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Urbieta M, Barbry M, Koval P, Rivacoba A, Sánchez-Portal D, Aizpurua J, Zabala N. Footprints of atomic-scale features in plasmonic nanoparticles as revealed by electron energy loss spectroscopy. Phys Chem Chem Phys 2024. [PMID: 38741574 DOI: 10.1039/d4cp01034e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
We present a first-principles theoretical study of the atomistic footprints in the valence electron energy loss spectroscopy (EELS) of nanometer-size metallic particles. Charge density maps of excited plasmons and EEL spectra for specific electron paths through a nanoparticle (Na380 atom cluster) are modeled using ab initio calculations within time-dependent density functional theory. Our findings unveil the atomic-scale sensitivity of EELS within this low-energy spectral range. Whereas localized surface plasmons (LSPs) are particularly sensitive to the atomistic structure of the surface probed by the electron beam, confined bulk plasmons (CBPs) reveal quantum size effects within the nanoparticle's volume. Moreover, we prove that classical local dielectric theories mimicking the atomistic structure of the nanoparticles reproduce the LSP trends observed in quantum calculations, but fall short in describing the CBP behavior observed under different electron trajectories.
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Affiliation(s)
- Mattin Urbieta
- Matematika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola (Eibarko Atala), University of the Basque Country UPV/EHU, 20018 Eibar, Spain.
- Centro de Física de Materiales CSIC - UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
| | - Marc Barbry
- Centro de Física de Materiales CSIC - UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
| | - Peter Koval
- Simune Atomistics S.L., Avenida de Tolosa 76, Donostia-San Sebastian 20018, Spain
| | - Alberto Rivacoba
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
| | - Daniel Sánchez-Portal
- Centro de Física de Materiales CSIC - UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
| | - Javier Aizpurua
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Department of Electricity and Electronics, FCT-ZTF, University of the Basque Country (UPV/EHU), Barrio Sarriena z/g, Leioa, Bizkaia 48940, Spain.
- Ikerbasque, Basque Foundation for Science, Bilbao, Bizkaia 48011, Spain
| | - Nerea Zabala
- Centro de Física de Materiales CSIC - UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastian, Gipuzkoa 20018, Spain
- Department of Electricity and Electronics, FCT-ZTF, University of the Basque Country (UPV/EHU), Barrio Sarriena z/g, Leioa, Bizkaia 48940, Spain.
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Lawrence RA, Ramasse QM, Holsgrove KM, Sando D, Cazorla C, Valanoor N, Arredondo MA. Effects of Multiple Local Environments on Electron Energy Loss Spectra of Epitaxial Perovskite Interfaces. J Phys Chem C Nanomater Interfaces 2022; 126:21453-21466. [PMID: 36582487 PMCID: PMC9791663 DOI: 10.1021/acs.jpcc.2c06879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/15/2022] [Indexed: 06/17/2023]
Abstract
The role of local chemical environments in the electron energy loss spectra of complex multiferroic oxides was studied using computational and experimental techniques. The evolution of the O K-edge across an interface between bismuth ferrite (BFO) and lanthanum strontium manganate (LSMO) was considered through spectral averaging over crystallographically equivalent positions to capture the periodicity of the local O environments. Computational techniques were used to investigate the contribution of individual atomic environments to the overall spectrum, and the role of doping and strain was considered. Chemical variation, even at the low level, was found to have a major impact on the spectral features, whereas strain only induced a small chemical shift to the edge onset energy. Through a combination of these methods, it was possible to explain experimentally observed effects such as spectral flattening near the interface as the combination of spectral responses from multiple local atomic environments.
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Affiliation(s)
- Robert A. Lawrence
- Department
of Physics, University of York, Heslington, North YorkshireYO10 5DD, United Kingdom
| | - Quentin M. Ramasse
- SuperSTEM
Laboratory, SciTech Daresbury Campus, DaresburyWA4 4AD, United Kingdom
- School
of Chemical and Process Engineering and School of Physics and Astronomy, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - Kristina M. Holsgrove
- School
of Mathematics and Physics, Queen’s
University Belfast, BelfastBT7 1NN, Northern Ireland, United Kingdom
| | - Daniel Sando
- School
of Physical and Chemical Sciences, University
of Canterbury, ChristChurch8140, New Zealand
| | - Claudio Cazorla
- Departament
de Fisica, Universitat Politecnica de Catalunya, BarcelonaE-08034, Catalonia, Spain
| | - Nagarajan Valanoor
- School
of Materials Science and Engineering, University
of New South Wales, Sydney, NSW2052, Australia
| | - Miryam A. Arredondo
- School
of Mathematics and Physics, Queen’s
University Belfast, BelfastBT7 1NN, Northern Ireland, United Kingdom
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Ophus C, Zeltmann SE, Bruefach A, Rakowski A, Savitzky BH, Minor AM, Scott MC. Automated Crystal Orientation Mapping in py4DSTEM using Sparse Correlation Matching. Microsc Microanal 2022; 28:1-14. [PMID: 35135651 DOI: 10.1017/s1431927622000101] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Crystalline materials used in technological applications are often complex assemblies composed of multiple phases and differently oriented grains. Robust identification of the phases and orientation relationships from these samples is crucial, but the information extracted from the diffraction condition probed by an electron beam is often incomplete. We have developed an automated crystal orientation mapping (ACOM) procedure which uses a converged electron probe to collect diffraction patterns from multiple locations across a complex sample. We provide an algorithm to determine the orientation of each diffraction pattern based on a fast sparse correlation method. We demonstrate the speed and accuracy of our method by indexing diffraction patterns generated using both kinematical and dynamical simulations. We have also measured orientation maps from an experimental dataset consisting of a complex polycrystalline twisted helical AuAgPd nanowire. From these maps we identify twin planes between adjacent grains, which may be responsible for the twisted helical structure. All of our methods are made freely available as open source code, including tutorials which can be easily adapted to perform ACOM measurements on diffraction pattern datasets.
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Affiliation(s)
- Colin Ophus
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Steven E Zeltmann
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Alexandra Bruefach
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Alexander Rakowski
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Benjamin H Savitzky
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
| | - Andrew M Minor
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
| | - Mary C Scott
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA94720, USA
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Dyck O, Swett JL, Lupini AR, Mol JA, Jesse S. Imaging Secondary Electron Emission from a Single Atomic Layer. Small Methods 2021; 5:e2000950. [PMID: 34927845 DOI: 10.1002/smtd.202000950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/17/2020] [Indexed: 06/14/2023]
Abstract
Graphene-based devices hold promise for a wide range of technological applications. Yet characterizing the structure and the electrical properties of a material that is only one atomic layer thick still poses technical challenges. Recent investigations indicate that secondary-electron electron-beam-induced current (SE-EBIC) imaging can reveal subtle details regarding electrical conductivity and electron transport with high spatial resolution. Here, it is shown that the SEEBIC imaging mode can be used to detect suspended single layers of graphene and distinguish between different numbers of layers. Pristine and contaminated areas of graphene are also compared to show that pristine graphene exhibits a substantially lower SE yield than contaminated regions. This SEEBIC imaging mode may provide valuable information for the engineering of surface coatings where SE yield is a priority.
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Affiliation(s)
- Ondrej Dyck
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Jacob L Swett
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
| | - Andrew R Lupini
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Jan A Mol
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
- School of Physics and Astronomy, Queen Mary University of London, London, E1 4NS, UK
| | - Stephen Jesse
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
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Abstract
Abstract
Deep learning is transforming most areas of science and technology, including electron microscopy. This review paper offers a practical perspective aimed at developers with limited familiarity. For context, we review popular applications of deep learning in electron microscopy. Following, we discuss hardware and software needed to get started with deep learning and interface with electron microscopes. We then review neural network components, popular architectures, and their optimization. Finally, we discuss future directions of deep learning in electron microscopy.
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Abstract
Over the past decade, III-V heterostructure nanowires have attracted a surge of attention for their application in novel semiconductor devices such as tunneling field-effect transistors (TFETs). The functionality of such devices critically depends on the specific atomic arrangement at the semiconductor heterointerfaces. However, most of the currently available characterization techniques lack sufficient spatial resolution to provide local information on the atomic structure and composition of these interfaces. Atomic-resolution spectrum imaging by means of electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) is a powerful technique with the potential to resolve structure and chemical composition with sub-angstrom spatial resolution and to provide localized information about the physical properties of the material at the atomic scale. Here, we demonstrate the use of atomic-resolution EELS to understand the interface atomic arrangement in three-dimensional heterostructures in semiconductor nanowires. We observed that the radial interfaces of GaSb-InAs heterostructure nanowires are atomically abrupt, while the axial interface in contrast consists of an interfacial region where intermixing of the two compounds occurs over an extended spatial region. The local atomic configuration affects the band alignment at the interface and, hence, the charge transport properties of devices such as GaSb-InAs nanowire TFETs. STEM-EELS thus represents a very promising technique for understanding nanowire physical properties, such as differing electrical behavior across the radial and axial heterointerfaces of GaSb-InAs nanowires for TFET applications.
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Affiliation(s)
- Reza R Zamani
- Solid-State Physics , Lund University , Box 118, Lund 22100 , Sweden
| | - Fredrik S Hage
- SuperSTEM Laboratory, SciTech Daresbury Campus , Keckwick Lane , Warrington WA4 4AD , United Kingdom
| | - Sebastian Lehmann
- Solid-State Physics , Lund University , Box 118, Lund 22100 , Sweden
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus , Keckwick Lane , Warrington WA4 4AD , United Kingdom
| | - Kimberly A Dick
- Solid-State Physics , Lund University , Box 118, Lund 22100 , Sweden
- Centre for Analysis and Synthesis , Lund University , Box 124, Lund 22100 , Sweden
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Hage FS, Hardcastle TP, Gjerding MN, Kepaptsoglou DM, Seabourne CR, Winther KT, Zan R, Amani JA, Hofsaess HC, Bangert U, Thygesen KS, Ramasse QM. Local Plasmon Engineering in Doped Graphene. ACS Nano 2018; 12:1837-1848. [PMID: 29369611 DOI: 10.1021/acsnano.7b08650] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Single-atom B or N substitutional doping in single-layer suspended graphene, realized by low-energy ion implantation, is shown to induce a dampening or enhancement of the characteristic interband π plasmon of graphene through a high-resolution electron energy loss spectroscopy study using scanning transmission electron microscopy. A relative 16% decrease or 20% increase in the π plasmon quality factor is attributed to the presence of a single substitutional B or N atom dopant, respectively. This modification is in both cases shown to be relatively localized, with data suggesting the plasmonic response tailoring can no longer be detected within experimental uncertainties beyond a distance of approximately 1 nm from the dopant. Ab initio calculations confirm the trends observed experimentally. Our results directly confirm the possibility of tailoring the plasmonic properties of graphene in the ultraviolet waveband at the atomic scale, a crucial step in the quest for utilizing graphene's properties toward the development of plasmonic and optoelectronic devices operating at ultraviolet frequencies.
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Affiliation(s)
| | - Trevor P Hardcastle
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - Morten N Gjerding
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Demie M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- York NanoCentre, University of York , Heslington, York YO10 5BR, U.K
| | - Che R Seabourne
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - Kirsten T Winther
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Recep Zan
- Nanotechnology Application and Research Center, Niğde Omer Halisdemir University , Niğde 51000, Turkey
| | - Julian Alexander Amani
- II Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Hans C Hofsaess
- II Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Ursel Bangert
- Bernal Institute and Department of Physics, University of Limerick , Limerick, Ireland
| | - Kristian S Thygesen
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
- School of Physics, University of Leeds , Leeds LS2 9JT, U.K
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Lord AM, Ramasse QM, Kepaptsoglou DM, Periwal P, Ross FM, Wilks SP. Stability of Schottky and Ohmic Au Nanocatalysts to ZnO Nanowires. Nano Lett 2017; 17:6626-6636. [PMID: 29024594 DOI: 10.1021/acs.nanolett.7b02561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Manufacturable nanodevices must now be the predominant goal of nanotechnological research to ensure the enhanced properties of nanomaterials can be fully exploited and fulfill the promise that fundamental science has exposed. Here, we test the electrical stability of Au nanocatalyst-ZnO nanowire contacts to determine the limits of the electrical transport properties and the metal-semiconductor interfaces. While the transport properties of as-grown Au nanocatalyst contacts to ZnO nanowires have been well-defined, the stability of the interfaces over lengthy time periods and the electrical limits of the ohmic or Schottky function have not been studied. In this work, we use a recently developed iterative analytical process that directly correlates multiprobe transport measurements with subsequent aberration-corrected scanning transmission electron microscopy to study the electrical, structural, and chemical properties when the nanowires are pushed to their electrical limits and show structural changes occur at the metal-nanowire interface or at the nanowire midshaft. The ohmic contacts exhibit enhanced quantum-mechanical edge-tunneling transport behavior because of additional native semiconductor material at the contact edge due to a strong metal-support interaction. The low-resistance nature of the ohmic contacts leads to catastrophic breakdown at the middle of the nanowire span where the maximum heating effect occurs. Schottky-type Au-nanowire contacts are observed when the nanowires are in the as-grown pristine state and display entirely different breakdown characteristics. The higher-resistance rectifying I-V behavior degrades as the current is increased which leads to a permanent weakening of the rectifying effect and atomic-scale structural changes at the edge of the Au interface where the tunneling current is concentrated. Furthermore, to study modified nanowires such as might be used in devices the nanoscale tunneling path at the interface edge of the ohmic nanowire contacts is removed with a simple etch treatment and the nanowires show similar I-V characteristics during breakdown as the Schottky pristine contacts. Breakdown is shown to occur either at the nanowire midshaft or at the Au contact depending on the initial conductivity of the Au contact interface. These results demonstrate the Au-nanowire structures are capable of withstanding long periods of electrical stress and are stable at high current densities ensuring they are ideal components for nanowire-device designs while providing the flexibility of choosing the electrical transport properties which other Au-nanowire systems cannot presently deliver.
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Affiliation(s)
- Alex M Lord
- Centre for NanoHealth, College of Engineering, University of Swansea , Singleton Park SA2 8PP, United Kingdom
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Keckwick Lane, Daresbury WA4 4AD, United Kingdom
| | - Despoina M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Keckwick Lane, Daresbury WA4 4AD, United Kingdom
| | - Priyanka Periwal
- Department of Electrical Engineering, University of Cambridge , Cambridge CB0 3FA, United Kingdom
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, United States of America
| | - Frances M Ross
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, United States of America
| | - Steve P Wilks
- Multidisciplinary Nanotechnology Centre, Department of Physics, College of Science, University of Swansea , Singleton Park, SA2 8PP, United Kingdom
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