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Bauer S, Nergis B, Jin X, Schneider R, Wang D, Kübel C, Machovec P, Horak L, Holy V, Seemann K, Baumbach T, Ulrich S. Dependence of the Structural and Magnetic Properties on the Growth Sequence in Heterostructures Designed by YbFeO 3 and BaFe 12O 19. Nanomaterials (Basel) 2024; 14:711. [PMID: 38668205 PMCID: PMC11054277 DOI: 10.3390/nano14080711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/12/2024] [Accepted: 04/13/2024] [Indexed: 04/29/2024]
Abstract
The structure and the chemical composition of individual layers as well as of interfaces belonging to the two heterostructures M1 (BaFe12O19/YbFeO3/YSZ) and M2 (YbFeO3/BaFe12O19/YSZ) grown by pulsed laser deposition on yttria-stabilized zirconia (YSZ) substrates are deeply characterized by using a combination of methods such as high-resolution X-ray diffraction, transmission electron microscopy (TEM), and atomic-resolution scanning TEM with energy-dispersive X-ray spectroscopy. The temperature-dependent magnetic properties demonstrate two distinct heterostructures with different coercivity, anisotropy fields, and first anisotropy constants, which are related to the defect concentrations within the individual layers and to the degree of intermixing at the interface. The heterostructure with the stacking order BaFe12O19/YbFeO3, i.e., M1, exhibits a distinctive interface without any chemical intermixture, while an Fe-rich crystalline phase is observed in M2 both in atomic-resolution EDX maps and in mass density profiles. Additionally, M1 shows high c-axis orientation, which induces a higher anisotropy constant K1 as well as a larger coercivity due to a high number of phase boundaries. Despite the existence of a canted antiferromagnetic/ferromagnetic combination (T < 140 K), both heterostructures M1 and M2 do not reveal any detectable exchange bias at T = 50 K. Additionally, compressive residual strain on the BaM layer is found to be suppressing the ferromagnetism, thus reducing the Curie temperature (Tc) in the case of M1. These findings suggest that M1 (BaFe12O19/YbFeO3/YSZ) is suitable for magnetic storage applications.
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Affiliation(s)
- Sondes Bauer
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (B.N.); (T.B.)
| | - Berkin Nergis
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (B.N.); (T.B.)
| | - Xiaowei Jin
- Laboratory for Electron Microscopy, Karlsruhe Institute of Technology, Engesserstr. 7, D-76131 Karlsruhe, Germany; (X.J.); (R.S.)
| | - Reinhard Schneider
- Laboratory for Electron Microscopy, Karlsruhe Institute of Technology, Engesserstr. 7, D-76131 Karlsruhe, Germany; (X.J.); (R.S.)
| | - Di Wang
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (D.W.); (C.K.)
- Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Christian Kübel
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (D.W.); (C.K.)
- Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Petr Machovec
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic; (P.M.); (L.H.); (V.H.)
| | - Lukas Horak
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic; (P.M.); (L.H.); (V.H.)
| | - Vaclav Holy
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic; (P.M.); (L.H.); (V.H.)
| | - Klaus Seemann
- Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (K.S.); (S.U.)
| | - Tilo Baumbach
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (B.N.); (T.B.)
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Kaiserstr. 12, D-76131 Karlsruhe, Germany
| | - Sven Ulrich
- Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany; (K.S.); (S.U.)
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Mücke D, Cooley I, Liang B, Wang Z, Park S, Dong R, Feng X, Qi H, Besley E, Kaiser U. Understanding the Electron Beam Resilience of Two-Dimensional Conjugated Metal-Organic Frameworks. Nano Lett 2024; 24:3014-3020. [PMID: 38427697 PMCID: PMC10941249 DOI: 10.1021/acs.nanolett.3c04125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/03/2024]
Abstract
Knowledge of the atomic structure of layer-stacked two-dimensional conjugated metal-organic frameworks (2D c-MOFs) is an essential prerequisite for establishing their structure-property correlation. For this, atomic resolution imaging is often the method of choice. In this paper, we gain a better understanding of the main properties contributing to the electron beam resilience and the achievable resolution in the high-resolution TEM images of 2D c-MOFs, which include chemical composition, density, and conductivity of the c-MOF structures. As a result, sub-angstrom resolution of 0.95 Å has been achieved for the most stable 2D c-MOF of the considered structures, Cu3(BHT) (BHT = benzenehexathiol), at an accelerating voltage of 80 kV in a spherical and chromatic aberration-corrected TEM. Complex damage mechanisms induced in Cu3(BHT) by the elastic interactions with the e-beam have been explained using detailed ab initio molecular dynamics calculations. Experimental and calculated knock-on damage thresholds are in good agreement.
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Affiliation(s)
- David Mücke
- Central
Facility for Materials Science Electron Microscopy, Universität Ulm, 89081 Ulm, Germany
| | - Isabel Cooley
- School
of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Baokun Liang
- Central
Facility for Materials Science Electron Microscopy, Universität Ulm, 89081 Ulm, Germany
| | - Zhiyong Wang
- Max
Planck Institute of Microstructure Physics, 06120 Halle (Saale), Germany
- Faculty
of Chemistry and Food Chemistry & Center for Advancing Electronics
Dresden, Technische Universität Dresden, 01062 Dresden, Germany
| | - SangWook Park
- Faculty
of Chemistry and Food Chemistry & Center for Advancing Electronics
Dresden, Technische Universität Dresden, 01062 Dresden, Germany
| | - Renhao Dong
- Faculty
of Chemistry and Food Chemistry & Center for Advancing Electronics
Dresden, Technische Universität Dresden, 01062 Dresden, Germany
- Key
Laboratory of Colloid and Interface Chemistry of the Ministry of Education,
School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, China
| | - Xinliang Feng
- Max
Planck Institute of Microstructure Physics, 06120 Halle (Saale), Germany
- Faculty
of Chemistry and Food Chemistry & Center for Advancing Electronics
Dresden, Technische Universität Dresden, 01062 Dresden, Germany
| | - Haoyuan Qi
- Central
Facility for Materials Science Electron Microscopy, Universität Ulm, 89081 Ulm, Germany
- Faculty
of Chemistry and Food Chemistry & Center for Advancing Electronics
Dresden, Technische Universität Dresden, 01062 Dresden, Germany
| | - Elena Besley
- School
of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Ute Kaiser
- Central
Facility for Materials Science Electron Microscopy, Universität Ulm, 89081 Ulm, Germany
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Ma Y, Chen Y, Guo T, Wu HH, Wang R, He Y, Wang L, Qiao L. Unraveling the Atomic Shuffles of Twinning Nucleation in Hexagonal Close-Packed Rhenium Nanocrystals. Nano Lett 2023; 23:8498-8504. [PMID: 37695649 DOI: 10.1021/acs.nanolett.3c02100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Reining in deformation twinning is crucial for the mechanical properties of hexagonal close-packed (HCP) metals and hinges on an explicit understanding of the twinning nucleation mechanism. Unfortunately, it is often suggested rather than conclusively demonstrated that twinning nucleation can be mediated by pure atomic shuffles. Herein, by utilizing in situ high-resolution transmission electron microscopy, we have dissected the atomic shuffling mechanism during the {101̅2} twinning nucleation in rhenium nanocrystals, which revealed the emergence of an intermediate body-centered tetragonal (BCT) structure. Specifically, the double-layered prismatic planes initially shuffle into single-layered {11̅0}BCT planes; subsequently, adjacent {22̅0}BCT planes shuffle in opposite directions to form the basal planes of the twin embryo. This shuffling mechanism is further corroborated by molecular dynamic simulations. The finding provides direct evidence of shuffle-dominated twinning nucleation with atomic details that may lead to better control of this critical twinning mode in HCP metals.
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Affiliation(s)
- Yuan Ma
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Yongqing Chen
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Tao Guo
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Hong-Hui Wu
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
- Institute of Materials Intelligent Technology, Liaoning Academy of Materials, Shenyang 110004, People's Republic of China
| | - Rongming Wang
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Yang He
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Luning Wang
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Lijie Qiao
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
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Podlesnaia E, Gerald Inangha P, Vesenka J, Seyring M, Hempel HJ, Rettenmayr M, Csáki A, Fritzsche W. Microfluidic-Generated Seeds for Gold Nanotriangle Synthesis in Three or Two Steps. Small 2023; 19:e2204810. [PMID: 36855325 DOI: 10.1002/smll.202204810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 01/23/2023] [Indexed: 06/02/2023]
Abstract
Nanoparticle synthesis has drawn great attention in the last decades. The study of crystal growth mechanisms and optimization of the existing methods lead to the increasing accessibility of nanomaterials, such as gold nanotriangles which have great potential in the fields of plasmonics and catalysis. To form such structures, a careful balance of reaction parameters has to be maintained. Herein, a novel synthesis of gold nanotriangles from seeds derived with a micromixer, which provides a highly efficient mixing and simple parameter control is reported. The impact of the implemented reactor on the primary seed characteristics is investigated. The following growth steps are studied to reveal the phenomena affecting the shape yield. The use of microfluidic seeds led to the formation of well-defined triangles with a narrower size distribution compared to the entirely conventional batch synthesis. A shortened two-step procedure for the formation of triangles directly from primary seeds, granting an express but robust synthesis is further described. Moreover, the need for a thorough study of seed crystallinity depending on the synthesis conditions, which - together with additional parameter optimization - will bring a new perspective to the use of micromixers which are promising for scaling up nanomaterial production is highlighted.
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Affiliation(s)
- Ekaterina Podlesnaia
- Department of Nanobiophotonics, Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, 07745, Jena, Germany
| | - Princess Gerald Inangha
- Department of Nanobiophotonics, Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, 07745, Jena, Germany
| | - James Vesenka
- Department of Nanobiophotonics, Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, 07745, Jena, Germany
- School of Mathematical and Physical Sciences, University of New England, 11 Hills Beach Road, Biddeford, ME, 04005, USA
| | - Martin Seyring
- Department of Metallic Materials, Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University (FSU), Löbdergraben 32, 07743, Jena, Germany
- Faculty of Electrical Engineering, Schmalkalden University of Applied Sciences, Blechhammer 4-9, 98574, Schmalkalden, Germany
| | - Hans-Jürgen Hempel
- Department of Metallic Materials, Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University (FSU), Löbdergraben 32, 07743, Jena, Germany
| | - Markus Rettenmayr
- Department of Metallic Materials, Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University (FSU), Löbdergraben 32, 07743, Jena, Germany
| | - Andrea Csáki
- Department of Nanobiophotonics, Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, 07745, Jena, Germany
| | - Wolfgang Fritzsche
- Department of Nanobiophotonics, Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, 07745, Jena, Germany
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Paredes G, Wang R, Puech P, Seine G, Leyssale JM, Arenal R, Masseboeuf A, Piazza F, Monthioux M. Texture, Nanotexture, and Structure of Carbon Nanotube-Supported Carbon Cones. ACS Nano 2022; 16:9287-9296. [PMID: 35695474 DOI: 10.1021/acsnano.2c01825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Graphene-based carbon micro-/nano-cones were prepared by depositing pyrolytic carbon onto individual carbon nanotubes as supports using a specific chemical vapor deposition process. They were investigated by means of high-resolution scanning electron microscopy, low-voltage aberration-corrected transmission electron microscopy, Raman spectroscopy, and molecular dynamics modeling. While the graphenes were confirmed to be perfect, the cone texture was determined to be preferably scroll-like, with the scroll turns being parallel to the cone axis. Correspondingly, many of the concentrically displayed graphenes (actually scroll turns) exhibit the same helicity vector. When radii of curvature are large enough, this could allow for coherent stacking to locally take place in spite of the lattice shift induced by the curvature. A particular care was taken on investigating the cone apexes, in which a specific type of graphene termination was observed, here designated as the "zip" defect. Calculations determined a plausible stable structure that such a defect type may correspond to. This defect was found to generate a very low Raman ID/ID' band ratio (1.5), for which physical reasons are proposed. Combining our results and that of the literature allowed proposing an identification chart for a variety of defects able to affect the graphene lattice or edges.
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Affiliation(s)
- Germercy Paredes
- Centre d'Elaboration des Matériaux et d'Etudes Structurales (CEMES), UPR8011 CNRS, Université Toulouse III, 31055 Toulouse, France
- Laboratorio de Nanociencia, Pontificia Universidad Católica Madre y Maestra, Santiago de Los Caballeros 51000, Dominican Republic
| | - Rongrong Wang
- Centre d'Elaboration des Matériaux et d'Etudes Structurales (CEMES), UPR8011 CNRS, Université Toulouse III, 31055 Toulouse, France
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
| | - Pascal Puech
- Centre d'Elaboration des Matériaux et d'Etudes Structurales (CEMES), UPR8011 CNRS, Université Toulouse III, 31055 Toulouse, France
| | - Grégory Seine
- Centre d'Elaboration des Matériaux et d'Etudes Structurales (CEMES), UPR8011 CNRS, Université Toulouse III, 31055 Toulouse, France
| | - Jean-Marc Leyssale
- Université deBordeaux, CNRS, Bordeaux INP, Institut des Sciences Moléculaires (ISM), UMR 5255, F-33400 Talence, France
| | - Raul Arenal
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Fundación ARAID, 50018 Zaragoza, Spain
- Instituto de Nanociencia y Materiales de Aragon (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Aurélien Masseboeuf
- Centre d'Elaboration des Matériaux et d'Etudes Structurales (CEMES), UPR8011 CNRS, Université Toulouse III, 31055 Toulouse, France
| | - Fabrice Piazza
- Laboratorio de Nanociencia, Pontificia Universidad Católica Madre y Maestra, Santiago de Los Caballeros 51000, Dominican Republic
| | - Marc Monthioux
- Centre d'Elaboration des Matériaux et d'Etudes Structurales (CEMES), UPR8011 CNRS, Université Toulouse III, 31055 Toulouse, France
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Zhang X, Zhang X, Ajayan PM, Wen J, Espinosa HD. Edge-Mediated Annihilation of Vacancy Clusters in Monolayer Molybdenum Diselenide (MoSe 2 ) under Electron Beam Irradiation. Small 2022; 18:e2105194. [PMID: 34783451 DOI: 10.1002/smll.202105194] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Annihilation of vacancy clusters in monolayer molybdenum diselenide (MoSe2 ) under electron beam irradiation is reported. In situ high-resolution transmission electron microscopy observation reveals that the annihilation is achieved by diffusion of vacancies to the free edge near the vacancy clusters. Monte Carlo simulations confirm that it is energetically favorable for the vacancies to locate at the free edge. By computing the minimum energy path for the annihilation of one vacancy cluster as a case study, it is further shown that electron beam irradiation and pre-stress in the suspended MoSe2 monolayer are necessary for the vacancies to overcome the energy barriers for diffusion. The findings suggest a new mechanism of vacancy healing in 2D materials and broaden the capability of electron beam for defect engineering of 2D materials, a promising way of tuning their properties for engineering applications.
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Affiliation(s)
- Xu Zhang
- Theoretical and Applied Mechanics Program, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208, USA
| | - Xiang Zhang
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, TX, 77005, USA
| | - Pulickel M Ajayan
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, TX, 77005, USA
| | - Jianguo Wen
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Horacio D Espinosa
- Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208, USA
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7
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Vats N, Negi DS, Singh D, Sigle W, Abb S, Sen S, Szilagyi S, Ochner H, Ahuja R, Kern K, Rauschenbach S, van Aken PA. Catalyzing Bond-Dissociation in Graphene via Alkali-Iodide Molecules. Small 2021; 17:e2102037. [PMID: 34528384 DOI: 10.1002/smll.202102037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Atomic design of a 2D-material such as graphene can be substantially influenced by etching, deliberately induced in a transmission electron microscope. It is achieved primarily by overcoming the threshold energy for defect formation by controlling the kinetic energy and current density of the fast electrons. Recent studies have demonstrated that the presence of certain species of atoms can catalyze atomic bond dissociation processes under the electron beam by reducing their threshold energy. Most of the reported catalytic atom species are single atoms, which have strong interaction with single-layer graphene (SLG). Yet, no such behavior has been reported for molecular species. This work shows by experimentally comparing the interaction of alkali and halide species separately and conjointly with SLG, that in the presence of electron irradiation, etching of SLG is drastically enhanced by the simultaneous presence of alkali and iodine atoms. Density functional theory and first principles molecular dynamics calculations reveal that due to charge-transfer phenomena the CC bonds weaken close to the alkali-iodide species, which increases the carbon displacement cross-section. This study ascribes pronounced etching activity observed in SLG to the catalytic behavior of the alkali-iodide species in the presence of electron irradiation.
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Affiliation(s)
- Nilesh Vats
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
| | - Devendra S Negi
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
| | - Deobrat Singh
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, 75120, Sweden
| | - Wilfried Sigle
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
| | - Sabine Abb
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
| | - Suman Sen
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
| | - Sven Szilagyi
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
| | - Hannah Ochner
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
| | - Rajeev Ahuja
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, 75120, Sweden
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab, 140001, India
| | - Klaus Kern
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
- Institut de Physique de la Matière Condensée, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
| | - Stephan Rauschenbach
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
- Department of Chemistry, University of Oxford, 12, Mansfield Road, Oxford, OX1 3TA, UK
| | - Peter A van Aken
- Max Planck Institute for Solid State Research, Heisenberstr.1, 70569, Stuttgart, Germany
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Sadre R, Ophus C, Butko A, Weber GH. Deep Learning Segmentation of Complex Features in Atomic-Resolution Phase-Contrast Transmission Electron Microscopy Images. Microsc Microanal 2021; 27:804-814. [PMID: 34353384 DOI: 10.1017/s1431927621000167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Phase-contrast transmission electron microscopy (TEM) is a powerful tool for imaging the local atomic structure of materials. TEM has been used heavily in studies of defect structures of two-dimensional materials such as monolayer graphene due to its high dose efficiency. However, phase-contrast imaging can produce complex nonlinear contrast, even for weakly scattering samples. It is, therefore, difficult to develop fully automated analysis routines for phase-contrast TEM studies using conventional image processing tools. For automated analysis of large sample regions of graphene, one of the key problems is segmentation between the structure of interest and unwanted structures such as surface contaminant layers. In this study, we compare the performance of a conventional Bragg filtering method with a deep learning routine based on the U-Net architecture. We show that the deep learning method is more general, simpler to apply in practice, and produces more accurate and robust results than the conventional algorithm. We provide easily adaptable source code for all results in this paper and discuss potential applications for deep learning in fully automated TEM image analysis.
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Affiliation(s)
- Robbie Sadre
- Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Colin Ophus
- NCEM, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Anastasiia Butko
- Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Gunther H Weber
- Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
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Plesiutschnig E, Albu M, Canelo-Yubero D, Razumovskiy VI, Stark A, Schell N, Kothleitner G, Beal C, Sommitsch C, Hofer F. An In Situ Synchrotron Dilatometry and Atomistic Study of Martensite and Carbide Formation during Partitioning and Tempering. Materials (Basel) 2021; 14:3849. [PMID: 34300775 DOI: 10.3390/ma14143849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 11/17/2022]
Abstract
Precipitation hardened and tempered martensitic-ferritic steels (TMFSs) are used in many areas of our daily lives as tools, components in power generation industries, or in the oil and gas (O&G) industry for creep and corrosion resistance. In addition to the metallurgical and forging processes, the unique properties of the materials in service are determined by the quality heat treatment (HT). By performing a quenching and partitioning HT during an in situ high energy synchrotron radiation experiment in a dilatometer, the evolution of retained austenite, martensite laths, dislocations, and carbides was characterized in detail. Atomic-scale studies on a specimen with the same HT subjected to a laser scanning confocal microscope show how dislocations facilitate cloud formation around carbides. These clouds have a discrete build-up, and thermodynamic calculations and density functional theory explain their stability.
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10
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Lee JK, Kim JG, Hembram KPSS, Yu S, Lee SG. AB-stacked nanosheet-based hexagonal boron nitride. Acta Crystallogr B Struct Sci Cryst Eng Mater 2021; 77:260-265. [PMID: 33843734 PMCID: PMC8040095 DOI: 10.1107/s2052520621000317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 01/10/2021] [Indexed: 06/12/2023]
Abstract
Hexagonal boron nitride (h-BN) has been generally interpreted as having an AA stacking sequence. Evidence is presented in this article indicating that typical commercial h-BN platelets (∼10-500 nm in thickness) exhibit stacks of parallel nanosheets (∼10 nm in thickness) predominantly in the AB sequence. The AB-stacked nanosheet occurs as a metastable phase of h-BN resulting from the preferred texture and lateral growth of armchair (110) planes. It appears as an independent nanosheet or unit for h-BN platelets. The analysis is supported by simulation of thin AB films (2-20 layers), which explains the unique X-ray diffraction pattern of h-BN. With this analysis and the role of pressure in commercial high-pressure high-temperature sintering (driving nucleation and parallelizing the in-plane crystalline growth of the nuclei), a growth mechanism is proposed for 2D h-BN (on a substrate) as `substrate-induced 2D growth', where the substrate plays the role of pressure.
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Affiliation(s)
- Jae-Kap Lee
- Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Jin-Gyu Kim
- Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon, 34133, Republic of Korea
| | - K. P. S. S. Hembram
- Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Seunggun Yu
- Insulation Materials Research Center, Korea Electrotechnology Research Institute, Changwon, 51543, Republic of Korea
| | - Sang-Gil Lee
- Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon, 34133, Republic of Korea
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11
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Beladi-Mousavi SM, Ying Y, Plutnar J, Pumera M. Bismuthene Metallurgy: Transformation of Bismuth Particles to Ultrahigh-Aspect-Ratio 2D Microsheets. Small 2020; 16:e2002037. [PMID: 32519439 DOI: 10.1002/smll.202002037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 05/07/2020] [Indexed: 06/11/2023]
Abstract
Ultrathin bismuth exhibits promising performance for topological insulators due to its narrow band gap and intrinsic strong spin-orbit coupling, as well as for energy-related applications because of its electronic and mechanical properties. However, large-scale production of 2D sheets via liquid-phase exfoliation as an established large-scale method is restricted by the strong interaction between bismuth layers. Here, a sonication method is utilized to produce ultrahigh-aspect-ratio bismuthene microsheets. The studies on the mechanism excludes the exfoliation of the layered bulk bismuth and formation of the microsheets is attributed to the melting of spherical particles (r = 1.5 µm) at a high temperature-generated under the ultrasonic tip-followed by a recrystallization step producing uniformly-shaped ultrathin microsheets (A = 0.5-2 µm2 , t: ≈2 nm). Notably, although the preparation is performed in oxygenated aqueous solution, the sheets are not oxidized, and they are stable under ambient conditions for at least 1 month. The microsheets are used to construct a vapor sensor using electrochemical impedance spectroscopy as detection technique. The device is highly selective, and it shows long-term stability. Overall, this project exhibits a reproducible method for large-scale preparation of ultrathin bismuthene microsheets in a benign environment, demonstrating opportunities to realize devices based on bismuthene.
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Affiliation(s)
- Seyyed Mohsen Beladi-Mousavi
- Center for the Advanced Functional Nanorobots, Department of Inorganic Chemistry, University of Chemistry and Technology, Technická 5, Prague, Czech Republic
| | - Yulong Ying
- Center for the Advanced Functional Nanorobots, Department of Inorganic Chemistry, University of Chemistry and Technology, Technická 5, Prague, Czech Republic
| | - Jan Plutnar
- Center for the Advanced Functional Nanorobots, Department of Inorganic Chemistry, University of Chemistry and Technology, Technická 5, Prague, Czech Republic
| | - Martin Pumera
- Center for the Advanced Functional Nanorobots, Department of Inorganic Chemistry, University of Chemistry and Technology, Technická 5, Prague, Czech Republic
- Department of Medical Research, China Medical University Hospital, China Medical University, No. 91 Hsueh-Shih Road, Taichung, Taiwan
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
- Future Energy and Innovation Laboratory, Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, Brno, CZ-616 00, Czech Republic
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12
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Kretschmer S, Lehnert T, Kaiser U, Krasheninnikov AV. Formation of Defects in Two-Dimensional MoS 2 in the Transmission Electron Microscope at Electron Energies below the Knock-on Threshold: The Role of Electronic Excitations. Nano Lett 2020; 20:2865-2870. [PMID: 32196349 DOI: 10.1021/acs.nanolett.0c00670] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Production of defects under electron irradiation in a transmission electron microscope (TEM) due to inelastic effects has been reported for various materials, but the microscopic mechanism of damage development in periodic solids through this channel is not fully understood. We employ non-adiabatic Ehrenfest, along with constrained density functional theory molecular dynamics, and simulate defect production in two-dimensional MoS2 under electron beam. We show that when excitations are present in the electronic system, formation of vacancies through ballistic energy transfer is possible at electron energies which are much lower than the knock-on threshold for the ground state. We further carry out TEM experiments on single layers of MoS2 at electron voltages in the range of 20-80 kV and demonstrate that indeed there is an additional channel for defect production. The mechanism involving a combination of the knock-on damage and electronic excitations we propose is relevant to other bulk and nanostructured semiconducting materials.
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Affiliation(s)
- Silvan Kretschmer
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Tibor Lehnert
- Central Facility for Electron Microscopy, Group of Electron Microscopy of Materials Science, Ulm University, Ulm 89081, Germany
| | - Ute Kaiser
- Central Facility for Electron Microscopy, Group of Electron Microscopy of Materials Science, Ulm University, Ulm 89081, Germany
| | - Arkady V Krasheninnikov
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
- Department of Applied Physics, Aalto University, 00076 Aalto, Finland
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13
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Wolff N, Hrkac V, Ditto JJ, Duppel V, Mishra YK, Johnson DC, Adelung R, Kienle L. Crystallography at the nanoscale: planar defects in ZnO nanospikes. J Appl Crystallogr 2019; 52:1009-1015. [PMID: 31636519 PMCID: PMC6782080 DOI: 10.1107/s1600576719009415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/01/2019] [Indexed: 11/10/2022] Open
Abstract
The examination of anisotropic nanostructures, such as wires, platelets or spikes, inside a transmission electron microscope is normally performed only in plan view. However, intrinsic defects such as growth twin interfaces could occasionally be concealed from direct observation for geometric reasons, leading to superposition. This article presents the shadow-focused ion-beam technique to prepare multiple electron-beam-transparent cross-section specimens of ZnO nanospikes, via a procedure which could be readily extended to other anisotropic structures. In contrast with plan-view data of the same nanospikes, here the viewing direction allows the examination of defects without superposition. By this method, the coexistence of two twin configurations inside the wurtzite-type structure is observed, namely and , which were not identified during the plan-view observations owing to superposition of the domains. The defect arrangement could be the result of coalescence twinning of crystalline nuclei formed on the partially molten Zn substrate during the flame-transport synthesis. Three-dimensional defect models of the twin interface structures have been derived and are correlated with the plan-view investigations by simulation.
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Affiliation(s)
- Niklas Wolff
- Synthesis and Real Structure and Institute for Material Science, Kiel University, Kaiserstrasse 2, Kiel 24143, Germany
| | - Viktor Hrkac
- Synthesis and Real Structure and Institute for Material Science, Kiel University, Kaiserstrasse 2, Kiel 24143, Germany
| | - Jeffrey J Ditto
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403, USA
| | - Viola Duppel
- Nanochemistry, Max Planck Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart 70569, Germany
| | - Yogendra K Mishra
- Functional Nanomaterials and Institute for Material Science, Kiel University, Kaiserstrasse 2, Kiel 24143, Germany
| | - David C Johnson
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403, USA
| | - Rainer Adelung
- Functional Nanomaterials and Institute for Material Science, Kiel University, Kaiserstrasse 2, Kiel 24143, Germany
| | - Lorenz Kienle
- Synthesis and Real Structure and Institute for Material Science, Kiel University, Kaiserstrasse 2, Kiel 24143, Germany
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14
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Seo J, Hwang KJ, Baik SI, Lee S, Cho B, Jo E, Choi M, Hahm MG, Kim YJ. Three-Dimensional Atomistic Tomography of W-Based Alloyed Two-Dimensional Transition Metal Dichalcogenides. ACS Appl Mater Interfaces 2018; 10:30640-30648. [PMID: 30117322 DOI: 10.1021/acsami.8b09604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Increased interest in two-dimensional (2D) materials and heterostructures for use as components of electrical devices has led to the use of an atomically mixed phase between semiconducting and metallic transition metal dichalcogenides that exhibited enhanced interfacial characteristics. To understand the lattice structure and properties of 2D materials on the atomic scale, diverse characterization methods such as Raman spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and X-ray photoemission spectroscopy (XPS) have been applied. However, determination of the exact chemical distribution, which is a critical factor for the interfacial layer, was hindered by limitations of these typical methods. In this work, atom-probe tomography (APT) was introduced for the first time to analyze the three-dimensional atomic distribution and composition variation of the atomic-scale multilayered alloy structure W xNb(1- x)Se2. Composition profiles and theoretical calculations for each atom demonstrated the reaction kinetics and stoichiometric inhomogeneity of the W xNb(1- x)Se2 layer. The role of the intermediate layer was investigated by fabrication of a WSe2-based field-effect transistor. Introduction of W xNb(1- x)Se2 between metallic NbSe2 and semiconducting WSe2 layers resulted in improved charge transport with lowering of the contact barrier.
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Affiliation(s)
- Juyeon Seo
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Kyo-Jin Hwang
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Sung-Il Baik
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
- Northwestern University Center for Atom-Probe Tomography (NUCAPT) , Evanston , Illinois 60208 , United States
| | - Suryeon Lee
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Byungjin Cho
- Department of Advanced Materials Engineering , Chungbuk National University , 1 Chungdae-ro , Seowon-gu, Cheongju , Chungbuk 28644 , Republic of Korea
| | - Euihyun Jo
- Department of Physics , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Minseok Choi
- Department of Physics , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Myung Gwan Hahm
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Yoon-Jun Kim
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
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15
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Timofeeva M, Bouravleuv A, Cirlin G, Shtrom I, Soshnikov I, Reig Escalé M, Sergeyev A, Grange R. Polar Second-Harmonic Imaging to Resolve Pure and Mixed Crystal Phases along GaAs Nanowires. Nano Lett 2016; 16:6290-6297. [PMID: 27657488 DOI: 10.1021/acs.nanolett.6b02592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In this work, we report an optical method for characterizing crystal phases along single-semiconductor III-V nanowires based on the measurement of polarization-dependent second-harmonic generation. This powerful imaging method is based on a per-pixel analysis of the second-harmonic-generated signal on the incoming excitation polarization. The dependence of the second-harmonic generation responses on the nonlinear second-order susceptibility tensor allows the distinguishing of areas of pure wurtzite, zinc blende, and mixed and rotational twins crystal structures in individual nanowires. With a far-field nonlinear optical microscope, we recorded the second-harmonic generation in GaAs nanowires and precisely determined their various crystal structures by analyzing the polar response for each pixel of the images. The predicted crystal phases in GaAs nanowire are confirmed with scanning transmission electron and high-resolution transmission electron measurements. The developed method of analyzing the nonlinear polar response of each pixel can be used for an investigation of nanowire crystal structure that is quick, sensitive to structural transitions, nondestructive, and on-the-spot. It can be applied for the crystal phase characterization of nanowires built into optoelectronic devices in which electron microscopy cannot be performed (for example, in lab-on-a-chip devices). Moreover, this method is not limited to GaAs nanowires but can be used for other nonlinear optical nanostructures.
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Affiliation(s)
- Maria Timofeeva
- Optical Nanomaterial Group, Institute for Quantum Electronics, Department of Physics, ETH Zurich , Auguste-Piccard Hof 1, 8093 Zurich, Switzerland
- ITMO University , Kronverkskiy 49, 197101 Saint Petersburg, Russia
| | - Alexei Bouravleuv
- St. Petersburg Academic University , Khlopina 8/3, 194021 Saint Petersburg, Russia
- Ioffe Institute , Politekhnicheskaya 29, 194021 Saint Petersburg, Russia
| | - George Cirlin
- St. Petersburg Academic University , Khlopina 8/3, 194021 Saint Petersburg, Russia
- ITMO University , Kronverkskiy 49, 197101 Saint Petersburg, Russia
- Ioffe Institute , Politekhnicheskaya 29, 194021 Saint Petersburg, Russia
| | - Igor Shtrom
- St. Petersburg Academic University , Khlopina 8/3, 194021 Saint Petersburg, Russia
- Ioffe Institute , Politekhnicheskaya 29, 194021 Saint Petersburg, Russia
| | - Ilya Soshnikov
- St. Petersburg Academic University , Khlopina 8/3, 194021 Saint Petersburg, Russia
- Ioffe Institute , Politekhnicheskaya 29, 194021 Saint Petersburg, Russia
| | - Marc Reig Escalé
- Optical Nanomaterial Group, Institute for Quantum Electronics, Department of Physics, ETH Zurich , Auguste-Piccard Hof 1, 8093 Zurich, Switzerland
| | - Anton Sergeyev
- Optical Nanomaterial Group, Institute for Quantum Electronics, Department of Physics, ETH Zurich , Auguste-Piccard Hof 1, 8093 Zurich, Switzerland
| | - Rachel Grange
- Optical Nanomaterial Group, Institute for Quantum Electronics, Department of Physics, ETH Zurich , Auguste-Piccard Hof 1, 8093 Zurich, Switzerland
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16
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Chang Y, Wang Y, Cui Y, Ge B. Investigation of non-linear imaging in high-resolution transmission electron microscopy. Microscopy (Oxf) 2016; 65:465-472. [PMID: 27587507 DOI: 10.1093/jmicro/dfw032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/14/2016] [Indexed: 11/12/2022] Open
Abstract
Transmission cross-coefficient theory and pseudo-weak-phase object approximation theory were combined to investigate the non-linear imaging in high-resolution transmission electron microscopy (HRTEM). The analytical expressions of linear and non-linear imaging components in diffractogram were obtained and changes of linear and non-linear components over sample thickness were analyzed. Moreover, the linear and non-linear components are found to be an odd and even-function of the defocus and Cs, respectively. Based on this, a method for separating the linear and non-linear contrasts in Cs-corrected (non-zero Cs conditions included) HRTEM images was proposed, and its effectiveness was confirmed by image simulations with AlN as an example.
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Affiliation(s)
- Yunjie Chang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yumei Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yanxiang Cui
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Binghui Ge
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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17
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Klinger M, Jäger A. Crystallographic Tool Box ( CrysTBox): automated tools for transmission electron microscopists and crystallographers. J Appl Crystallogr 2015; 48:2012-2018. [PMID: 26664349 PMCID: PMC4665667 DOI: 10.1107/s1600576715017252] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/15/2015] [Indexed: 11/10/2022] Open
Abstract
Three tools for an automated analysis of electron diffraction pattern and crystallographic visualization are presented. Firstly, diffractGUI determines the zone axis from selected area diffraction, convergent beam diffraction or nanodiffraction patterns and allows for indexing of individual reflections. Secondly, ringGUI identifies crystallographic planes corresponding to the depicted rings in the ring diffraction pattern and can select the sample material from a list of candidates. Both diffractGUI and ringGUI employ methods of computer vision for a fast, robust and accurate analysis. Thirdly, cellViewer is an intuitive visualization tool which is also helpful for crystallographic calculations or educational purposes. diffractGUI and cellViewer can be used together during a transmission electron microscopy session to determine the sample holder tilts required to reach a desired zone axis. All the tools offer a graphical user interface. The toolbox is distributed as a standalone application, so it can be installed on the microscope computer and launched directly from DigitalMicrograph (Gatan Inc.).
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Affiliation(s)
- Miloslav Klinger
- Laboratory of Nanostructures and Nanomaterials, Institute of Physics of the ASCR, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - Aleš Jäger
- Laboratory of Nanostructures and Nanomaterials, Institute of Physics of the ASCR, Na Slovance 2, 182 21 Prague 8, Czech Republic
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18
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Sakaguchi N, Kozuka M, Ichinose H. Laser-assisted sample preparation of silicon for high-resolution transmission electron microscopy. Microscopy (Oxf) 2015; 64:111-9. [PMID: 25556781 DOI: 10.1093/jmicro/dfu114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/04/2014] [Indexed: 11/14/2022] Open
Abstract
A sample-polishing technique was developed to provide a well-defined thin foil of Si with a clean surface down to atomic dimensions. The resulting samples permit high-resolution transmission electron microscope (HRTEM) imaging unobstructed by artifacts originating from a damaged sample. Samples were not polished by dynamic momentum transfer via accelerated ions like in ion milling; instead, valence electron excitation by photon absorption was used. HRTEM inspection showed that the foils prepared by this method were free from extrinsic lattice defects and had smooth surfaces down to atomic dimensions.
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Affiliation(s)
- Norihito Sakaguchi
- Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Munehiro Kozuka
- Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan JEOL Co. Ltd., Akishima, Tokyo 196-8558, Japan
| | - Hideki Ichinose
- Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
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19
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Lee JK, Lee S, Kim JG, Min BK, Kim YI, Lee KI, An KH, John P. Structure of single-wall carbon nanotubes: a graphene helix. Small 2014; 10:3283-3290. [PMID: 24838196 DOI: 10.1002/smll.201400884] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 04/19/2014] [Indexed: 06/03/2023]
Abstract
Evidence is presented in this paper that certain single-wall carbon nanotubes are not seamless tubes, but rather adopt a graphene helix resulting from the spiral growth of a nano-graphene ribbon. The residual traces of the helices are confirmed by high-resolution transmission electron microscopy and atomic force microscopy. The analysis also shows that the tubular graphene material may exhibit a unique armchair structure and the chirality is not a necessary condition for the growth of carbon nanotubes. The description of the structure of the helical carbon nanomaterials is generalized using the plane indices of hexagonal space groups instead of using chiral vectors. It is also proposed that the growth model, via a graphene helix, results in a ubiquitous structure of single-wall carbon nanotubes.
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Affiliation(s)
- Jae-Kap Lee
- Interface Control Research Center, Korea Institute of Science and Technology (KIST), Seoul, 130-650, Korea
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20
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Jo J, Yoo H, Park SI, Park JB, Yoon S, Kim M, Yi GC. High-resolution observation of nucleation and growth behavior of nanomaterials using a graphene template. Adv Mater 2014; 26:2011-5. [PMID: 24478255 DOI: 10.1002/adma.201304720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/07/2013] [Indexed: 05/16/2023]
Abstract
By using graphene as an electron beam-transparent substrate for both nanomaterial growth and transmission electron microscopy (TEM) measurements, we investigate initial growth behavior of nanomaterials. The direct growth and imaging method using graphene facilitate atomic-resolution imaging of nanomaterials at the very early stage of growth. This enables the observation of the transition in crystal structure of ZnO nuclei and the formation of various defects during nanomaterial growth.
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Affiliation(s)
- Janghyun Jo
- Department of Physics and Astronomy, Seoul National University, Seoul, 151-747, Korea; Department of Materials Science and Engineering and and Research Institute of Advanced Materials, Seoul National University, Seoul, 151-744, Korea
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21
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Park JS, Yang JM, Park KJ, Park YC, Yoo JH, Jeong CS, Park J, He Y, Shin K. Transmission electron microscopy study of microstructural properties and dislocation characterization in the GaN film grown on the cone-shaped patterned Al2O3 substrate. Microscopy (Oxf) 2013; 63:15-22. [PMID: 24108788 DOI: 10.1093/jmicro/dft040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Growing a GaN film on a patterned Al2O3 substrate is one of the methods of reducing threading dislocations (TDs), which can significantly deteriorate the performance of GaN-based LEDs. In this study, the microstructural details of the GaN film grown on a cone-shaped patterned Al2O3 substrate were investigated using high-resolution transmission electron microscopy and weak-beam dark-field techniques. Various defects such as misfit dislocations (MDs), recrystallized GaN (R-GaN) islands and nano-voids were observed on the patterned Al2O3 surfaces, i.e. the flat surface (FS), the inclined surface (IS) and the top surface (TS), respectively. Especially, the crystallographic orientation of R-GaN between the GaN film and the inclined Al2O3 substrate was identified as $[\overline 1 2\overline 1 0]_{{\rm GaN}} \hbox{//}[\overline 1 101]_{{\rm R - GaN} \,{\rm on}\,{\rm IS}} \hbox{//}[\overline 1 100]_{ {{\rm Al}} _{\rm 2} {\rm O}_{\rm 3}} $, $(\overline 1 012)_{{\rm GaN}} \hbox{//}(1\overline 1 02)_{{\rm R - Ga}\,{\rm Non}\,{\rm IS}} \hbox{//}(\overline {11} 26)_{ {{\rm Al}} _{\rm 2} {\rm O}_{\rm 3}} $. In addition, a rotation by 9° between $(10\overline 1 1)_{{\rm R - GaN}} $ and $(0002)_{{\rm GaN}} $ and between $(10\overline 1 1)_{{\rm R - GaN}} $ and $(0006)_{ {{\rm Al}} _{\rm 2} {\rm O}_{\rm 3}} $ was found to reduce the lattice mismatch between the GaN film and the Al2O3 substrate. Many TDs in the GaN film were observed on the FS and TS of Al2O3. However, few TDs were observed on the IS. Most of the TDs generated from the FS of Al2O3 were bent to the inclined facet rather than propagating to the GaN surface, resulting in a reduction in the dislocation density. Most of the TDs generated from the TS of Al2O3 were characterized as edge dislocations.
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Affiliation(s)
- Jung Sik Park
- Measurement and Analysis Team, National Nanofab Center, Daejeon 305-806, South Korea
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22
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Agatha S, Simon P. On the Nature of Tintinnid Loricae (Ciliophora: Spirotricha: Tintinnina): a Histochemical, Enzymatic, EDX, and High-resolution TEM Study. ACTA PROTOZOOL 2012; 51:1-19. [PMID: 22988335 PMCID: PMC3442249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Tintinnids (Ciliophora: Spirotricha: Tintinnina) are occasionally the dominant ciliates in the marine plankton. The tintinnid loricae are minute artworks fascinating scientists for more than 230 years, but their chemical composition remained unclear, viz., chitinous or proteinaceous substances were discussed. Since sedimenting loricae contribute to the flux of elements and organic compounds in the oceans, knowledge about their nature is necessary in assessing their ecological role. Previous techniques and new methods, e.g. enzymatic digestion and high-resolution transmission electron microscopy, are applied in the present study. A chitinous nature of the loricae is rejected by the Van-Wisselingh test and failure of chitinase digestion. Only proteins might show a resistance against strong hot bases (KOH at 160°C for ~ 40 min. in tintinnid loricae) similar to that of chitin. Actually, the presence of nitrogen in the EDX analyses and the digestion of at least some loricae by proteinase K strongly indicate a proteinaceous nature. Furthermore, the crystal lattice revealed by high-resolution TEM in Eutintinnus loricae is similar to the proteinaceous surface layer (S-layer) of archaea, and the striation recognizable in transverse sections of Eutintinnus loricae has a periodicity resembling that of the crystalline proteins in the extruded trichocysts of Paramecium and Frontonia. The proteolytic resistance of some loricae does not reject the idea of a proteinaceous nature, as proteins in S-layers of some archaea and in most naturally occurring prions show comparable reactions. The data from the present study and the literature indicate proteins in the loricae of thirteen genera. Differences in the proteolytic resistance and staining properties between genera and congeners are probably due to deviations in the protein composition and the additional substances, e.g. lipids, carbohydrates. At the present state of knowledge, correlations between lorica structure, wall texture, ultrastructure of the lorica forming granules, and the histochemical and enzymatic findings are not evident. Therefore, further studies are required to estimate the taxonomic significance of these features and the ecological role of sedimenting loricae.
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Affiliation(s)
- Sabine Agatha
- Department of Organismic Biology, University of Salzburg, Salzburg, Austria
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