1
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Roy-Chowdhury M, He C, Tang K, Koizumi H, Wen Z, Thota S, Sukegawa H, Ohkubo T, Mitani S. Conductive single-phase SrMoO 3 epitaxial films synthesized in pure Ar ambience via plasma-assisted radio frequency sputtering. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2024; 25:2378684. [PMID: 39135761 PMCID: PMC11318490 DOI: 10.1080/14686996.2024.2378684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 07/02/2024] [Accepted: 07/07/2024] [Indexed: 08/15/2024]
Abstract
The cubic perovskite SrMoO3 with a paramagnetic ground state and remarkably low room-temperature resistivity has been considered as a suitable candidate for the new-era oxide-based technology. However, the difficulty of preparing single-phase SrMoO3 thin films by hydrogen-free sputtering has hindered their practical use, especially due to the formation of thermodynamically favorable SrMoO4 impurity. In this work, we developed a radio frequency sputtering technology enabling the reduction reaction and achieved conductive epitaxial SrMoO3 films with pure phase from a SrMoO4 target in a hydrogen-free, pure argon environment. We demonstrated the significance of controlling the target-to-substrate distance (TSD) on the synthesis of SrMoO3; the film resistivity drastically changes from 1.46 × 105 μΩ·cm to 250 μΩ·cm by adjusting the TSD. Cross-sectional microstructural analyses demonstrated that films with the lowest resistivity, deposited for TSD = 2.5 cm, possess a single-phase SrMoO3 with an epitaxial perovskite structure. The formation mechanism of the conductive single-phase SrMoO3 films can be attributed to the plasma-assisted growth process by tuning the TSD. Temperature-dependent resistivity and Hall effect studies revealed metal-like conducting properties for low-resistive SrMoO3 films, while the high-resistive ones displayed semiconductor-like behavior. Our approach makes hydrogen-free, reliable and cost-efficient scalable deposition of SrMoO3 films possible, which may open up promising prospects for a wide range of future applications of oxide materials.
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Affiliation(s)
- Mouli Roy-Chowdhury
- Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan
- Department of Physics, Indian Institute of Technology Guwahati, Guwahati, India
| | - Cong He
- Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan
| | - Ke Tang
- Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan
- Graduate School of Science and Technology, University of Tsukuba, Tsukuba, Japan
| | - Hiroki Koizumi
- Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan
- Center for Science and Innovation in Spintronics (CSIS), Tohoku University, Sendai, Japan
| | - Zhenchao Wen
- Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan
| | - Subhash Thota
- Department of Physics, Indian Institute of Technology Guwahati, Guwahati, India
| | - Hiroaki Sukegawa
- Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan
| | - Tadakatsu Ohkubo
- Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan
| | - Seiji Mitani
- Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan
- Graduate School of Science and Technology, University of Tsukuba, Tsukuba, Japan
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2
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Thomsen JD, Wang Y, Flyvbjerg H, Park E, Watanabe K, Taniguchi T, Narang P, Ross FM. Direct Visualization of Defect-Controlled Diffusion in van der Waals Gaps. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2403989. [PMID: 39097947 DOI: 10.1002/adma.202403989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 07/15/2024] [Indexed: 08/06/2024]
Abstract
Diffusion processes govern fundamental phenomena such as phase transformations, doping, and intercalation in van der Waals (vdW) bonded materials. Here, the diffusion dynamics of W atoms by visualizing the motion of individual atoms at three different vdW interfaces: hexagonal boron nitride (BN)/vacuum, BN/BN, and BN/WSe2, by recording scanning transmission electron microscopy movies is quantified. Supported by density functional theory (DFT) calculations, it is inferred that in all cases diffusion is governed by intermittent trapping at electron beam-generated defect sites. This leads to diffusion properties that depend strongly on the number of defects. These results suggest that diffusion and intercalation processes in vdW materials are highly tunable and sensitive to crystal quality. The demonstration of imaging, with high spatial and temporal resolution, of layers and individual atoms inside vdW heterostructures offers possibilities for direct visualization of diffusion and atomic interactions, as well as for experiments exploring atomic structures, their in situ modification, and electrical property measurements of active devices combined with atomic resolution imaging.
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Affiliation(s)
- Joachim Dahl Thomsen
- Division of Physical Sciences, College of Letters and Science, University of California, Los Angeles, CL 90095, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Yaxian Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Henrik Flyvbjerg
- Mark Kac Center for Complex Systems Research, Jagiellonian University, Kraków, Poland
| | - Eugene Park
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Prineha Narang
- Division of Physical Sciences, College of Letters and Science, University of California, Los Angeles, CL 90095, USA
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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3
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Kreuz S, Apeleo Zubiri B, Englisch S, Buwen M, Kang SG, Ramachandramoorthy R, Spiecker E, Liers F, Rolfes J. Improving reconstructions in nanotomography for homogeneous materials via mathematical optimization. NANOSCALE ADVANCES 2024; 6:3934-3947. [PMID: 39050954 PMCID: PMC11265594 DOI: 10.1039/d3na01089a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 05/27/2024] [Indexed: 07/27/2024]
Abstract
Compressed sensing is an image reconstruction technique to achieve high-quality results from limited amount of data. In order to achieve this, it utilizes prior knowledge about the samples that shall be reconstructed. Focusing on image reconstruction in nanotomography, this work proposes enhancements by including additional problem-specific knowledge. In more detail, we propose further classes of algebraic inequalities that are added to the compressed sensing model. The first consists in a valid upper bound on the pixel brightness. It only exploits general information about the projections and is thus applicable to a broad range of reconstruction problems. The second class is applicable whenever the sample material is of roughly homogeneous composition. The model favors a constant density and penalizes deviations from it. The resulting mathematical optimization models are algorithmically tractable and can be solved to global optimality by state-of-the-art available implementations of interior point methods. In order to evaluate the novel models, obtained results are compared to existing image reconstruction methods, tested on simulated and experimental data sets. The experimental data comprise one 360° electron tomography tilt series of a macroporous zeolite particle and one absorption contrast nano X-ray computed tomography (nano-CT) data set of a copper microlattice structure. The enriched models are optimized quickly and show improved reconstruction quality, outperforming the existing models. Promisingly, our approach yields superior reconstruction results, particularly when only a small number of tilt angles is available.
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Affiliation(s)
- Sebastian Kreuz
- Department of Data Science, Friedrich-Alexander-Universität Erlangen-Nürnberg Cauerstr. 11 91058 Erlangen Germany
| | - Benjamin Apeleo Zubiri
- Institute of Micro- and Nanostructure Research (IMN) & Center for Nanoanalysis and Electron Microscopy (CENEM), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg Cauerstr. 3 91058 Erlangen Germany
| | - Silvan Englisch
- Institute of Micro- and Nanostructure Research (IMN) & Center for Nanoanalysis and Electron Microscopy (CENEM), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg Cauerstr. 3 91058 Erlangen Germany
| | - Moritz Buwen
- Institute of Micro- and Nanostructure Research (IMN) & Center for Nanoanalysis and Electron Microscopy (CENEM), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg Cauerstr. 3 91058 Erlangen Germany
| | - Sung-Gyu Kang
- Department Structure and Nano- / Micromechanics of Materials, Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Str. 1 40237 Düsseldorf Germany
- Department of Materials Engineering and Convergence Technology, Gyeongsang National University Jinju-daero 501 52828 Jinju Republic of Korea
| | - Rajaprakash Ramachandramoorthy
- Department Structure and Nano- / Micromechanics of Materials, Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Str. 1 40237 Düsseldorf Germany
| | - Erdmann Spiecker
- Institute of Micro- and Nanostructure Research (IMN) & Center for Nanoanalysis and Electron Microscopy (CENEM), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg Cauerstr. 3 91058 Erlangen Germany
| | - Frauke Liers
- Department of Data Science, Friedrich-Alexander-Universität Erlangen-Nürnberg Cauerstr. 11 91058 Erlangen Germany
| | - Jan Rolfes
- Department of Data Science, Friedrich-Alexander-Universität Erlangen-Nürnberg Cauerstr. 11 91058 Erlangen Germany
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4
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Ong CS, Donzel-Gargand O, Berastegui P, Cedervall J, Bayrak Pehlivan I, Hervoches C, Beran P, Edvinsson T, Eriksson O, Jansson U. The Crystal Structure of Al 4SiC 4 Revisited. Inorg Chem 2024; 63:10490-10499. [PMID: 38801717 PMCID: PMC11167590 DOI: 10.1021/acs.inorgchem.4c00560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/21/2024] [Accepted: 05/16/2024] [Indexed: 05/29/2024]
Abstract
Al4SiC4 is a ternary wide-band-gap semiconductor with a high strength-to-weight ratio and excellent oxidation resistance. It consists of slabs of Al4C3 separated by SiC layers with the space group of P63mc. The space group allows Si to occupy two different 2a Wykoff sites, with previous studies reporting that Si occupies only one of the two sites, giving it an ordered structure. Another hitherto unexplored possibility is that Si can be randomly distributed on both 2a sites. In this work, we revisit the published ordered crystal structure using experimental methods and density functional theory (DFT). Al4SiC4 was synthesized by high-temperature sintering at 1800 °C from a powder mixture of Al4C3 and SiC. Neutron diffraction confirmed that Al4SiC4 crystallized with the space group of P63mc, with diffraction patterns that could be fitted to both the ordered and the disordered structures. Scanning transmission electron microscopy, however, provided clear evidence supporting the latter, with DFT calculations further confirming that it is 0.16 eV lower in energy per Al4SiC4 formula unit than the former. TEM analysis revealed Al vacancies in some of the atomic layers that can introduce p-type doping and direct band gaps of 0.7 and 1.2 eV, agreeing with our optical measurements. Finally, we propose that although the calculated formation energy of the Al vacancies is high, the vacancies are stabilized by entropy effects at the high synthesis temperature. This indicates that the cooling procedure after high-temperature synthesis can be important in determining the vacancy content and the electronic properties of Al4SiC4.
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Affiliation(s)
- Chin Shen Ong
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, S-75120 Uppsala, Sweden
| | - Olivier Donzel-Gargand
- Division
of Solar Cell Technology, Department of Materials Science and Engineering, Uppsala University, S-75121 Uppsala, Sweden
| | - Pedro Berastegui
- Department
of Chemistry, Ångström Laboratory, Uppsala University, P.O. Box 538, S-75121 Uppsala, Sweden
| | - Johan Cedervall
- Department
of Chemistry, Ångström Laboratory, Uppsala University, P.O. Box 538, S-75121 Uppsala, Sweden
| | - Ilknur Bayrak Pehlivan
- Department
of Materials Science and Engineering, Ångström Laboratory, P.O. Box 35, S-75103 Uppsala, Sweden
| | | | - Premysl Beran
- Nuclear
Physics Institute CAS, Rez 25068, Czech Republic
- European
Spallation Source, ESS ERIC, S-221 00 Lund, Sweden
| | - Tomas Edvinsson
- Department
of Materials Science and Engineering, Ångström Laboratory, P.O. Box 35, S-75103 Uppsala, Sweden
| | - Olle Eriksson
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, S-75120 Uppsala, Sweden
- Wallenberg
Initiative Materials Science for Sustainability, Uppsala University, S-75121 Uppsala, Sweden
| | - Ulf Jansson
- Department
of Chemistry, Ångström Laboratory, Uppsala University, P.O. Box 538, S-75121 Uppsala, Sweden
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5
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Thomsen JD, Han MG, Penn AN, Foucher AC, Geiwitz M, Burch KS, Dekanovsky L, Sofer Z, Liu Y, Petrovic C, Ross FM, Zhu Y, Narang P. Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr 2Ge 2Te 6. ACS NANO 2024; 18:13458-13467. [PMID: 38739873 DOI: 10.1021/acsnano.3c09858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
van der Waals (vdW) magnetic materials, such as Cr2Ge2Te6 (CGT), show promise for memory and logic applications. This is due to their broadly tunable magnetic properties and the presence of topological magnetic features such as skyrmionic bubbles. A systematic study of thickness and oxidation effects on magnetic domain structures is important for designing devices and vdW heterostructures for practical applications. Here, we investigate thickness effects on magnetic properties, magnetic domains, and bubbles in oxidation-controlled CGT crystals. We find that CGT exposed to ambient conditions for 5 days forms an oxide layer approximately 5 nm thick. This oxidation leads to a significant increase in the oxidation state of the Cr ions, indicating a change in local magnetic properties. This is supported by real-space magnetic texture imaging through Lorentz transmission electron microscopy. By comparing the thickness-dependent saturation field of oxidized and pristine crystals, we find that oxidation leads to a nonmagnetic surface layer that is thicker than the oxide layer alone. We also find that the stripe domain width and skyrmionic bubble size are strongly affected by the crystal thickness in pristine crystals. These findings underscore the impact of thickness and surface oxidation on the properties of CGT, such as saturation field and domain/skyrmionic bubble size, and suggest a pathway for manipulating magnetic properties through a controlled oxidation process.
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Affiliation(s)
- Joachim Dahl Thomsen
- Division of Physical Sciences, College of Letters and Science, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Myung-Geun Han
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Aubrey N Penn
- MIT.nano, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alexandre C Foucher
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Michael Geiwitz
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Kenneth Stephen Burch
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Lukas Dekanovsky
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Zdeněk Sofer
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Yu Liu
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
- Center for Correlated Matter and School of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Cedomir Petrovic
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
- Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments (MFree), Shanghai Advanced Research in Physical Sciences (SHARPS), Pudong, Shanghai 201203, People's Republic of China
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yimei Zhu
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Prineha Narang
- Division of Physical Sciences, College of Letters and Science, University of California, Los Angeles, Los Angeles, California 90095, United States
- Electrical and Computer Engineering Department, University of California, Los Angeles, Los Angeles, California 90095, United States
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6
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Ye T, Wang Y, Yao X, Li H, Xiao T, Ba K, Tang Y, Zheng C, Yang X, Sun Z. Synthesis of Rhenium-Doped Copper Twin Boundary for High-Turnover-Frequency Electrochemical Nitrogen Reduction. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38706440 DOI: 10.1021/acsami.4c02259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
The precise design and synthesis of active sites to improve catalyst's performance has emerged as a promising tactic for electrochemistry. However, it is challenging to combine different types of active sites and manipulate them simultaneously at atomic resolution. Here, we present a strategy to synthesize Re atom-doped Cu twin boundaries (TBs), through pulsed electrodeposition and boundary segregation. The Re-doped Cu TBs demonstrate a highly efficient nitrogen reduction reaction (NRR) performance. Re-doped Cu TBs showed a turnover frequency of ∼5889 s-1, ∼800 times higher than the pure Cu TB active centers (∼7 s-1). In addition to the "acceptance-donation" activation of N2 molecules, theoretical calculations also reveal that the Re-Re dimer on TB can boost the NRR and impede the hydrogen evolution reaction synchronously, rendering Re-doped Cu TB catalysts with high NRR activity and selectivity.
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Affiliation(s)
- Tong Ye
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P. R. China
- School of Microelectronics and State Key Laboratory of ASIC and System, Fudan University, Shanghai 200433, P. R. China
| | - Yajie Wang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
| | - Xiang Yao
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P. R. China
| | - Hongbin Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P. R. China
| | - Taishi Xiao
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P. R. China
| | - Kun Ba
- School of Microelectronics and State Key Laboratory of ASIC and System, Fudan University, Shanghai 200433, P. R. China
| | - Yi Tang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P. R. China
| | - Changlin Zheng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
| | - Xiaoyong Yang
- School of National Defense Science and Technology, State Key Laboratory for Environment Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China
- Condensed Matter Theory Group, Materials Theory Division, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala 75120, Sweden
| | - Zhengzong Sun
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P. R. China
- School of Microelectronics and State Key Laboratory of ASIC and System, Fudan University, Shanghai 200433, P. R. China
- Yiwu Research Institute of Fudan University, Yiwu, Zhejiang 322000, P. R. China
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7
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Schwartz J, Di ZW, Jiang Y, Manassa J, Pietryga J, Qian Y, Cho MG, Rowell JL, Zheng H, Robinson RD, Gu J, Kirilin A, Rozeveld S, Ercius P, Fessler JA, Xu T, Scott M, Hovden R. Imaging 3D chemistry at 1 nm resolution with fused multi-modal electron tomography. Nat Commun 2024; 15:3555. [PMID: 38670945 PMCID: PMC11053043 DOI: 10.1038/s41467-024-47558-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/03/2024] [Indexed: 04/28/2024] Open
Abstract
Measuring the three-dimensional (3D) distribution of chemistry in nanoscale matter is a longstanding challenge for metrological science. The inelastic scattering events required for 3D chemical imaging are too rare, requiring high beam exposure that destroys the specimen before an experiment is completed. Even larger doses are required to achieve high resolution. Thus, chemical mapping in 3D has been unachievable except at lower resolution with the most radiation-hard materials. Here, high-resolution 3D chemical imaging is achieved near or below one-nanometer resolution in an Au-Fe3O4 metamaterial within an organic ligand matrix, Co3O4-Mn3O4 core-shell nanocrystals, and ZnS-Cu0.64S0.36 nanomaterial using fused multi-modal electron tomography. Multi-modal data fusion enables high-resolution chemical tomography often with 99% less dose by linking information encoded within both elastic (HAADF) and inelastic (EDX/EELS) signals. We thus demonstrate that sub-nanometer 3D resolution of chemistry is measurable for a broad class of geometrically and compositionally complex materials.
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Affiliation(s)
- Jonathan Schwartz
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Zichao Wendy Di
- Mathematics and Computer Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Yi Jiang
- Advanced Photon Source Facility, Argonne National Laboratory, Lemont, IL, USA
| | - Jason Manassa
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Jacob Pietryga
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Material Science and Engineering, Northwestern University, Evanston, IL, USA
| | - Yiwen Qian
- Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA, USA
| | - Min Gee Cho
- Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jonathan L Rowell
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Huihuo Zheng
- Argonne Leadership Computing Facility, Argonne National Laboratory, Lemont, IL, USA
| | - Richard D Robinson
- Department of Material Science and Engineering, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, USA
| | - Junsi Gu
- Dow Chemical Co., Collegeville, PA, USA
| | | | | | - Peter Ercius
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jeffrey A Fessler
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Ting Xu
- Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mary Scott
- Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA, USA.
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Robert Hovden
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA.
- Applied Physics Program, University of Michigan, Ann Arbor, MI, USA.
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8
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Zuo P, Wang F, Chen G, Wang C. Facet-Dependent Ni Segregation in a Micron-Sized Single-Crystal Li 1.2Ni 0.2Mn 0.6O 2 Cathode. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38651946 DOI: 10.1021/acsami.4c02885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Elemental surface segregation in cathode materials is critical for determining the phase and interfacial reaction between the electrode and electrolyte, which consequently affects the electrochemical properties. Single-crystal cathodes of Li1.2Ni0.2Mn0.6O2 and Li1.2Ni0.2Mn0.6O1.95F0.05 with octahedral morphologies of (102)- and (003)-dominated facets have been manifested to show enhanced electrochemical properties. However, the surface structural features of such single crystals have not been investigated. Herein, using scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, and electron energy loss spectroscopy, we probe the elemental surface segregation characteristics in these single-crystal cathodes. We reveal that Ni surface segregation shows dependence on the crystal facet such that it occurs on crystal facets with a mix of cations and anions but not on the facets with only cations or anions. Furthermore, facet-dependent surface reconstructions are observed, featuring a spinel-like structure at the Ni-rich facet but a rock-salt structure at the facet without Ni segregation. The commonly known Mn reduction appears at the single-crystal surfaces and is more pronounced at the facet without Ni segregation. We further reveal that fluorination leads to stabilization of surface oxygens. This study provides detailed structural and chemical information about the facet-dependent Ni surface segregation and the resulting phase formation in the rather less explored micron-sized octahedral Li1.2Ni0.2Mn0.6O2 and Li1.2Ni0.2Mn0.6O1.95F0.05 single crystals, which is key to further exploration of the electrochemical properties of the cathodes in the form of microsized single crystals.
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Affiliation(s)
- Peng Zuo
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Faxing Wang
- Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Guoying Chen
- Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Chongmin Wang
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
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9
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Zuo P, Badami P, Trask SE, Abraham DP, Wang C. Microstructural Insights into Performance Loss of High-Voltage Spinel Cathodes for Lithium-ion Batteries. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306807. [PMID: 37880877 DOI: 10.1002/smll.202306807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/02/2023] [Indexed: 10/27/2023]
Abstract
Spinel-structured LiNix Mn2-x O4 (LNMO), with low-cost earth-abundant constituents, is a promising high-voltage cathode material for lithium-ion batteries. Even though extensive electrochemical investigations have been conducted on these materials, few studies have explored correlations between their loss in performance and associated changes in microstructure. Here, down to the atomic scale, the structural evolution of these materials is investigated upon the progressive cycling of lithium-ion cells. Transgranular cracking is revealed to be a key feature during cycling; this cracking is initiated at the particle surface and leads to the penetration of electrolytes along the crack path, thereby increasing particle exposure to the electrolyte. The lattice structure on the crack surface shows spatial variances, featuring a top layer of rock-salt, a sublayer of a Mn3 O4 -like arrangement, and then a mixed-cation region adjacent to the bulk lattice. The transgranular cracking, along with the emergence of local lattice distortion, becomes more evident with extended cycling. Further, phase transformation at primary particle surfaces and void formation through vacancy condensation is found in the cycled samples. All these features collectively contribute to the performance degradation of the battery cells during electrochemical cycling.
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Affiliation(s)
- Peng Zuo
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99354, USA
| | - Pavan Badami
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, 60439, USA
| | - Stephen E Trask
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, 60439, USA
| | - Daniel P Abraham
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, 60439, USA
| | - Chongmin Wang
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99354, USA
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10
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Wang M, Chen D, Li Z, Wang Z, Huang S, Hai P, Tan Y, Zhuang X, Liu P. Epitaxial Growth of Two-Dimensional Nonlayered AuCrS 2 Materials via Au-Assisted Chemical Vapor Deposition. NANO LETTERS 2024; 24:2308-2314. [PMID: 38324009 DOI: 10.1021/acs.nanolett.3c04672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Two-dimensional (2D) nonlayered transition metal dichalcogenide (TMD) materials are emergent platforms for various applications from catalysis to quantum devices. However, their limited availability and nonstraightforward synthesis methods hinder our understanding of these materials. Here, we present a novel technique for synthesizing 2D nonlayered AuCrS2 via Au-assisted chemical vapor deposition (CVD). Our detailed structural analysis reveals the layer-by-layer growth of [AuCrS2] units atop an initial CrS2 monolayer, with Au binding to the adjacent monolayer of CrS2, which is in stark contrast with the well-known metal intercalation mechanism in the synthesis of many other 2D nonlayered materials. Theoretical calculations further back the crucial role of Cr in increasing the mobility of Au species and strengthening the adsorption energy of Au on CrS2, thereby aiding the growth throughout the CVD process. Additionally, the resulting free-standing nanoporous AuCrS2 (NP-AuCrS2) exhibits exceptional electrocatalytic properties for the hydrogen evolution reaction.
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Affiliation(s)
- Mengjia Wang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - DeChao Chen
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350108, P. R. China
| | - Zheng Li
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, P. R. China
| | - Ziqian Wang
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Senhe Huang
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Pengqi Hai
- School of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Yongwen Tan
- College of Materials Science and Engineering, State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, P. R. China
| | - Xiaodong Zhuang
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Pan Liu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
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11
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Şentürk DG, Yu CP, De Backer A, Van Aert S. Atom counting from a combination of two ADF STEM images. Ultramicroscopy 2024; 255:113859. [PMID: 37778104 DOI: 10.1016/j.ultramic.2023.113859] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/13/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023]
Abstract
To understand the structure-property relationship of nanostructures, reliably quantifying parameters, such as the number of atoms along the projection direction, is important. Advanced statistical methodologies have made it possible to count the number of atoms for monotype crystalline nanoparticles from a single ADF STEM image. Recent developments enable one to simultaneously acquire multiple ADF STEM images. Here, we present an extended statistics-based method for atom counting from a combination of multiple statistically independent ADF STEM images reconstructed from non-overlapping annular detector collection regions which improves the accuracy and allows one to retrieve precise atom-counts, especially for images acquired with low electron doses and multiple element structures.
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Affiliation(s)
- D G Şentürk
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - C P Yu
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - A De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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12
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Yang F, Wang Y, Cui Y, Yang X, Zhu Y, Weiss CM, Li M, Chen G, Yan Y, Gu MD, Shao M. Sub-3 nm Pt@Ru toward Outstanding Hydrogen Oxidation Reaction Performance in Alkaline Media. J Am Chem Soc 2023; 145:27500-27511. [PMID: 38056604 DOI: 10.1021/jacs.3c08908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
Anion-exchange membrane fuel cells (AEMFCs) are promising alternative hydrogen conversion devices. However, the sluggish kinetics of the hydrogen oxidation reaction in alkaline media hinders further development of AEMFCs. As a synthesis method commonly used to prepare disordered PtRu alloys, the impregnation process is ingeniously designed herein to synthesize sub-3 nm Pt@Ru core-shell nanoparticles by sequentially reducing Pt and Ru at different annealing temperatures. This method avoids complex procedures and synthesis conditions for organic synthesis systems, and the atomic structure evolution of the synthesized core-shell nanoparticles can be tracked. The synthesized Pt@Ru electrocatalyst shows an ultrasmall average size of ∼2.5 nm and thereby a large electrochemical surface area (ECSA) of 166.66 m2 gPt+Ru-1. Exchange current densities (j0) normalized to the mass (Pt + Ru) and ECSA of this electrocatalyst are 8.0 and 5.8 times as high as those of commercial Pt/C, respectively. To the best of our knowledge, the achieved mass-normalized j0 measured by rotating disk electrodes is the highest reported so far. The membrane electrode assembly test of the Pt@Ru electrocatalyst shows a peak power density of 1.78 W cm-2 (0.152 mgPt+Ru cmanode-2), which is higher than that of commercial PtRu/C (1.62 W cm-2, 0.211 mgPt+Ru cmanode-2). The improvement of the intrinsic activity can be attributed to the electron transfer from the Ru shell to the Pt core, and the ultrafine particles further enhance the mass activity. This work reveals the feasibility of using simple impregnation to synthesize fine core-shell nanocatalysts and the importance of investigating the atomic structure of PtRu nanoparticles and other disordered alloys.
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Affiliation(s)
- Fei Yang
- Eastern Institute for Advanced Study, Eastern Institute of Technology, Ningbo 315200, Zhejiang, China
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yian Wang
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
| | - Yingdan Cui
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
| | - Xuming Yang
- Graphene Composite Research Center, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Yuanmin Zhu
- Research Institute of Interdisciplinary Science & School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523808, China
| | - Catherine M Weiss
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Menghao Li
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guangyu Chen
- Fok Ying Tung Research Institute, The Hong Kong University of Science and Technology, Guangzhou 511458, China
| | - Yushan Yan
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - M Danny Gu
- Eastern Institute for Advanced Study, Eastern Institute of Technology, Ningbo 315200, Zhejiang, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Minhua Shao
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
- Fok Ying Tung Research Institute, The Hong Kong University of Science and Technology, Guangzhou 511458, China
- Energy Institute, and Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
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13
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Silinga A, Allen CS, Barthel J, Ophus C, MacLaren I. Measurement of Atomic Modulation Direction Using the Azimuthal Variation of First-Order Laue Zone Electron Diffraction. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1682-1687. [PMID: 37639214 DOI: 10.1093/micmic/ozad089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/12/2023] [Accepted: 08/02/2023] [Indexed: 08/29/2023]
Abstract
We show that diffraction intensity into the first-order Laue zone (FOLZ) of a crystal can have a strong azimuthal dependence, where this FOLZ ring appears solely because of unidirectional atom position modulation. Such a modulation was already known to cause the appearance of elliptical columns in atom-resolution images, but we show that measurement of the angle via four-dimensional scanning transmission electron microscopy (4DSTEM) is far more reliable and allows the measurement of the modulation direction with a precision of about 1° and an accuracy of about 3°. This method could be very powerful in characterizing atomic structures in three dimensions by 4DSTEM, especially in cases where the structure is found only in nanoscale regions or crystals.
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Affiliation(s)
- Aurys Silinga
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Christopher S Allen
- Electron Physical Science Imaging Centre, Diamond Light Source Ltd., Oxford OX11 0DE, UK
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Juri Barthel
- Ernst Ruska-Centre (ER-C 2), Forschungszentrum Jülich GmbH, Jülich 52425, Germany
| | - Colin Ophus
- NCEM, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ian MacLaren
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
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14
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Wang M, Luo R, Liu Y, Zhao X, Zhuang X, Xu WW, Chen M, Liu P. An unexpected interfacial Mo-rich phase in 2D molybdenum disulfide and 3D gold heterojunctions. NANOSCALE 2023; 15:14906-14911. [PMID: 37654188 DOI: 10.1039/d3nr01818k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The interface engineering of two-dimensional transition metal dichalcogenides (2D-TMDs) and metals has been regarded as a promising strategy to modulate their outstanding electrical and optoelectronic properties. Chemical Vapour Deposition (CVD) is an effective strategy to regulate the contact interface between TMDs and metals via directly growing 2D TMDs on a 3D metal substrate. Nevertheless, the underlying mechanisms of interfacial phase formation and evolution during TMD growth on a metallic substrate are less known. In this work, we found a 2D non-van der Waals (vdW) Mo-rich phase (MoNSN+1) during thermal sulfidation of a Mo-Au surface alloy to molybdenum disulfide (MoS2) in a S-poor environment. Systematic atomic-scale observations reveal that the periodic Mo and S atomic layers are arranged separating from each other in the non-vdW Mo-rich phase, and the Mo-rich phase preferentially nucleates between outmost 2D MoS2 and a 3D nanostructured Au substrate which possesses copious surface steps and kinks. Theoretical calculations demonstrate that the appearance of the Mo-rich phase with a unique metallic nature causes an n-type contact interface with an ultralow transition energy barrier height. This study may help understand the formation mechanism of the interfacial second phase during the epitaxial growth of 2D-TMDs on 3D nanostructured metals, and provide a new approach to tune the Schottky barrier height by the design of the interfacial phase structure at the heterojunction.
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Affiliation(s)
- Mengjia Wang
- Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
| | - Ruichun Luo
- School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuxin Liu
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China.
| | - Xiaoran Zhao
- Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
| | - Xiaodong Zhuang
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Wen Wu Xu
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China.
| | - Mingwei Chen
- Department of Materials Science and Engineering, Johns Hopkin University, Baltimore, MD 21218, USA.
| | - Pan Liu
- Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
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15
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Li G, Zhang H, Han Y. Applications of Transmission Electron Microscopy in Phase Engineering of Nanomaterials. Chem Rev 2023; 123:10728-10749. [PMID: 37642645 DOI: 10.1021/acs.chemrev.3c00364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Phase engineering of nanomaterials (PEN) is an emerging field that aims to tailor the physicochemical properties of nanomaterials by precisely manipulating their crystal phases. To advance PEN effectively, it is vital to possess the capability of characterizing the structures and compositions of nanomaterials with precision. Transmission electron microscopy (TEM) is a versatile tool that combines reciprocal-space diffraction, real-space imaging, and spectroscopic techniques, allowing for comprehensive characterization with exceptional resolution in the domains of time, space, momentum, and, increasingly, even energy. In this Review, we first introduce the fundamental mechanisms behind various TEM-related techniques, along with their respective application scopes and limitations. Subsequently, we review notable applications of TEM in PEN research, including applications in fields such as metallic nanostructures, carbon allotropes, low-dimensional materials, and nanoporous materials. Specifically, we underscore its efficacy in phase identification, composition and chemical state analysis, in situ observations of phase evolution, as well as the challenges encountered when dealing with beam-sensitive materials. Furthermore, we discuss the potential generation of artifacts during TEM imaging, particularly in scanning modes, and propose methods to minimize their occurrence. Finally, we offer our insights into the present state and future trends of this field, discussing emerging technologies including four-dimensional scanning TEM, three-dimensional atomic-resolution imaging, and electron microscopy automation while highlighting the significance and feasibility of these advancements.
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Affiliation(s)
- Guanxing Li
- Advanced Membranes and Porous Materials Center, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Hui Zhang
- Electron Microscopy Center, South China University of Technology, Guangzhou 510640, China
- School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Yu Han
- Advanced Membranes and Porous Materials Center, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- Electron Microscopy Center, South China University of Technology, Guangzhou 510640, China
- School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
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16
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Kim H, Choi H, Oh J, Lee S, Kwon H, Park ES, Lee S, Lee GD, Kim M, Han HN. Elucidating the role of a unique step-like interfacial structure of η 4 precipitates in Al-Zn-Mg alloy. SCIENCE ADVANCES 2023; 9:eadf7426. [PMID: 37267366 PMCID: PMC10413671 DOI: 10.1126/sciadv.adf7426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 04/27/2023] [Indexed: 06/04/2023]
Abstract
Al-Zn-Mg alloys are widely used in the transportation industry owing to their high strength-to-weight ratio. In these alloys, the main strengthening mechanism is precipitation hardening that occurs because of the formation of nano-sized precipitates. Herein, an interfacial structure of η4 precipitates, one of the main precipitates in these alloys, is revealed using aberration-corrected scanning transmission electron microscopy and first-principles calculations. These precipitates exhibit a pseudo-periodic steps and bridges. The results of this study demonstrate that the peculiar interface structure of η4/Al relieves the strain energy of η4 precipitates thus stabilizing them. The atomistic role of this interfacial structure in the nucleation and growth of the precipitates is elucidated. This study paves the way for tailoring the mechanical properties of alloys by controlling their precipitation kinetics.
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Affiliation(s)
| | | | - Juhyun Oh
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Sangmin Lee
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Ho Kwon
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | | | - Sungwoo Lee
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Gun-Do Lee
- Corresponding author. (H.N.H.); (M.K.); (G.-D.L.)
| | - Miyoung Kim
- Corresponding author. (H.N.H.); (M.K.); (G.-D.L.)
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17
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Zhang S, Liang D, Bai B, Zhang X, Li Y, Liu J, Zhang X, Zhang J. Quantifiable Regulation of Chemical Kinetics Barriers for Creation of Single-Atom Metal Sites on Photocatalytic Atomic Layers. J Phys Chem Lett 2023; 14:4357-4364. [PMID: 37140136 DOI: 10.1021/acs.jpclett.3c00830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cation exchange (CE) under mild conditions promises a facile strategy to anchor single metal sites on colloidal chalcogenides toward catalytic applications, which however has seldom been demonstrated. The dilemma behind this is the rapid kinetics and high efficiency of the reaction disfavoring atomic dispersion of the metal species. Here we report that a fine-tuning of the affinity between the incoming metal cations and the deliberately introduced ligands can be exploited to manipulate the kinetics of the CE reaction, in a quantitative and systematic manner defined by the Tolman electronic parameter of the ligands used. Moreover, the steric effect of metal-ligand complexes offers thermodynamic preference for spatial isolation of the metal atoms. These thereby allow the rational construction of single atom catalysts (SACs) via simple one-step CE reactions, as exemplified by the CE-derived incorporation of single metal atoms (M = Cu, Ag, Au, Pd) on SnS2 two-unit-cell layers through M-S coordination.
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Affiliation(s)
- Shuping Zhang
- School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, MIIT Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, MOE Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, China
| | - Danli Liang
- School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, MIIT Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, MOE Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, China
| | - Bing Bai
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Xiuming Zhang
- School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, MIIT Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, MOE Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yuemei Li
- School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, MIIT Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, MOE Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, China
| | - Jia Liu
- School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, MIIT Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, MOE Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, China
| | - Xiuhui Zhang
- School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, MIIT Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, MOE Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, China
| | - Jiatao Zhang
- School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, MIIT Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, MOE Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, China
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18
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Han X, You JY, Wu S, Li R, Feng YP, Loh KP, Zhao X. Atomically Unveiling an Atlas of Polytypes in Transition-Metal Trihalides. J Am Chem Soc 2023; 145:3624-3635. [PMID: 36735914 DOI: 10.1021/jacs.2c12801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Transition-metal trihalides MX3 (M = Cr, Ru; X = Cl, Br, and I) belong to a family of novel two-dimensional (2D) magnets that can exhibit topological magnons and electromagnetic properties, thus affording great promises in next-generation spintronic devices. Rich magnetic ground states observed in the MX3 family are believed to be strongly correlated to the signature Kagome lattice and interlayer van der Waals coupling raised from distinct stacking orders. However, the intrinsic air instability of MX3 makes their direct atomic-scale analysis challenging. Therefore, information on the stacking-registry-dependent magnetism for MX3 remains elusive, which greatly hinders the engineering of desired phases. Here, we report a nondestructive transfer method and successfully realize an intact transfer of bilayer MX3, as evidenced by scanning transmission electron microscopy (STEM). After surveying hundreds of MX3 thin flakes, we provide a full spectrum of stacking orders in MX3 with atomic precision and calculated their associated magnetic ground states, unveiled by combined STEM and density functional theory (DFT). In addition to well-documented phases, we discover a new monoclinic C2/c phase in the antiferromagnetic (AFM) structure widely existing in MX3. Rich stacking polytypes, including C2/c, C2/m, R3̅, P3112, etc., provide rich and distinct magnetic ground states in MX3. Besides, a high density of strain soliton boundaries is consistently found in all MX3, combined with likely inverted structures, allowing AFM to ferromagnetic (FM) transitions in most MX3. Therefore, our study sheds light on the structural basis of diverse magnetic orders in MX3, paving the way for modulating magnetic couplings via stacking engineering.
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Affiliation(s)
- Xiaocang Han
- School of Materials Science and Engineering, Peking University, Beijing100871, China
| | - Jing-Yang You
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551Singapore
| | - Shengqiang Wu
- School of Materials Science and Engineering, Peking University, Beijing100871, China
| | - Runlai Li
- College of Polymer Science & Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu610065, China
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551Singapore
| | - Kian Ping Loh
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, 999077, China
| | - Xiaoxu Zhao
- School of Materials Science and Engineering, Peking University, Beijing100871, China
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19
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Hu Y, Anandkumar M, Joardar J, Wang X, Deshpande AS, Reddy KM. Effective band gap engineering in multi-principal oxides (CeGdLa-Zr/Hf)O x by temperature-induced oxygen vacancies. Sci Rep 2023; 13:2362. [PMID: 36759551 PMCID: PMC9911753 DOI: 10.1038/s41598-023-29477-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Oxygen vacancy control has been one of the most efficient methods to tune the physicochemical properties of conventional oxide materials. A new conceptual multi-principal oxide (MPO) is still lacking a control approach to introduce oxygen vacancies for tuning its inherent properties. Taking multi-principal rare earth-transition metal (CeGdLa-Zr/Hf) oxides as model systems, here we report temperature induced oxygen vacancy generation (OVG) phenomenon in MPOs. It is found that the OVG is strongly dependent on the composition of the MPOs showing different degrees of oxygen loss in (CeGdLaZr)Ox and (CeGdLaHf)Ox under identical high temperature annealing conditions. The results revealed that (CeGdLaZr)Ox remained stable single phase with a marginal decrease in the band gap of about 0.08 eV, whereas (CeGdLaHf)Ox contained two phases with similar crystal structure but different oxygen vacancy concentrations causing semiconductor-to-metal like transition. Due to the intrinsic high entropy, the metallic atoms sublattice in (CeGdLaHf)Ox remains rather stable, regardless of the interstitial oxygen atoms ranging from almost fully occupied (61.84 at%) to almost fully empty (8.73 at%) state in the respective crystal phases. Such highly tunable oxygen vacancies in (CeGdLa-Zr/Hf) oxides show a possible path for band gap engineering in MPOs for the development of efficient photocatalysts.
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Affiliation(s)
- Yixuan Hu
- grid.16821.3c0000 0004 0368 8293State Key Laboratory for Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Mariappan Anandkumar
- grid.459612.d0000 0004 1767 065XDepartment of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad, Sangareddy, 502285 India
| | - Joydip Joardar
- grid.466869.30000 0001 1135 5593International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad, Telangana 500005 India
| | - Xiaodong Wang
- grid.16821.3c0000 0004 0368 8293State Key Laboratory for Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Atul Suresh Deshpande
- grid.459612.d0000 0004 1767 065XDepartment of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad, Sangareddy, 502285 India
| | - Kolan Madhav Reddy
- State Key Laboratory for Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
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20
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Cao Y, Tang YL, Zhu YL, Wang Y, Liu N, Zou MJ, Liu J, Feng YP, Geng WR, Ma XL. Achieving High-Temperature Multiferroism by Atomic Architecture. ACS APPLIED MATERIALS & INTERFACES 2023; 15:3163-3171. [PMID: 36621962 DOI: 10.1021/acsami.2c20122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Materials with multiple order parameters, typically, in which ferroelectricity and magnetism are coupled, are illuminative for next-generation multifunctional electronics. However, searching for such single-phase multiferroics is challenging owing to antagonistic orbital occupancy and chemical bonding requirements for polarity and magnetism. Appropriate multiferroic candidates have been proposed, but their practical implementation is impeded by the low working temperature, weak coupling between ferroic orders, or antiparallel spin alignment in magnetic sublattices. Here, we report a family of single-phase multiferroic materials in which high-temperature magnetism and voltage-switchable ferroelectricity are coupled. Using pulsed laser deposition, we have fabricated single-crystalline thin films incorporating a uniformly percolated open-shell dn framework, which are composed of Fe cations with B-site occupancy and exhibit long-range spin ordering into the displacive ferroelectric PbTiO3 lattice, as demonstrated by atomically resolved chemical analysis. The tetragonal polar Pb(Ti1-x,Fex)O3 (PFT(x), x ≤ 0.10) family exhibits a switchable ferroelectric nature and magnetic interaction with a moderate coercive field of around 300 Oe at room temperature. Notably, the magnetic order even persists above 500 K, which is higher than already reported potential multiferroic candidates until now. Our strategy of merging a spin-ordered sublattice into inherent ferroelectrics via atomic occupancy engineering provides an available pathway for highly thermally stable multiferroic and spintronic applications.
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Affiliation(s)
- Yi Cao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Yin-Lian Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Yujia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Nan Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Min-Jie Zou
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiaqi Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yan-Peng Feng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wan-Rong Geng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiu-Liang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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21
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De Backer A, Zhang Z, van den Bos KHW, Bladt E, Sánchez-Iglesias A, Liz-Marzán LM, Nellist PD, Bals S, Van Aert S. Element Specific Atom Counting at the Atomic Scale by Combining High Angle Annular Dark Field Scanning Transmission Electron Microscopy and Energy Dispersive X-ray Spectroscopy. SMALL METHODS 2022; 6:e2200875. [PMID: 36180399 DOI: 10.1002/smtd.202200875] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/29/2022] [Indexed: 06/16/2023]
Abstract
A new methodology is presented to count the number of atoms in multimetallic nanocrystals by combining energy dispersive X-ray spectroscopy (EDX) and high angle annular dark field scanning transmission electron microscopy (HAADF STEM). For this purpose, the existence of a linear relationship between the incoherent HAADF STEM and EDX images is exploited. Next to the number of atoms for each element in the atomic columns, the method also allows quantification of the error in the obtained number of atoms, which is of importance given the noisy nature of the acquired EDX signals. Using experimental images of an Au@Ag core-shell nanorod, it is demonstrated that 3D structural information can be extracted at the atomic scale. Furthermore, simulated data of an Au@Pt core-shell nanorod show the prospect to characterize heterogeneous nanostructures with adjacent atomic numbers.
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Affiliation(s)
- Annick De Backer
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Zezhong Zhang
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Karel H W van den Bos
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Eva Bladt
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Ana Sánchez-Iglesias
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014, Donostia-San Sebastián, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 20014, Donostia-San Sebastián, Spain
| | - Luis M Liz-Marzán
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014, Donostia-San Sebastián, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 20014, Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Peter D Nellist
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Sara Bals
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Sandra Van Aert
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
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22
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Li P, Bu Y, Wang L, Wang C, Huang J, Tong K, Chen Y, He J, Zhao Z, Xu B, Liu Z, Gao G, Nie A, Wang H, Tian Y. In Situ Observation of Fracture along Twin Boundaries in Boron Carbide. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2204375. [PMID: 36099908 DOI: 10.1002/adma.202204375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 09/09/2022] [Indexed: 06/15/2023]
Abstract
The observation of fracture behaviors in perfect and twinned B4 C crystals via in situ transmission electron microscopy (TEM) mechanical testing is reported. The crystal structure of the synthesized B4 C, composed of B11 C icosahedra connected by boron-deficient C-▫-C chains in a chemical formula of B11 C3 , is determined by state-of-the-art aberration-corrected scanning TEM. The in situ TEM observations reveal that cracking is preferentially initiated at the twin boundaries (TBs) in B4 C under both indentation and tension loading. The cracks then propagate along the TBs, thus resulting in the fracture of B4 C. These results are consistent with the theoretical calculations that show that TBs have a softening effect on B4 C with amorphous bands preferentially nucleated at the TBs. These findings elucidate the atomic arrangement and the role of planar defects in the failure of B4 C. Furthermore, they can guide the design of advanced superhard materials via planar defect control.
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Affiliation(s)
- Penghui Li
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Yeqiang Bu
- Center for X-mechanics, Institute of Applied Mechanics, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Linyan Wang
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Chong Wang
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Junquan Huang
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Ke Tong
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Yujun Chen
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Julong He
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Zhisheng Zhao
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Bo Xu
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Zhongyuan Liu
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Guoying Gao
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Anmin Nie
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Hongtao Wang
- Center for X-mechanics, Institute of Applied Mechanics, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Yongjun Tian
- Center for High Pressure Science, State Key Lab of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China
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23
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Liu H, Silva WC, Santana Gonçalves de Souza L, Veiga AG, Seixas L, Fujisawa K, Kahn E, Zhang T, Zhang F, Yu Z, Thompson K, Lei Y, de Matos CJS, Rocco MLM, Terrones M, Grasseschi D. 3d transition metal coordination on monolayer MoS 2: a facile doping method to functionalize surfaces. NANOSCALE 2022; 14:10801-10815. [PMID: 35735180 DOI: 10.1039/d2nr01132h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Two-dimensional materials (2DM) have attracted much interest due to their distinct optical, electronic, and catalytic properties. These properties can be tuned by a range of methods including substitutional doping and, as recently demonstrated, by surface functionalization with single atoms, thus increasing the 2DM portfolio. We theoretically and experimentally describe the coordination reaction between MoS2 monolayers and 3d transition metals (TMs), exploring their nature and MoS2-TM interactions. Density functional theory calculations, X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy point to the formation of MoS2-TM coordination complexes, where the adsorption energy for 3d TMs resembles the crystal-field (CF) stabilization energy for weak-field complexes. Pearson's theory for hard-soft acid-base and ligand-field theory were used to discuss the periodic trends of 3d TM coordination on MoS2 monolayer surfaces. We found that softer acids with higher ligand field stabilization energy, such as Ni2+, tend to form bonds with more covalent character with MoS2, which can be considered a soft base. On the other hand, harder acids, such as Cr3+, tend to form more ionic bonds. Additionally, we studied the trends in charge transfer and doping observed from XPS and PL results, where metals like Ni led to n-type doping. In contrast, Cu functionalization results in p-type doping. Therefore, the formation of coordination complexes on TMD's surface is a potentially effective way to control and understand the nature of single-atom functionalization of TMD monolayers without relying on or creating new defects.
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Affiliation(s)
- He Liu
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.
| | - Walner Costa Silva
- Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), 21941-909, Rio de Janeiro, Brazil.
| | | | - Amanda Garcez Veiga
- Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), 21941-909, Rio de Janeiro, Brazil.
| | - Leandro Seixas
- MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian Institute, 01302-907, São Paulo, Brazil
- Engineering School, Mackenzie Presbyterian University, 01302-907, São Paulo, Brazil
| | - Kazunori Fujisawa
- Research Initiative for Supra-Materials (RISM), Shinshu University, 4-17-1 Wakasato, Nagano, 380-8553, Japan
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ethan Kahn
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Tianyi Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Fu Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Zhuohang Yu
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Katherine Thompson
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.
| | - Yu Lei
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Christiano J S de Matos
- MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian Institute, 01302-907, São Paulo, Brazil
- Engineering School, Mackenzie Presbyterian University, 01302-907, São Paulo, Brazil
| | - Maria Luiza M Rocco
- Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), 21941-909, Rio de Janeiro, Brazil.
| | - Mauricio Terrones
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Daniel Grasseschi
- Institute of Chemistry, Federal University of Rio de Janeiro (UFRJ), 21941-909, Rio de Janeiro, Brazil.
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24
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Yang P, Li Z, Yang Y, Li R, Qin L, Zou Y. Effects of Electron Microscope Parameters and Sample Thickness on High Angle Annular Dark Field Imaging. SCANNING 2022; 2022:8503314. [PMID: 35360524 PMCID: PMC8958084 DOI: 10.1155/2022/8503314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Scanning transmission electron microscopy (STEM) developed into a very important characterization tool for atomic analysis of crystalline specimens. High-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) has become one of the most powerful tools to visualize material structures at atomic resolution. However, the parameter of electron microscope and sample thickness is the important influence factors on HAADF-STEM imaging. The effect of convergence angle, spherical aberration, and defocus to HAADF imaging process has been analyzed through simulation. The applicability of two HAADF simulation software has been compared, and suggestions for their usage have been given.
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Affiliation(s)
- Pucheng Yang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Zheng Li
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Yi Yang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Rui Li
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Lufei Qin
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Yunhao Zou
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
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25
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AutomAl 6000: Semi-automatic structural labeling of HAADF-STEM images of precipitates in Al-Mg-Si(-Cu) alloys. Ultramicroscopy 2022; 236:113493. [DOI: 10.1016/j.ultramic.2022.113493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/11/2022] [Accepted: 02/15/2022] [Indexed: 11/21/2022]
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26
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Zschiesche H, Aygar AM, Langelier B, Szkopek T, Botton GA. Atomic scale chemical ordering in franckeite-a natural van der Waals superlattice. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:055403. [PMID: 34783682 DOI: 10.1088/1361-648x/ac3451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
The mineral franckeite is a naturally occurring van der Waals superlattice which has recently attracted attention for future applications in optoelectronics, biosensors and beyond. Furthermore, its stacking of incommensurately modulated 2D layers, the pseudo tetragonal Q-layer and the pseudo hexagonal H-layer, is an experimentally accessible prototype for the development of synthetic van der Waals materials and of advanced characterization methods to reveal new insights in their structure and chemistry at the atomic scale that is crucial for deep understanding of its properties. While some experimental studies have been undertaken in the past, much is still unknown on the correlation between local atomic structure and chemical composition within the layers. Here we present an investigation of the atomic structure of franckeite using state-of-the-art high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) and atom probe tomography (APT). With atomic-number image contrast in HAADF STEM direct information about both the geometric structure and its chemistry is provided. By imaging samples under different zone axes within the van der Waals plane, we propose refinements to the structure of the Q-layer and H-layer, including several chemical ordering effects that are expected to impact electronic structure calculations. Additionally, we observe and characterize stacking faults which are possible sources of differences between experimentally determined properties and calculations. Furthermore, we demonstrate advantages and discuss current limitations and perspectives of combining TEM and APT for the atomic scale characterization of incommensurately modulated von der Waals materials.
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Affiliation(s)
- Hannes Zschiesche
- McMaster University, Department of Materials Science and Engineering, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada
| | - Ayse Melis Aygar
- McGill University, Department of Electrical and Computer Engineering, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Brian Langelier
- McMaster University, Canadian Center for Electron microscopy, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada
| | - Thomas Szkopek
- McGill University, Department of Electrical and Computer Engineering, 3480 Rue University, Montreal, QC H3A 2A7, Canada
| | - Gianluigi A Botton
- McMaster University, Department of Materials Science and Engineering, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada
- Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, SK S7N 2V3, Canada
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27
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Modelling ADF STEM images using elliptical Gaussian peaks and its effects on the quantification of structure parameters in the presence of sample tilt. Ultramicroscopy 2021; 230:113391. [PMID: 34600202 DOI: 10.1016/j.ultramic.2021.113391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/03/2021] [Accepted: 09/09/2021] [Indexed: 11/20/2022]
Abstract
A small sample tilt away from a main zone axis orientation results in an elongation of the atomic columns in ADF STEM images. An often posed research question is therefore whether the ADF STEM image intensities of tilted nanomaterials should be quantified using a parametric imaging model consisting of elliptical rather than the currently used symmetrical peaks. To this purpose, simulated ADF STEM images corresponding to different amounts of sample tilt are studied using a parametric imaging model that consists of superimposed 2D elliptical Gaussian peaks on the one hand and symmetrical Gaussian peaks on the other hand. We investigate the quantification of structural parameters such as atomic column positions and scattering cross sections using both parametric imaging models. In this manner, we quantitatively study what can be gained from this elliptical model for quantitative ADF STEM, despite the increased parameter space and computational effort. Although a qualitative improvement can be achieved, no significant quantitative improvement in the estimated structure parameters is achieved by the elliptical model as compared to the symmetrical model. The decrease in scattering cross sections with increasing sample tilt is even identical for both types of parametric imaging models. This impedes direct comparison with zone axis image simulations. Nonetheless, we demonstrate how reliable atom-counting can still be achieved in the presence of small sample tilt.
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28
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The effect of the Mo/W ratio on the catalytic properties of alumina supported hydrotreating catalysts prepared from mixed SiMo6W6 and SiMo9W3 heteropolyacids. Catal Today 2021. [DOI: 10.1016/j.cattod.2020.07.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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29
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Genevois C, Bazzaoui H, Boyer M, Ory S, Ledemi Y, Messaddeq Y, Pitcher MJ, Allix M. Emergence of A-Site Cation Order in the Small Rare-Earth Melilites Sr REGa 3O 7 ( RE = Dy-Lu, Y). Inorg Chem 2021; 60:12339-12354. [PMID: 34346214 DOI: 10.1021/acs.inorgchem.1c01565] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
SrREGa3O7 melilite ceramics with large rare-earth elements (RE = La to Y) are famous materials especially known for their luminescence properties. Using an innovative approach, the full and congruent crystallization from glass process, SrREGa3O7 transparent polycrystalline ceramics with small rare earth elements (RE = Dy-Lu and Y) have been successfully synthesized and characterized. Interestingly, compared to the classic tetragonal (P4̅21m) melilite structure composed of mixed Sr/RE cationic sites, these compositions can crystallize in a 3 × 1 × 1 orthorhombic (P21212) superstructure. A detailed study of the superstructure, investigated using different techniques (synchrotron and neutron powder diffraction, STEM-HAADF imaging, and EDS mapping), highlights the existence of a Sr/RE cation ordering favored by a large Sr/RE size mismatch and a sufficiently small RE cation. An appropriate control of the synthesis conditions through glass crystallization enables the formation of the desired polymorphs, either ordered or disordered. The influence of this tailored cationic ordering/disordering on the RE luminescent spectroscopic properties have been investigated. A stronger structuration of the RE emission band is observed in the ordered ceramic compared to the disordered ceramic and the glass, whose band shapes are very similar, indicating that the RE environments in the glass and disordered ceramic are close.
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Affiliation(s)
- Cécile Genevois
- CNRS, CEMHTI UPR 3079, Université Orléans, F-45071 Orléans, France
| | - Haytem Bazzaoui
- CNRS, CEMHTI UPR 3079, Université Orléans, F-45071 Orléans, France
| | - Marina Boyer
- CNRS, CEMHTI UPR 3079, Université Orléans, F-45071 Orléans, France
| | - Sandra Ory
- CNRS, CEMHTI UPR 3079, Université Orléans, F-45071 Orléans, France
| | - Yannick Ledemi
- Center for Optics, Photonics and Laser, Université Laval, Quebec City, Canada
| | - Younès Messaddeq
- Center for Optics, Photonics and Laser, Université Laval, Quebec City, Canada
| | | | - Mathieu Allix
- CNRS, CEMHTI UPR 3079, Université Orléans, F-45071 Orléans, France
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30
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Takada K, Morita M, Imaoka T, Kakinuma J, Albrecht K, Yamamoto K. Metal atom-guided conformational analysis of single polynuclear coordination molecules. SCIENCE ADVANCES 2021; 7:7/32/eabd9887. [PMID: 34362728 PMCID: PMC8346213 DOI: 10.1126/sciadv.abd9887] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Microscopic observation of single molecules is a rapidly expanding field in chemistry and differs from conventional characterization techniques that require a large number of molecules. One of such form of single-molecule microscopy is high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), which is especially suitable for coordination compounds because of its atomic number-dependent contrast. However, to date, single-molecule observations using HAADF-STEM has limited to simple planar molecules. In the present study, we demonstrate a direct structural investigation of nonplanar dendronized polynuclear Ir complexes with subnanometer resolution using Ir as an atomic label. Decreasing the electron dose to the dendrimer complexes is critical for the single-molecule observation. A comparison with simulated STEM images of conformational isomers is performed to determine the most plausible conformation. Our results enlarge the potential of electron microscopic observation to realize structural analysis of coordination macromolecules, which has been impossible with conventional methods.
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Affiliation(s)
- Kenji Takada
- JST ERATO, Yamamoto Atom Hybrid Project, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Mari Morita
- JST ERATO, Yamamoto Atom Hybrid Project, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Takane Imaoka
- JST ERATO, Yamamoto Atom Hybrid Project, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
- Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Junko Kakinuma
- JST ERATO, Yamamoto Atom Hybrid Project, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Ken Albrecht
- JST ERATO, Yamamoto Atom Hybrid Project, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
- Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Kimihisa Yamamoto
- JST ERATO, Yamamoto Atom Hybrid Project, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
- Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
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31
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Hofer C, Skákalová V, Haas J, Wang X, Braun K, Pennington RS, Meyer JC. Atom-by-atom chemical identification from scanning transmission electron microscopy images in presence of noise and residual aberrations. Ultramicroscopy 2021; 227:113292. [PMID: 33992503 DOI: 10.1016/j.ultramic.2021.113292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/14/2021] [Accepted: 04/20/2021] [Indexed: 10/21/2022]
Abstract
The simple dependence of the intensity in annular dark field scanning transmission electron microscopy images on the atomic number provides (to some extent) chemical information about the sample, and even allows an elemental identification in the case of light-element single-layer samples. However, the intensity of individual atoms and atomic columns is affected by residual aberrations and the confidence of an identification is limited by the available signal to noise. Here, we show that matching a simulation to an experimental image by iterative optimization provides a reliable analysis of atomic intensities even in presence of residual non-round aberrations. We compare our new method with other established approaches demonstrating its high reliability for images recorded at limited dose and with different aberrations. This is of particular relevance for analyzing moderately beam-sensitive materials, such as most 2D materials, where the limited sample stability often makes it difficult to obtain spectroscopic information at atomic resolution.
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Affiliation(s)
- Christoph Hofer
- Institute for Applied Physics, Eberhard Karls University of Tübingen, Auf der Morgenstelle 10, D-72076, Tübingen, Germany; Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, D-72770 Reutlingen, Germany; Faculty of Physics, University of Vienna, Boltzmanng. 5, 1090 Vienna, Austria.
| | - Viera Skákalová
- Faculty of Physics, University of Vienna, Boltzmanng. 5, 1090 Vienna, Austria
| | - Jonas Haas
- Institute for Applied Physics, Eberhard Karls University of Tübingen, Auf der Morgenstelle 10, D-72076, Tübingen, Germany; Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, D-72770 Reutlingen, Germany
| | - Xiao Wang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Kai Braun
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University of Tübingen, Auf der Morgenstelle 10, D-72076, Tübingen, Germany
| | - Robert S Pennington
- Institute for Applied Physics, Eberhard Karls University of Tübingen, Auf der Morgenstelle 10, D-72076, Tübingen, Germany; Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, D-72770 Reutlingen, Germany
| | - Jannik C Meyer
- Institute for Applied Physics, Eberhard Karls University of Tübingen, Auf der Morgenstelle 10, D-72076, Tübingen, Germany; Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, D-72770 Reutlingen, Germany; Faculty of Physics, University of Vienna, Boltzmanng. 5, 1090 Vienna, Austria
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32
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Nord M, Barthel J, Allen CS, McGrouther D, Kirkland AI, MacLaren I. Atomic resolution HOLZ-STEM imaging of atom position modulation in oxide heterostructures. Ultramicroscopy 2021; 226:113296. [PMID: 34004555 DOI: 10.1016/j.ultramic.2021.113296] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 03/16/2021] [Accepted: 04/24/2021] [Indexed: 11/26/2022]
Abstract
It is shown that higher order Laue zone (HOLZ) rings in high energy electron diffraction are specific to individual columns of atoms, and show different strengths, structure and radii for different atom columns along the same projection in a structure. An atomic resolution 4-dimensional STEM dataset is recorded from a <110> direction in a perovskite trilayer, where only the central LaFeO3 layer should show a period doubling that gives rise to an extra HOLZ ring. Careful comparison between experiment and multislice simulations is used to understand the origins of all features in the patterns. A strong HOLZ ring is seen for the La-O columns, indicating strong La position modulation along this direction, whereas a weaker ring is seen along the O columns, and a very weak ring is seen along the Fe columns. This demonstrates that atomic resolution HOLZ-STEM is a feasible method for investigating the 3D periodicity of crystalline materials with atomic resolution.
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Affiliation(s)
- Magnus Nord
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK; Department of Physics, NTNU, Høgskoleringen 5, 7491, Trondheim, Norway
| | - Juri Barthel
- Ernst Ruska-Centre (ER-C 2), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Christopher S Allen
- electron Physical Science Imaging Centre, Diamond Light Source Ltd., OX11 0DE, UK; Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Damien McGrouther
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Angus I Kirkland
- electron Physical Science Imaging Centre, Diamond Light Source Ltd., OX11 0DE, UK; Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Ian MacLaren
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK.
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33
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Mukherjee P, Lu P, Faenza N, Pereira N, Amatucci G, Ceder G, Cosandey F. Atomic Structure of Surface-Densified Phases in Ni-Rich Layered Compounds. ACS APPLIED MATERIALS & INTERFACES 2021; 13:17478-17486. [PMID: 33844491 DOI: 10.1021/acsami.1c00143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this work, we report the presence of surface-densified phases (β-Ni5O8, γ-Ni3O4, and δ-Ni7O8) in LiNiO2 (LNO)- and LiNi0.8Al0.2O2 (LNA)-layered compounds by combined atomic level scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS). These surface phases form upon electrochemical aging at high state of charge corresponding to a fully delithiated state. A unique feature of these phases is the periodic occupancy by Ni2+ in the Li layer. This periodic Ni occupancy gives rise to extra diffraction reflections, which are qualitatively similar to those of the LiNi2O4 spinel structure, but these surface phases have a lower Ni valence state and cation content than spinel. These experimental results confirm the presence of thermodynamically stable surface phases and provide new insights into the phenomena of surface phase formation in Ni-rich layered structures.
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Affiliation(s)
- Pinaki Mukherjee
- Materials Science and Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Ping Lu
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Nicholas Faenza
- Energy Storage Research Group, Rutgers University, Newark, New Jersey 08902, United States
| | - Nathalie Pereira
- Energy Storage Research Group, Rutgers University, Newark, New Jersey 08902, United States
| | - Glenn Amatucci
- Energy Storage Research Group, Rutgers University, Newark, New Jersey 08902, United States
| | - Gerbrand Ceder
- Materials Science and Engineering, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Frederic Cosandey
- Materials Science and Engineering, Rutgers University, Newark, New Jersey 08854, United States
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34
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Unusual solute segregation phenomenon in coherent twin boundaries. Nat Commun 2021; 12:722. [PMID: 33526770 PMCID: PMC7851144 DOI: 10.1038/s41467-021-21104-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 01/12/2021] [Indexed: 11/08/2022] Open
Abstract
Interface segregation of solute atoms has a profound effect on properties of engineering alloys. The occurrence of solute segregation in coherent twin boundaries (CTBs) in Mg alloys is commonly considered to be induced by atomic size effect where solute atoms larger than Mg take extension sites and those smaller ones take compression sites in CTBs. Here we report an unusual solute segregation phenomenon in a group of Mg alloys-solute atoms larger than Mg unexpectedly segregate to compression sites of {10[Formula: see text]1} fully coherent twin boundary and do not segregate to the extension or compression site of {10[Formula: see text]2} fully coherent twin boundary. We propose that such segregation is dominated by chemical bonding (coordination and solute electronic configuration) rather than elastic strain minimization. We further demonstrate that the chemical bonding factor can also predict the solute segregation phenomena reported previously. Our findings advance the atomic-level understanding of the role of electronic structure in solute segregation in fully coherent twin boundaries, and more broadly grain boundaries, in Mg alloys. They are likely to provide insights into interface boundaries in other metals and alloys of different structures.
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35
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Kosasih FU, Cacovich S, Divitini G, Ducati C. Nanometric Chemical Analysis of Beam-Sensitive Materials: A Case Study of STEM-EDX on Perovskite Solar Cells. SMALL METHODS 2021; 5:e2000835. [PMID: 34927887 DOI: 10.1002/smtd.202000835] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/25/2020] [Indexed: 06/14/2023]
Abstract
Quantitative chemical analysis on the nanoscale provides valuable information on materials and devices which can be used to guide further improvements to their performance. In particular, emerging families of technologically relevant composite materials such as organic-inorganic hybrid halide perovskites and metal-organic frameworks stand to benefit greatly from such characterization. However, these nanocomposites are also vulnerable to damage induced by analytical probes such as electron, X-ray, or neutron beams. Here the effect of electrons on a model hybrid halide perovskite is investigated, focusing on the acquisition parameters appropriate for energy-dispersive X-ray spectroscopy in a scanning transmission electron microscope (STEM-EDX). The acquisition parameters are systematically varied to examine the relationship between electron dose, data quality, and beam damage. Five metrics are outlined to assess the quality of STEM-EDX data and severity of beam damage, further validated by dark field STEM imaging. Loss of iodine through vacancy creation is found to be the primary manifestation of electron beam damage in the perovskite specimen, and iodine content is seen to decrease exponentially with electron dose. This work demonstrates data acquisition and analysis strategies that can be used for studying electron beam damage and for achieving reliable quantification for a broad range of beam-sensitive materials.
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Affiliation(s)
- Felix Utama Kosasih
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Stefania Cacovich
- CNRS-IPVF, Institut Photovoltaïque d'Ile-de-France, UMR 9006, 18, Boulevard Thomas Gobert, Palaiseau, 91120, France
| | - Giorgio Divitini
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Caterina Ducati
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
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36
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Martinez De La Cruz B, Markus R, Malla S, Haig MI, Gell C, Sang F, Bellows E, Sherif MA, McLean D, Lourdusamy A, Self T, Bodi Z, Smith S, Fay M, Macdonald IA, Fray R, Knight HM. Modifying the m 6A brain methylome by ALKBH5-mediated demethylation: a new contender for synaptic tagging. Mol Psychiatry 2021; 26:7141-7153. [PMID: 34663904 PMCID: PMC8872986 DOI: 10.1038/s41380-021-01282-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/02/2021] [Accepted: 08/25/2021] [Indexed: 02/08/2023]
Abstract
Synaptic plasticity processes, which underlie learning and memory formation, require RNA to be translated local to synapses. The synaptic tagging hypothesis has previously been proposed to explain how mRNAs are available at specific activated synapses. However how RNA is regulated, and which transcripts are silenced or processed as part of the tagging process is still unknown. Modification of RNA by N6-methyladenosine (m6A/m) influences the cellular fate of mRNA. Here, by advanced microscopy, we showed that m6A demethylation by the eraser protein ALKBH5 occurs at active synaptic ribosomes and at synapses during short term plasticity. We demonstrated that at activated glutamatergic post-synaptic sites, both the YTHDF1 and YTHDF3 reader and the ALKBH5 eraser proteins increase in co-localisation to m6A-modified RNAs; but only the readers showed high co-localisation to modified RNAs during late-stage plasticity. The YTHDF1 and YTHFDF3 readers also exhibited differential roles during synaptic maturation suggesting that temporal and subcellular abundance may determine specific function. m6A-sequencing of human parahippocampus brain tissue revealed distinct white and grey matter m6A methylome profiles indicating that cellular context is a fundamental factor dictating regulated pathways. However, in both neuronal and glial cell-rich tissue, m6A effector proteins are themselves modified and m6A epitranscriptional and posttranslational modification processes coregulate protein cascades. We hypothesise that the availability m6A effector protein machinery in conjunction with RNA modification, may be important in the formation of condensed synaptic nanodomain assemblies through liquid-liquid phase separation. Our findings support that m6A demethylation by ALKBH5 is an intrinsic component of the synaptic tagging hypothesis and a molecular switch which leads to alterations in the RNA methylome, synaptic dysfunction and potentially reversible disease states.
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Affiliation(s)
- Braulio Martinez De La Cruz
- grid.4563.40000 0004 1936 8868Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK ,grid.415971.f0000 0004 0605 8588Present Address: MRC Laboratory of Molecular Cell Biology, UCL, London, UK
| | - Robert Markus
- grid.4563.40000 0004 1936 8868School of Life Sciences Imaging Facility, University of Nottingham, Nottingham, UK
| | - Sunir Malla
- grid.4563.40000 0004 1936 8868Deep Seq: Next Generation Sequencing Facility, University of Nottingham, Nottingham, UK
| | - Maria Isabel Haig
- grid.4563.40000 0004 1936 8868Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Chris Gell
- grid.4563.40000 0004 1936 8868School of Life Sciences Imaging Facility, University of Nottingham, Nottingham, UK
| | - Fei Sang
- grid.4563.40000 0004 1936 8868Deep Seq: Next Generation Sequencing Facility, University of Nottingham, Nottingham, UK
| | - Eleanor Bellows
- grid.4563.40000 0004 1936 8868Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Mahmoud Awad Sherif
- grid.4563.40000 0004 1936 8868Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Denise McLean
- grid.4563.40000 0004 1936 8868School of Life Sciences Imaging Facility, University of Nottingham, Nottingham, UK
| | - Anbarasu Lourdusamy
- grid.4563.40000 0004 1936 8868Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Tim Self
- grid.4563.40000 0004 1936 8868School of Life Sciences Imaging Facility, University of Nottingham, Nottingham, UK
| | - Zsuzsanna Bodi
- grid.4563.40000 0004 1936 8868Division of Plant Sciences, School of Biosciences, University of Nottingham, Nottingham, UK
| | - Stuart Smith
- grid.4563.40000 0004 1936 8868Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Michael Fay
- grid.4563.40000 0004 1936 8868Nanoscale and Microscale Research Centre, University of Nottingham, Nottingham, UK
| | - Ian A. Macdonald
- grid.4563.40000 0004 1936 8868Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Rupert Fray
- grid.4563.40000 0004 1936 8868Division of Plant Sciences, School of Biosciences, University of Nottingham, Nottingham, UK
| | - Helen Miranda Knight
- Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK.
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37
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Visualization of chemical bonding in a silica-filled rubber nanocomposite using STEM-EELS. Sci Rep 2020; 10:21558. [PMID: 33299047 PMCID: PMC7725830 DOI: 10.1038/s41598-020-78393-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/19/2020] [Indexed: 12/03/2022] Open
Abstract
In nanocomposites, the adhesion between nanofillers and the polymeric matrix is key to the mechanical properties. The strength and spatial distribution of the adhesive layer around the nanofillers are important, particularly the presence of chemical bonding between the nanofillers and matrix. In this work, we studied a styrene-butadiene rubber composite filled with silica nanoparticles to visualize the spatial distribution of the adhesive layer. A silane coupling agent (SCA) was added to the nanocomposite for strong adhesion. The reaction involving the SCA on the silica surface was investigated by scanning transmission electron microscopy combined with electron energy-loss spectroscopy. Si-L2,3 spectra of the silica-filled rubber nanocomposite without the SCA were the same around the nanofillers, whereas in the nanocomposite containing the SCA the spectra were position-dependent. The spectra were fitted with the intensity profiles of the Si-L2,3 spectra of silica and SCA by multiple linear least-squares fitting. The fitting coefficients of silica and SCA were used to map the spatial distribution of the chemical bonding between silica and rubber chains. Chemical bonding was observed around the silica nanoparticles but not in the SBR matrix region, providing direct evidence of the reinforcing mechanism in the silica-filled rubber nanocomposite.
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38
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Liu H, Grasseschi D, Dodda A, Fujisawa K, Olson D, Kahn E, Zhang F, Zhang T, Lei Y, Branco RBN, Elías AL, Silva RC, Yeh YT, Maroneze CM, Seixas L, Hopkins P, Das S, de Matos CJS, Terrones M. Spontaneous chemical functionalization via coordination of Au single atoms on monolayer MoS 2. SCIENCE ADVANCES 2020; 6:eabc9308. [PMID: 33268357 PMCID: PMC7821882 DOI: 10.1126/sciadv.abc9308] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 10/20/2020] [Indexed: 05/21/2023]
Abstract
Surface functionalization of metallic and semiconducting 2D transition metal dichalcogenides (TMDs) have mostly relied on physi- and chemi-sorption at defect sites, which can diminish the potential applications of the decorated 2D materials, as structural defects can have substantial drawbacks on the electronic and optoelectronic characteristics. Here, we demonstrate a spontaneous defect-free functionalization method consisting of attaching Au single atoms to monolayers of semiconducting MoS2(1H) via S-Au-Cl coordination complexes. This strategy offers an effective and controllable approach for tuning the Fermi level and excitation spectra of MoS2 via p-type doping and enhancing the thermal boundary conductance of monolayer MoS2, thus promoting heat dissipation. The coordination-based method offers an effective and damage-free route of functionalizing TMDs and can be applied to other metals and used in single-atom catalysis, quantum information devices, optoelectronics, and enhanced sensing.
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Affiliation(s)
- He Liu
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Daniel Grasseschi
- MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil.
- Surface Chemistry and Nanomaterials Laboratory, Inorganic Chemistry Department, Chemistry Institute, Federal University of Rio de Janeiro (UFRJ), 21941-909 Rio de Janeiro, Brazil
| | - Akhil Dodda
- Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Kazunori Fujisawa
- Research Initiative for Supra-Materials (RISM), Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA 16802, USA
| | - David Olson
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - Ethan Kahn
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Fu Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Tianyi Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Yu Lei
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | | | - Ana Laura Elías
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Physics, Binghamton University, Binghamton, NY 13902, USA
| | - Rodolfo Cruz Silva
- Research Initiative for Supra-Materials (RISM), Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
- Global Aqua Innovation Center, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 8553, Japan
| | - Yin-Ting Yeh
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA 16802, USA
| | - Camila M Maroneze
- MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil
| | - Leandro Seixas
- MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil
| | - Patrick Hopkins
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904, USA
- Department of Physics, University of Virginia, Charlottesville, VA 22904, USA
| | - Saptarshi Das
- Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Christiano J S de Matos
- MackGraphe-Graphene and Nanomaterials Research Center, Mackenzie Presbyterian University, 01302-907 São Paulo, Brazil
| | - Mauricio Terrones
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA
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39
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De Wael A, De Backer A, Van Aert S. Hidden Markov model for atom-counting from sequential ADF STEM images: Methodology, possibilities and limitations. Ultramicroscopy 2020; 219:113131. [PMID: 33091707 DOI: 10.1016/j.ultramic.2020.113131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 10/23/2022]
Abstract
We present a quantitative method which allows us to reliably measure dynamic changes in the atomic structure of monatomic crystalline nanomaterials from a time series of atomic resolution annular dark field scanning transmission electron microscopy images. The approach is based on the so-called hidden Markov model and estimates the number of atoms in each atomic column of the nanomaterial in each frame of the time series. We discuss the origin of the improved performance for time series atom-counting as compared to the current state-of-the-art atom-counting procedures, and show that the so-called transition probabilities that describe the probability for an atomic column to lose or gain one or more atoms from frame to frame are particularly important. Using these transition probabilities, we show that the method can also be used to estimate the probability and cross section related to structural changes. Furthermore, we explore the possibilities for applying the method to time series recorded under variable environmental conditions. The method is shown to be promising for a reliable quantitative analysis of dynamic processes such as surface diffusion, adatom dynamics, beam effects, or in situ experiments.
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Affiliation(s)
- Annelies De Wael
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Annick De Backer
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Sandra Van Aert
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium.
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40
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Paterson GW, Webster RWH, Ross A, Paton KA, Macgregor TA, McGrouther D, MacLaren I, Nord M. Fast Pixelated Detectors in Scanning Transmission Electron Microscopy. Part II: Post-Acquisition Data Processing, Visualization, and Structural Characterization. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:944-963. [PMID: 32883393 DOI: 10.1017/s1431927620024307] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Fast pixelated detectors incorporating direct electron detection (DED) technology are increasingly being regarded as universal detectors for scanning transmission electron microscopy (STEM), capable of imaging under multiple modes of operation. However, several issues remain around the post-acquisition processing and visualization of the often very large multidimensional STEM datasets produced by them. We discuss these issues and present open source software libraries to enable efficient processing and visualization of such datasets. Throughout, we provide examples of the analysis methodologies presented, utilizing data from a 256 × 256 pixel Medipix3 hybrid DED detector, with a particular focus on the STEM characterization of the structural properties of materials. These include the techniques of virtual detector imaging; higher-order Laue zone analysis; nanobeam electron diffraction; and scanning precession electron diffraction. In the latter, we demonstrate a nanoscale lattice parameter mapping with a fractional precision ≤6 × 10−4 (0.06%).
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Affiliation(s)
- Gary W Paterson
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Robert W H Webster
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Andrew Ross
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Kirsty A Paton
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Thomas A Macgregor
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Damien McGrouther
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Ian MacLaren
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Magnus Nord
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
- EMAT, Department of Physics, University of Antwerp, Antwerp2000, Belgium
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41
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Zhao Y, Zhang J, Cai C, Chen J, Zhao X, Liang C, Liu F, Shi Y, Liu X, Che R. Domino Effect of Thickness Fluctuation on Subband Structure and Electron Transport within Semiconductor Cascade Structures. ACS APPLIED MATERIALS & INTERFACES 2020; 12:41950-41959. [PMID: 32809789 DOI: 10.1021/acsami.0c11216] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Effectively restraining random fluctuation of layer thickness (RFT) during the thin-film epitaxy plays an essential part in improving the quality of low-dimensional materials for device application. While it is already challenging to obtain an ideal growth condition for thickness control, the tangle of RFT with interfacial problems makes it even more difficult to guarantee the properties of heterostructures and the performance of devices. In our research, the RFT of potential barriers and wells within a semiconductor multilayer is demonstrated to correlate with the interfacial grading effect (IFG) and to affect the band offset strongly. Then, the synergetic effect of RFT and IFG that serves as the first domino is shown to impact the subband structure and the electron transport successively. On the basis of an investigation of a quantum cascade structure, statistical results indicate a normal distribution of RFT with a standard deviation of about 1 Å and an extreme value of 3 Å (about one monolayer) for all the layers within 38 cascade periods. The "seemingly negligible" RFT could actually reduce the conduction band offset for tens to hundreds of meV and alter the subband gaps at a rate of 40 meV/monolayer at most. Furthermore, the dependence of different subband gaps on the barrier/well thickness differs from one another. In addition, the distribution of wave function could also be regulated dramatically by RFT to change the type of electron transition and thus the carrier lifetime. Further impacts of RFT and the RFT-modulated subband alignment on electron transport result in two different mechanisms (injection-dominant and extraction-dominant) of electron population inversion (PI), which is manifested by comparatively discussing the results of in situ electron holography and macro performances.
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Affiliation(s)
- Yunhao Zhao
- Laboratory of Advanced Materials, Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200438, P. R. China
| | - Jinchuan Zhang
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Beijing 100083, P. R. China
| | - Chenyuan Cai
- Laboratory of Advanced Materials, Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200438, P. R. China
| | - Jie Chen
- Laboratory of Advanced Materials, Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200438, P. R. China
| | - Xuebing Zhao
- Laboratory of Advanced Materials, Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200438, P. R. China
| | - Chongyun Liang
- Department of Chemistry, Fudan University, Shanghai 200433, P. R. China
| | - Fengqi Liu
- Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Beijing 100083, P. R. China
| | - Yi Shi
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Xianhu Liu
- Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education, Zhengzhou 450002, P. R. China
| | - Renchao Che
- Laboratory of Advanced Materials, Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai 200438, P. R. China
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42
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Nord M, Webster RWH, Paton KA, McVitie S, McGrouther D, MacLaren I, Paterson GW. Fast Pixelated Detectors in Scanning Transmission Electron Microscopy. Part I: Data Acquisition, Live Processing, and Storage. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:653-666. [PMID: 32627727 DOI: 10.1017/s1431927620001713] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The use of fast pixelated detectors and direct electron detection technology is revolutionizing many aspects of scanning transmission electron microscopy (STEM). The widespread adoption of these new technologies is impeded by the technical challenges associated with them. These include issues related to hardware control, and the acquisition, real-time processing and visualization, and storage of data from such detectors. We discuss these problems and present software solutions for them, with a view to making the benefits of new detectors in the context of STEM more accessible. Throughout, we provide examples of the application of the technologies presented, using data from a Medipix3 direct electron detector. Most of our software are available under an open source licence, permitting transparency of the implemented algorithms, and allowing the community to freely use and further improve upon them.
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Affiliation(s)
- Magnus Nord
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
- EMAT, Department of Physics, University of Antwerp, Antwerp2000, Belgium
| | - Robert W H Webster
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Kirsty A Paton
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Stephen McVitie
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Damien McGrouther
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Ian MacLaren
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
| | - Gary W Paterson
- SUPA, School of Physics and Astronomy, University of Glasgow, GlasgowG12 8QQ, UK
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43
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Voronkova VI, Antipin AM, Sorokin TA, Novikova NE, Kharitonova EP, Orlova EI, Kvartalov VB, Presniakov MY, Bondarenko VI, Vasiliev AL, Sorokina NI. Synthesis, structure and properties of layered Pr 2MoO 6-based oxymolybdates doped with Mg. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2020; 76:492-501. [PMID: 32831266 DOI: 10.1107/s2052520620005740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/25/2020] [Indexed: 06/11/2023]
Abstract
Undoped and Mg-doped Pr2MoO6 oxymolybdate polycrystals and single crystals have been prepared by solid-state reactions and flux growth. The compounds have been characterized by powder X-ray diffraction, energy-dispersive spectroscopy, inductively coupled plasma mass spectrometry, scanning transmission electron microscopy, single crystal X-ray structure analysis, differential scanning calorimetry and thermogravimetry. The (MgO)x(Pr2O3)y(MoO3)z (x + y + z = 1) solid solution series has been shown to extend to x = 0.03. The structure of the Mg-doped Pr2MoO6 single crystals can be represented as superimposed lattices of the main matrix (Pr2MoO6) and lattices in which Mo atoms are partially replaced by Mg. The incorporation of Mg atoms into the structure of Pr2MoO6 results in the disordering of the praseodymium and oxygen lattices. Both the polycrystalline and single-crystal Mg-doped samples are hygroscopic.
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Affiliation(s)
- Valentina I Voronkova
- Faculty of Physics, Lomonosov Moscow State University, GSP-1, Leninskiye Gory1-2, Moscow, 119991, Russian Federation
| | - Alexander M Antipin
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre 'Crystallography and Photonics' of Russian Academy of Sciences, Leninskii Prospekt 59, Moscow, 119333, Russian Federation
| | - Timofei A Sorokin
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre 'Crystallography and Photonics' of Russian Academy of Sciences, Leninskii Prospekt 59, Moscow, 119333, Russian Federation
| | - Nataliya E Novikova
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre 'Crystallography and Photonics' of Russian Academy of Sciences, Leninskii Prospekt 59, Moscow, 119333, Russian Federation
| | - Elena P Kharitonova
- Faculty of Physics, Lomonosov Moscow State University, GSP-1, Leninskiye Gory1-2, Moscow, 119991, Russian Federation
| | - Ekaterina I Orlova
- Faculty of Physics, Lomonosov Moscow State University, GSP-1, Leninskiye Gory1-2, Moscow, 119991, Russian Federation
| | - Vladimir B Kvartalov
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre 'Crystallography and Photonics' of Russian Academy of Sciences, Leninskii Prospekt 59, Moscow, 119333, Russian Federation
| | - Mikhail Yu Presniakov
- National Research Center 'Kurchatov Institute', Akademika Kurchatova pl., 1, Moscow, 123182, Russian Federation
| | - Vladimir I Bondarenko
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre 'Crystallography and Photonics' of Russian Academy of Sciences, Leninskii Prospekt 59, Moscow, 119333, Russian Federation
| | - Alexander L Vasiliev
- National Research Center 'Kurchatov Institute', Akademika Kurchatova pl., 1, Moscow, 123182, Russian Federation
| | - Nataliya I Sorokina
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre 'Crystallography and Photonics' of Russian Academy of Sciences, Leninskii Prospekt 59, Moscow, 119333, Russian Federation
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44
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Ede JM, Beanland R. Partial Scanning Transmission Electron Microscopy with Deep Learning. Sci Rep 2020; 10:8332. [PMID: 32433582 PMCID: PMC7239858 DOI: 10.1038/s41598-020-65261-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/28/2020] [Indexed: 11/09/2022] Open
Abstract
Compressed sensing algorithms are used to decrease electron microscope scan time and electron beam exposure with minimal information loss. Following successful applications of deep learning to compressed sensing, we have developed a two-stage multiscale generative adversarial neural network to complete realistic 512 × 512 scanning transmission electron micrographs from spiral, jittered gridlike, and other partial scans. For spiral scans and mean squared error based pre-training, this enables electron beam coverage to be decreased by 17.9× with a 3.8% test set root mean squared intensity error, and by 87.0× with a 6.2% error. Our generator networks are trained on partial scans created from a new dataset of 16227 scanning transmission electron micrographs. High performance is achieved with adaptive learning rate clipping of loss spikes and an auxiliary trainer network. Our source code, new dataset, and pre-trained models are publicly available.
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Affiliation(s)
- Jeffrey M Ede
- University of Warwick, Department of Physics, Coventry, CV4 7AL, UK.
| | - Richard Beanland
- University of Warwick, Department of Physics, Coventry, CV4 7AL, UK
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45
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A hydrodynamic approach to electron beam imaging using a Bloch wave representation. Ultramicroscopy 2020; 212:112979. [DOI: 10.1016/j.ultramic.2020.112979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/02/2020] [Accepted: 03/15/2020] [Indexed: 11/24/2022]
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46
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Zhang T, Fujisawa K, Zhang F, Liu M, Lucking MC, Gontijo RN, Lei Y, Liu H, Crust K, Granzier-Nakajima T, Terrones H, Elías AL, Terrones M. Universal In Situ Substitutional Doping of Transition Metal Dichalcogenides by Liquid-Phase Precursor-Assisted Synthesis. ACS NANO 2020; 14:4326-4335. [PMID: 32208674 DOI: 10.1021/acsnano.9b09857] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Doping lies at the heart of modern semiconductor technologies. Therefore, for two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs), the significance of controlled doping is no exception. Recent studies have indicated that, by substitutionally doping 2D TMDs with a judicious selection of dopants, their electrical, optical, magnetic, and catalytic properties can be effectively tuned, endowing them with great potential for various practical applications. Herein, and inspired by the sol-gel process, we report a liquid-phase precursor-assisted approach for in situ substitutional doping of monolayered TMDs and their in-plane heterostructures with tunable doping concentration. This highly reproducible route is based on the high-temperature chalcogenation of spin-coated aqueous solutions containing host and dopant precursors. The precursors are mixed homogeneously at the atomic level in the liquid phase prior to the synthesis process, thus allowing for an improved doping uniformity and controllability. We further demonstrate the incorporation of various transition metal atoms, such as iron (Fe), rhenium (Re), and vanadium (V), into the lattice of TMD monolayers to form Fe-doped WS2, Re-doped MoS2, and more complex material systems such as V-doped in-plane WxMo1-xS2-MoxW1-xS2 heterostructures, among others. We envisage that our developed approach is universal and could be extended to incorporate a variety of other elements into 2D TMDs and create in-plane heterointerfaces in a single step, which may enable applications such as electronics and spintronics at the 2D limit.
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Affiliation(s)
- Tianyi Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Kazunori Fujisawa
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Research Initiative for Supra-Materials, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
| | - Fu Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mingzu Liu
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Michael C Lucking
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Rafael Nunes Gontijo
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yu Lei
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - He Liu
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Kevin Crust
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tomotaroh Granzier-Nakajima
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Humberto Terrones
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Ana Laura Elías
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mauricio Terrones
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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47
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Luo R, Xu WW, Zhang Y, Wang Z, Wang X, Gao Y, Liu P, Chen M. Van der Waals interfacial reconstruction in monolayer transition-metal dichalcogenides and gold heterojunctions. Nat Commun 2020; 11:1011. [PMID: 32081885 PMCID: PMC7035323 DOI: 10.1038/s41467-020-14753-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/29/2020] [Indexed: 11/09/2022] Open
Abstract
The structures and properties of van der Waals (vdW) heterojunctions between semiconducting two-dimensional transition-metal dichalcogenides (2D TMDs) and conductive metals, such as gold, significantly influence the performances of 2D-TMD based electronic devices. Chemical vapor deposition is one of the most promising approaches for large-scale synthesis and fabrication of 2D TMD electronics with naturally formed TMD/metal vdW interfaces. However, the structure and chemistry of the vdW interfaces are less known. Here we report the interfacial reconstruction between TMD monolayers and gold substrates. The participation of sulfur leads to the reconstruction of Au {001} surface with the formation of a metastable Au4S4 interfacial phase which is stabilized by the top MoS2 and WS2 monolayers. Moreover, the enhanced vdW interaction between the reconstructed Au4S4 interfacial phase and TMD monolayers results in the transition from n-type TMD-Au Schottky contact to p-type one with reduced energy barrier height.
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Affiliation(s)
- Ruichun Luo
- Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Wen Wu Xu
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, P. R. China
| | - Yongzheng Zhang
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Ziqian Wang
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Xiaodong Wang
- Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Yi Gao
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, P. R. China
| | - Pan Liu
- Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.
| | - Mingwei Chen
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA.
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.
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48
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Aarholt T, Frodason YK, Prytz Ø. Imaging defect complexes in scanning transmission electron microscopy: Impact of depth, structural relaxation, and temperature investigated by simulations. Ultramicroscopy 2019; 209:112884. [PMID: 31756598 DOI: 10.1016/j.ultramic.2019.112884] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 10/25/2019] [Accepted: 11/01/2019] [Indexed: 10/25/2022]
Affiliation(s)
- Thomas Aarholt
- Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, P. O. Box 1048, Blindern, N-0316 Oslo, Norway.
| | - Ymir K Frodason
- Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, P. O. Box 1048, Blindern, N-0316 Oslo, Norway
| | - Øystein Prytz
- Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, P. O. Box 1048, Blindern, N-0316 Oslo, Norway
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49
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Atomic-scale imaging of the defect dynamics in ceria nanowires under heating by in situ aberration-corrected TEM. Sci China Chem 2019. [DOI: 10.1007/s11426-019-9624-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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50
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Rudinsky S, Sanz AS, Gauvin R. Wave-packet numerical investigation of thermal diffuse scattering: A time-dependent quantum approach to electron diffraction simulations. Micron 2019; 126:102737. [PMID: 31577974 DOI: 10.1016/j.micron.2019.102737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/21/2019] [Accepted: 08/21/2019] [Indexed: 11/19/2022]
Abstract
The effects of thermal diffuse scattering on diffraction of highly-accelerated electrons by crystal lattices are investigated with a method that combines the frozen phonon approximation with an exact numerical solution of the time-dependent Schrödinger equation. The phonon configuration for each single-electron diffraction process is determined by means of Einstein's model. It is shown that this procedure provides the possibility of describing and explaining, in a natural way, after averaging over a number of electron realizations, how the typical diffraction features that characterize a fully coherent pattern are gradually suppressed by thermally-induced incoherence. This is achieved by a controlled increase of the lattice atomic vibrations and is in contrast to the use of attenuating Debye-Waller factors and complex potential absorbers. A lattice with reduced dimensionality is first considered as a working model, where the method renders results compatible with those reported in the literature. Subsequently, a full three-dimensional system is simulated and results are compared to experimental imaging displaying the method's reliability.
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Affiliation(s)
- Samantha Rudinsky
- Department of Mining and Materials Engineering, McGill University, 3610 University, Montreal, Qc., Canada H3A 0C5
| | - Angel S Sanz
- Department of Optics, Faculty of Physical Sciences, Universidad Complutense de Madrid, Pza. Ciencias 1, Ciudad Universitaria 28040, Madrid, Spain
| | - Raynald Gauvin
- Department of Mining and Materials Engineering, McGill University, 3610 University, Montreal, Qc., Canada H3A 0C5.
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