- Nicolas Brodusch
- Department of Mining and Materials Engineering, McGill University, Montréal, Québec H3A 0C5, Canada.
| | - Hendrix Demers
- Department of Mining and Materials Engineering, McGill University, Montréal, Québec H3A 0C5, Canada
| | - Alexandra Gellé
- Department of Chemistry, McGill University, Montréal, Québec H3A 0C5, Canada
| | - Audrey Moores
- Department of Chemistry, McGill University, Montréal, Québec H3A 0C5, Canada
| | - Raynald Gauvin
- Department of Mining and Materials Engineering, McGill University, Montréal, Québec H3A 0C5, Canada.
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Active Sites in Heterogeneous Catalytic Reaction on Metal and Metal Oxide: Theory and Practice. Catalysts 2018. [DOI: 10.3390/catal8100478] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Active sites play an essential role in heterogeneous catalysis and largely determine the reaction properties. Yet identification and study of the active sites remain challenging owing to their dynamic behaviors during catalysis process and issues with current characterization techniques. This article provides a short review of research progresses in active sites of metal and metal oxide catalysts, which covers the past achievements, current research status, and perspectives in this research field. In particular, the concepts and theories of active sites are introduced. Major experimental and computational approaches that are used in active site study are summarized, with their applications and limitations being discussed. An outlook of future research direction in both experimental and computational catalysis research is provided.
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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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Drees H, Müller E, Dries M, Gerthsen D. Electron-beam broadening in amorphous carbon films in low-energy scanning transmission electron microscopy. Ultramicroscopy 2018; 185:65-71. [DOI: 10.1016/j.ultramic.2017.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 10/30/2017] [Accepted: 11/13/2017] [Indexed: 11/24/2022]
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11
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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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12
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Majorovits E, Angert I, Kaiser U, Schröder RR. Benefits and Limitations of Low-kV Macromolecular Imaging of Frozen-Hydrated Biological Samples. Biophys J 2016; 110:776-84. [PMID: 26910420 DOI: 10.1016/j.bpj.2016.01.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 01/18/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022] Open
Abstract
Object contrast is one of the most important parameters of macromolecular imaging. Low-voltage transmission electron microscopy has shown an increased atom contrast for carbon materials, indicating that amplitude contrast contributions increase at a higher rate than phase contrast and inelastic scattering. Here, we studied image contrast using ice-embedded tobacco mosaic virus particles as test samples at 20-80 keV electron energy. The particles showed the expected increase in contrast for lower energies, but at the same time the 2.3-nm-resolution measure decayed more rapidly. We found a pronounced signal loss below 60 keV, and therefore we conclude that increased inelastic scattering counteracts increased amplitude contrast. This model also implies that as long as the amplitude contrast does not increase with resolution, beam damage and multiple scattering will always win over increased contrast at the lowest energies. Therefore, we cannot expect that low-energy imaging of conventionally prepared samples would provide better data than state-of-the-art 200-300 keV imaging.
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Affiliation(s)
| | | | | | - Rasmus R Schröder
- Centre for Advanced Materials, Universität Heidelberg, Heidelberg, Germany; Cryo Electron Microscopy, CellNetworks, BioQuant, Universitätsklinikum Heidelberg, Heidelberg, Germany.
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Liao Z, Gall M, Yeap KB, Sander C, Clausner A, Mühle U, Gluch J, Standke Y, Aubel O, Beyer A, Hauschildt M, Zschech E. In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices. J Vis Exp 2015:e52447. [PMID: 26167933 DOI: 10.3791/52447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. The aggressive scaling of feature sizes, both on devices and interconnects, leads to serious challenges to ensure the required product reliability. Standard reliability tests and post-mortem failure analysis provide only limited information about the physics of failure mechanisms and degradation kinetics. Therefore it is necessary to develop new experimental approaches and procedures to study the TDDB failure mechanisms and degradation kinetics in particular. In this paper, an in situ experimental methodology in the transmission electron microscope (TEM) is demonstrated to investigate the TDDB degradation and failure mechanisms in Cu/ULK interconnect stacks. High quality imaging and chemical analysis are used to study the kinetic process. The in situ electrical test is integrated into the TEM to provide an elevated electrical field to the dielectrics. Electron tomography is utilized to characterize the directed Cu diffusion in the insulating dielectrics. This experimental procedure opens a possibility to study the failure mechanism in interconnect stacks of microelectronic products, and it could also be extended to other structures in active devices.
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Affiliation(s)
- Zhongquan Liao
- Fraunhofer Institute for Ceramic Technologies and Systems; Dresden Center for Nanoanalysis, Technische Universität Dresden
| | - Martin Gall
- Fraunhofer Institute for Ceramic Technologies and Systems;
| | - Kong Boon Yeap
- Fraunhofer Institute for Ceramic Technologies and Systems; Globalfoundries Fab 8
| | | | - André Clausner
- Fraunhofer Institute for Ceramic Technologies and Systems
| | - Uwe Mühle
- Fraunhofer Institute for Ceramic Technologies and Systems
| | - Jürgen Gluch
- Fraunhofer Institute for Ceramic Technologies and Systems
| | - Yvonne Standke
- Fraunhofer Institute for Ceramic Technologies and Systems
| | | | | | | | - Ehrenfried Zschech
- Fraunhofer Institute for Ceramic Technologies and Systems; Dresden Center for Nanoanalysis, Technische Universität Dresden
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14
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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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15
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Su DS, Zhang B, Schlögl R. Electron microscopy of solid catalysts--transforming from a challenge to a toolbox. Chem Rev 2015; 115:2818-82. [PMID: 25826447 DOI: 10.1021/cr500084c] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Dang Sheng Su
- †Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.,‡Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Bingsen Zhang
- †Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China
| | - Robert Schlögl
- ‡Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
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16
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Bachmatiuk A, Zhao J, Gorantla SM, Martinez IGG, Wiedermann J, Lee C, Eckert J, Rummeli MH. Low voltage transmission electron microscopy of graphene. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:515-42. [PMID: 25408379 DOI: 10.1002/smll.201401804] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/27/2014] [Indexed: 05/27/2023]
Abstract
The initial isolation of graphene in 2004 spawned massive interest in this two-dimensional pure sp(2) carbon structure due to its incredible electrical, optical, mechanical, and thermal effects. This in turn led to the rapid development of various characterization tools for graphene. Examples include Raman spectroscopy and scanning tunneling microscopy. However, the one tool with the greatest prowess for characterizing and studying graphene is the transmission electron microscope. State-of-the-art (scanning) transmission electron microscopes enable one to image graphene with atomic resolution, and also to conduct various other characterizations simultaneously. The advent of aberration correctors was timely in that it allowed transmission electron microscopes to operate with reduced acceleration voltages, so that damage to graphene is avoided while still providing atomic resolution. In this comprehensive review, a brief introduction is provided to the technical aspects of transmission electron microscopes relevant to graphene. The reader is then introduced to different specimen preparation techniques for graphene. The different characterization approaches in both transmission electron microscopy and scanning transmission electron microscopy are then discussed, along with the different aspects of electron diffraction and electron energy loss spectroscopy. The use of graphene for other electron microscopy approaches such as in-situ investigations is also presented.
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Affiliation(s)
- Alicja Bachmatiuk
- IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Daejon, 305-701, Republic of Korea; IFW Dresden, Institute of Complex Materials, P.O. Box 270116, D-01171, Dresden, Germany; Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Sklodowskiej 34, Zabrze, 41-819, Poland
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17
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Sasaki T, Sawada H, Hosokawa F, Sato Y, Suenaga K. Aberration-corrected STEM/TEM imaging at 15 kV. Ultramicroscopy 2014; 145:50-5. [DOI: 10.1016/j.ultramic.2014.04.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 04/01/2014] [Accepted: 04/14/2014] [Indexed: 11/17/2022]
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18
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Bell DC, Mankin M, Day RW, Erdman N. Successful application of Low Voltage Electron Microscopy to practical materials problems. Ultramicroscopy 2014; 145:56-65. [DOI: 10.1016/j.ultramic.2014.03.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 02/25/2014] [Accepted: 03/08/2014] [Indexed: 11/17/2022]
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19
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Egerton R. Choice of operating voltage for a transmission electron microscope. Ultramicroscopy 2014; 145:85-93. [DOI: 10.1016/j.ultramic.2013.10.019] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 10/14/2013] [Accepted: 10/24/2013] [Indexed: 10/25/2022]
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20
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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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21
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Lichte H, Börrnert F, Lenk A, Lubk A, Röder F, Sickmann J, Sturm S, Vogel K, Wolf D. Electron holography for fields in solids: problems and progress. Ultramicroscopy 2013; 134:126-34. [PMID: 23831133 DOI: 10.1016/j.ultramic.2013.05.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/13/2013] [Accepted: 05/14/2013] [Indexed: 11/18/2022]
Abstract
Electron holography initially was invented by Dennis Gabor for solving the problems raised by the aberrations of electron lenses in Transmission Electron Microscopy. Nowadays, after hardware correction of aberrations allows true atomic resolution of the structure, for comprehensive understanding of solids, determination of electric and magnetic nanofields is the most challenging task. Since fields are phase objects in the TEM, electron holography is the unrivaled method of choice. After more than 40 years of experimental realization and steady improvement, holography is increasingly contributing to these highly sophisticated and essential questions in materials science, as well to the understanding of electron waves and their interaction with matter.
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Affiliation(s)
- Hannes Lichte
- Triebenberg Laboratory, Institute of Structure Physics, Technische Universität Dresden, Zum Triebenberg 50, 01328 Dresden, Germany.
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22
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Schramm SM, van der Molen SJ, Tromp RM. Intrinsic instability of aberration-corrected electron microscopes. PHYSICAL REVIEW LETTERS 2012; 109:163901. [PMID: 23215077 DOI: 10.1103/physrevlett.109.163901] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Indexed: 06/01/2023]
Abstract
Aberration-corrected microscopes with subatomic resolution will impact broad areas of science and technology. However, the experimentally observed lifetime of the corrected state is just a few minutes. Here we show that the corrected state is intrinsically unstable; the higher its quality, the more unstable it is. Analyzing the contrast transfer function near optimum correction, we define an "instability budget" which allows a rational trade-off between resolution and stability. Unless control systems are developed to overcome these challenges, intrinsic instability poses a fundamental limit to the resolution practically achievable in the electron microscope.
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Affiliation(s)
- S M Schramm
- Leiden University, Kamerlingh Onnes Laboratorium, P.O. Box 9504, NL-2300 RA Leiden, The Netherlands
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23
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Egerton RF. Mechanisms of radiation damage in beam-sensitive specimens, for TEM accelerating voltages between 10 and 300 kV. Microsc Res Tech 2012; 75:1550-6. [PMID: 22807142 DOI: 10.1002/jemt.22099] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 06/20/2012] [Indexed: 11/07/2022]
Abstract
Ionization damage (radiolysis) and knock-on displacement are compared in terms of scattering cross section and stopping power, for thin organic specimens exposed to the electrons in a TEM. Based on stopping power, which includes secondary processes, radiolysis is found to be predominant for all incident energies (10-300 keV), even in materials containing hydrogen. For conducting inorganic specimens, knock-on displacement is the only damage mechanism but an electron dose exceeding 1000 C cm(-2) is usually required. Ways of experimentally determining the damage mechanism (with a view to minimizing damage) are discussed.
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Affiliation(s)
- R F Egerton
- Physics Department, University of Alberta, Edmonton, Canada.
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