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Differential electron yield imaging with STXM Ultramicroscopy (IF 2.452) Pub Date : 2020-12-30 William A. Hubbard; Jared J. Lodico; Xin Yi Ling; Brian T. Zutter; Young-Sang Yu; David A. Shapiro; B.C. Regan
Total electron yield (TEY) imaging is an established scanning transmission X-ray microscopy (STXM) technique that gives varying contrast based on a sample’s geometry, elemental composition, and electrical conductivity. However, the TEY-STXM signal is determined solely by the electrons that the beam ejects from the sample. A related technique, X-ray beam-induced current (XBIC) imaging, is sensitive
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Sample Preparation Methods for Optimal HS-AFM Analysis: Duplex Stainless Steel Ultramicroscopy (IF 2.452) Pub Date : 2021-01-16 Stacy Moore; Alexander D. Warren; Robert Burrows; Oliver D. Payton; Loren Picco; Freddie S. Russell-Pavier; Peter G. Martin; Tomas L. Martin
The contact mode high-speed atomic force microscope (AFM) operates orders of magnitude faster than conventional AFMs. It is capable of capturing multiple frames per second with nanometre-scale lateral resolution and subatomic height resolution. This advancement in imaging rate allows for microscale analysis across macroscale surfaces, making it suitable for applications across materials science. However
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Evaluation of microstructure and conductivity of two-phase materials by the scanning spreading resistance microscopy (the case of shungite) Ultramicroscopy (IF 2.452) Pub Date : 2021-01-16 I.V. Antonets; Ye.A. Golubev; V.I. Shcheglov
The determination of the content of the conducting phase and the assessment of conductivity by microscopic images are interesting for rapid and non-destructive analysis of the electrophysical properties of two-phase (conductor/dielectric) samples during the atomic force microscopy. In this paper we summarized results of the analysis of the conductivity maps of the shungite surface by the method of
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High-precision orientation mapping from spherical harmonic transform indexing of electron backscatter diffraction patterns Ultramicroscopy (IF 2.452) Pub Date : 2020-12-17 Gregory Sparks; Paul A. Shade; Michael D. Uchic; Stephen R. Niezgoda; Michael J. Mills; Mark Obstalecki
The angular precision of crystal orientation determination by cross-correlating dynamically simulated electron diffraction patterns with experimental patterns via spherical harmonic analysis is investigated. The best precision found in this study is 0.016°, which approaches the level reported in the literature for other high-precision electron backscatter diffraction implementations. At this angular
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Principal image decomposition for multi-detector backscatter electron topography reconstruction Ultramicroscopy (IF 2.452) Pub Date : 2021-01-15 Jan Neggers; Eva Héripré; Marc Bonnet; Denis Boivin; Alexandre Tanguy; Simon Hallais; Fabrice Gaslain; Elodie Rouesne; Stéphane Roux
Scanning Electron Microscopes (SEMs) often generate images with a shaded appearance which gives a natural 3D impression. Ergo, quite a few methods to reconstruct the 3D surface topography from these using shape-from-shading methods are available in the literature. Here, a novel approach is discussed which uses BackScatter Electron (BSE) images from multiple detectors to reconstruct the topography.
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Charting the low-loss region in electron energy loss spectroscopy with machine learning Ultramicroscopy (IF 2.452) Pub Date : 2021-01-09 Laurien I. Roest; Sabrya E. van Heijst; Louis Maduro; Juan Rojo; Sonia Conesa-Boj
Exploiting the information provided by electron energy-loss spectroscopy (EELS) requires reliable access to the low-loss region where the zero-loss peak (ZLP) often overwhelms the contributions associated to inelastic scatterings off the specimen. Here we deploy machine learning techniques developed in particle physics to realise a model-independent, multidimensional determination of the ZLP with a
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Complementary LEEM and eV-TEM for imaging and spectroscopy Ultramicroscopy (IF 2.452) Pub Date : 2021-01-07 Peter S. Neu; Daniël Geelen; Aniket Thete; Rudolf M. Tromp; Sense Jan van der Molen
Transmission electron microscopy at very low energy is a promising way to avoid damaging delicate biological samples with the incident electrons, a known problem in conventional transmission electron microscopy. For imaging in the 0-30 eV range, we added a second electron source to a low energy electron microscopy (LEEM) setup, enabling imaging and spectroscopy in both transmission and reflection mode
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Time-resolved compositional mapping during in situ TEM studies Ultramicroscopy (IF 2.452) Pub Date : 2021-01-01 Axel R. Persson; Marcus Tornberg; Robin Sjökvist; Daniel Jacobsson
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Angle-resolved STEM using an iris aperture: Scattering contributions and sources of error for the quantitative analysis in Si Ultramicroscopy (IF 2.452) Pub Date : 2020-11-18 Tim Grieb; Florian F. Krause; Knut Müller-Caspary; Saleh Firoozabadi; Christoph Mahr; Marco Schowalter; Andreas Beyer; Oliver Oppermann; Kerstin Volz; Andreas Rosenauer
The angle-resolved electron scattering is investigated in scanning-transmission electron microscopy (STEM) using a motorised iris aperture placed above a conventional annular detector. The electron intensity scattered into various angle ranges is compared with simulations that were carried out in the frozen-lattice approximation. As figure of merit for the agreement of experiment and simulation we
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Contrast transfer and noise considerations in focused-probe electron ptychography Ultramicroscopy (IF 2.452) Pub Date : 2020-12-17 Colum M. O’Leary; Gerardo T. Martinez; Emanuela Liberti; Martin J. Humphry; Angus I. Kirkland; Peter D. Nellist
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Robust scan synchronized force-fluorescence imaging Ultramicroscopy (IF 2.452) Pub Date : 2020-11-15 Patrick Schmidt; John Lajoie; Sanjeevi Sivasankar
Simultaneous atomic force microscope (AFM) and sample scanning confocal fluorescence microscope measurements are widely used to obtain mechanistic and structural insights into protein dynamics in live cells. However, the absence of a robust technique to synchronously scan both AFM and confocal microscope piezo stages makes it difficult to visualize force-induced changes in fluorescent protein distribution
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A simple method to clean ligand contamination on TEM grids Ultramicroscopy (IF 2.452) Pub Date : 2020-12-15 Chen Li; Adrian Pedrazo Tardajos; Da Wang; Daniel Choukroun; Kevin Van Daele; Tom Breugelmans; Sara Bals
Colloidal nanoparticles (NPs) including nanowires and nanosheets made by chemical methods involve many organic ligands. When the structure of NPs is investigated via transmission electron microscopy (TEM), the organic ligands act as a source for e-beam induced deposition and this causes substantial build-up of carbon layers in the investigated areas, which is typically referred to as “contamination”
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Accurate measurement of strain at interfaces in 4D-STEM: A comparison of various methods Ultramicroscopy (IF 2.452) Pub Date : 2020-12-14 Christoph Mahr; Knut Müller-Caspary; Tim Grieb; Florian F. Krause; Marco Schowalter; Andreas Rosenauer
Strain analysis by nano-beam electron diffraction allows for measurements of strain with nanometre resolution in a large field of view. This is done by evaluating distances between diffraction discs in diffraction patterns acquired while a focussed electron beam is scanned across the sample in a transmission electron microscope. The bottleneck of this method is a precise determination of diffraction
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Integrated correction of optical distortions for global HR-EBSD techniques Ultramicroscopy (IF 2.452) Pub Date : 2020-10-29 Clément Ernould; Benoît Beausir; Jean-Jacques Fundenberger; Vincent Taupin; Emmanuel Bouzy
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Support vector machine for EELS oxidation state determination Ultramicroscopy (IF 2.452) Pub Date : 2020-12-07 D. del-Pozo-Bueno; F. Peiró; S. Estradé
Electron Energy-Loss Spectroscopy (EELS) is a powerful and versatile spectroscopic technique used to study the composition and local optoelectronic properties of nanometric materials. Currently, this technique is generating large amounts of spectra per experiment, producing a huge quantity of data to analyse. Several strategies can be applied in order to classify these data to map physical properties
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Active calibration reference of minimized height for characterization of scanning thermal microscopy systems Ultramicroscopy (IF 2.452) Pub Date : 2020-12-02 Paweł Janus; Dariusz Szmigiel; Andrzej Sierakowski; Maciej Rudek; Teodor Gotszalk
In this paper we describe the design, technology and application of a test and reference sample for calibration and characterization of scanning thermal microscopy (SThM) probes and systems. In our solution temperature field in thin film structure, which is being contacted with the thermal tip is controlled in the traceable manner. The developed technology, integrating plasma etching of Pt and chemical-mechanical
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Fast versus conventional HAADF-STEM tomography of nanoparticles: advantages and challenges Ultramicroscopy (IF 2.452) Pub Date : 2020-12-08 Hans Vanrompay; Alexander Skorikov; Eva Bladt; Armand Béché; Bert Freitag; Johan Verbeeck; Sara Bals
HAADF-STEM tomography is a widely used experimental technique for analyzing nanometer-scale structures of a large variety of materials in three dimensions. It is especially useful for studying crystalline nanoparticles, where conventional TEM tomography suffers from diffraction-related artefacts. Unfortunately, the acquisition of a HAADF-STEM tilt series can easily take up one hour or more, depending
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Investigation of gas-electron interactions with electron holography Ultramicroscopy (IF 2.452) Pub Date : 2020-11-23 Jes Ærøe Hyllested; Marco Beleggia
Using the combination of off-axis electron holography and environmental Transmission Electron Microscopy (TEM), an experimental setup termed 'gas electron holography', we investigate how the presence of gas in the microscope affects the spatial and phase resolution of electron holograms. The gas is introduced either by using an Environmental TEM (ETEM) or a closed-cell holder. The ETEM data on gas
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Implementation and operation of a fiber-coupled CMOS detector in a low energy electron Microscope Ultramicroscopy (IF 2.452) Pub Date : 2020-11-27 D. Janoschka; P. Dreher; A. Rödl; T. Franz; O. Schaff; M. Horn-von Hoegen; F.-J. Meyer zu Heringdorf
The intrinsically weak signals in ultrafast electron microscopy experiments demand an improvement in the signal-to noise ratio of suitable electron detectors. We provide an experience report describing the installation and operation of a fiber-coupled CMOS based detector in a low energy electron microscope. We compare the detector performance to the traditional multi-channel-plate-based setup. The
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Atomically resolved tomographic reconstruction of nanoparticles from single projection: Influence of amorphous carbon support Ultramicroscopy (IF 2.452) Pub Date : 2020-11-23 Pritam Banerjee; Chiranjit Roy; Subhra Kanti De; Antonio J. Santos; Francisco M. Morales; Somnath Bhattacharyya
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TrueEBSD: Correcting spatial distortions in electron backscatter diffraction maps Ultramicroscopy (IF 2.452) Pub Date : 2020-11-04 Vivian S. Tong; T. Ben Britton
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Non-negative matrix factorization for mining big data obtained using four-dimensional scanning transmission electron microscopy Ultramicroscopy (IF 2.452) Pub Date : 2020-11-13 Fumihiko Uesugi; Shogo Koshiya; Jun Kikkawa; Takuro Nagai; Kazutaka Mitsuishi; Koji Kimoto
Scientific instruments for material characterization have recently been improved to yield big data. For instance, scanning transmission electron microscopy (STEM) allows us to acquire many diffraction patterns from a scanning area, which is referred to as four-dimensional (4D) STEM. Here we study a combination of 4D-STEM and a statistical technique called non-negative matrix factorization (NMF) to
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Grain analysis of atomic force microscopy images via persistent homology Ultramicroscopy (IF 2.452) Pub Date : 2020-11-21 Ali Nabi Duman
Atomic force microscopy (AFM) is an established technique in nanoscale grain analysis due to its accuracy in producing 3-dimensional images. Even though height threshold and watershed algorithms are commonly used to determine the grain size and number of grains, they mostly require image processing that result in the change of topographical features of the surface that generates misleading conclusions
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Extraction of 3D quantitative maps using EDS-STEM tomography and HAADF-EDS bimodal tomography Ultramicroscopy (IF 2.452) Pub Date : 2020-11-09 Yu Yuan; Katherine E. MacArthur; Sean M. Collins; Nicolas Brodusch; Frédéric Voisard; Rafal E. Dunin-Borkowski; Raynald Gauvin
Electron tomography has been widely applied to three-dimensional (3D) morphology characterization and chemical analysis at the nanoscale. A HAADF-EDS bimodal tomographic (HEBT) reconstruction technique has been developed to extract high resolution element-specific information. However, the reconstructed elemental maps cannot be directly converted to quantitative compositional information. In this work
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Influence of field conditions on quantitative analysis of single crystal thorium dioxide by atom probe tomography Ultramicroscopy (IF 2.452) Pub Date : 2020-11-09 Amrita Sen; Mukesh Bachhav; Francois Vurpillot; J. Matthew Mann; Phyllis K. Morgan; Timothy A. Prusnick; Janelle P. Wharry
Atom probe tomography (APT), a 3D microscopy technique, has great potential to reveal atomic scale compositional variations, such as those associated with irradiation damage. However, obtaining accurate compositional quantification by APT for high bandgap materials is a longstanding challenge, given the sensitivity to field evaporation parameters and inconsistent behaviors across different oxides.
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Electron backscattered diffraction using a new monolithic direct detector: High resolution and fast acquisition Ultramicroscopy (IF 2.452) Pub Date : 2020-11-04 Fulin Wang; McLean P. Echlin; Aidan A. Taylor; Jungho Shin; Benjamin Bammes; Barnaby D.A. Levin; Marc De Graef; Tresa M. Pollock; Daniel S. Gianola
A monolithic active pixel sensor based direct detector that is optimized for the primary beam energies in scanning electron microscopes is implemented for electron back-scattered diffraction (EBSD) applications. The high detection efficiency of the detector and its large array of pixels allow sensitive and accurate detection of Kikuchi bands arising from primary electron beam excitation energies of
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Off-axis electron holography of Néel-type skyrmions in multilayers of heavy metals and ferromagnets Ultramicroscopy (IF 2.452) Pub Date : 2020-10-24 T. Denneulin; J. Caron; M. Hoffmann; M. Lin; H.K. Tan; A. Kovács; S. Blügel; R.E. Dunin-Borkowski
Magnetic skyrmions are complex swirling spin structures that are of interest for applications in energy-efficient memories and logic technologies. Multilayers of heavy metals and ferromagnets have been shown to host magnetic skyrmions at room temperature. Lorentz transmission electron microscopy is often used to study magnetic domain structures in multilayer samples using mainly Fresnel defocus imaging
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Lattice resolution of vibrational modes in the electron microscope Ultramicroscopy (IF 2.452) Pub Date : 2020-11-04 Peter Rez; Arunima Singh
The combination of aberration correction and ultra high energy resolution with monochromators has made it possible to record images showing lattice resolution in phonon modes, both with a displaced collection aperture and more recently with an on –axis collection aperture. In practice the objective aperture has to include Bragg reflections that correspond to the observed lattice image spacings, and
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FANM: A software for focus and aberrations of nuclear microprobe Ultramicroscopy (IF 2.452) Pub Date : 2020-11-02 Yanxin Dou; Jeroen Anton van Kan
Focus and Aberrations of Nuclear Microprobe (FANM) is a new beam optics package to achieve fast and accurate design of a nuclear microprobe. FANM achieves a balance between speed of focusing and accuracy of high order aberrations. A combined method proposed in FANM is to achieve focusing conditions using a matrix method and to calculate aberration coefficients using a numerical ray tracing method.
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Band gap measurement by nano-beam STEM with small off-axis angle transmission electron energy loss spectroscopy (TEELS) Ultramicroscopy (IF 2.452) Pub Date : 2020-11-02 Yun-Yu Wang; Qiang Jin; Kent Zhuang; Jae Kyu Choi; Jochonia Nxumalo
An energy band gap measurement method based on nano-beam STEM with small off-axis angle valence band transmission electron energy loss spectroscopy (TEELS) is reported. The effect of multiple scattering event is removed by self-convolution method to obtain a single scattering loss function and a dielectric function is calculated from the single scattering valence band energy loss function through Kramers-Kronig
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Ultra-high contrast STEM imaging for segmented/pixelated detectors by maximizing the signal-to-noise ratio Ultramicroscopy (IF 2.452) Pub Date : 2020-10-16 Kousuke Ooe; Takehito Seki; Yuichi Ikuhara; Naoya Shibata
Atomic-resolution low-dose imaging for beam-sensitive materials is one of the most challenging topics in electron microscopy research. In this study, we theoretically developed a new scanning transmission electron microscopy (STEM) imaging technique by maximizing the signal-to-noise ratio of an obtainable image under the weak phase object approximation (WPOA), which we will call optimum bright-field
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A cartridge-based turning specimen holder with wireless tilt angle measurement for magnetic induction mapping in the transmission electron microscope Ultramicroscopy (IF 2.452) Pub Date : 2020-08-31 Patrick Diehle; András Kovács; Thomas Duden; Rolf Speen; Kristina Žagar Soderžnik; Rafal E. Dunin-Borkowski
Magnetic induction mapping in the transmission electron microscope using phase contrast techniques such as off-axis electron holography and differential phase contrast imaging often requires the separation of the magnetic contribution to the recorded signal from the electrostatic contribution. When using off-axis electron holography, one of the experimental approaches that can be used to achieve this
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Flat electron mirror Ultramicroscopy (IF 2.452) Pub Date : 2020-11-02 M.A.R. Krielaart; P. Kruit
Electron beams can be reflected by an electrode that is at a more negative potential than the cathode from which the beam is emitted. We want to design a mirror with a flat mirror electrode where the electrons are reflected at a plane very close to the electrode. The wave front of an electron can then be shaped when the mirror contains a surface topography or modulated potential. However, electron
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Laser ablation sample preparation for atom probe tomography and transmission electron microscopy Ultramicroscopy (IF 2.452) Pub Date : 2020-11-02 N. White; K. Eder; J. Byrnes; J.M. Cairney; I.E. McCarroll
Laser ablation is capable of removing large volumes of material with micron scale precision at very high speeds. This makes it an ideal tool for the initial stage of preparation of samples for atom probe and electron microscopy studies. However, the thermal nature of the laser ablation process is such that thermal and mechanical damage is induced in the samples in the form of zones of recrystallisation
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Experimental quantification of atomically-resolved HAADF-STEM images using EDX Ultramicroscopy (IF 2.452) Pub Date : 2020-10-28 K. Pantzas; G. Patriarche
Atomically-resolved mappings of the indium composition in InGaN/GaN multi-quantum well structures have been obtained by quantifying the contrast in HAADF-STEM. The quantification procedure presented here does not rely on computation-intensive simulations, but rather uses EDX measurements to calibrate the HAADF-STEM contrast. The histogram of indium compositions obtained from the mapping provides unique
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Three dimensional cluster analysis for atom probe tomography using Ripley’s K-function and machine learning Ultramicroscopy (IF 2.452) Pub Date : 2020-10-28 Galen B. Vincent; Andrew P. Proudian; Jeramy D. Zimmerman
The size and structure of spatial molecular and atomic clustering can significantly impact material properties and is therefore important to accurately quantify. Ripley’s K-function (K(r)), a measure of spatial correlation, can be used to perform such quantification when the material system of interest can be represented as a marked point pattern. This work demonstrates how machine learning models
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Autofocus of whole slide imaging based on convolution and recurrent neural networks Ultramicroscopy (IF 2.452) Pub Date : 2020-10-22 Yao Xiang; Zhujun He; Qing Liu; Jialin Chen; Yixiong Liang
During the process of whole slide imaging, it is necessary to focus thousands of fields of view to obtain a high-quality image. To make the focusing procedure efficient and effective, we propose a novel autofocus algorithm for whole slide imaging. It is based on convolution and recurrent neural networks to predict the out-of-focus distance and subsequently update the focus location of the camera lens
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Effect of native oxide on the crystal orientation contrast in SEM micrographs obtained at hundreds, tens and units of eV Ultramicroscopy (IF 2.452) Pub Date : 2020-10-21 Šárka Mikmeková; Tomohiro Aoyama
This paper aims to elucidate the effect of native air-formed oxide on the crystallographic contrast between differently oriented copper grains in scanning electron microscope images obtained at energies from 0 eV up to 1 keV. The contrast between the Cu grains is strongly affected by the presence of native oxide. The crystallographic orientation contrast between the grains without covering the native
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Local electronic transport across probe/ionic conductor interface in scanning probe microscopy Ultramicroscopy (IF 2.452) Pub Date : 2020-10-21 K.N. Romanyuk; D.O. Alikin; B.N. Slautin; A. Tselev; V.Ya. Shur; A.L. Kholkin
Charge carrier transport through the probe-sample junction can have substantial consequences for outcomes of electrical and electromechanical atomic-force-microscopy (AFM) measurements. For understanding physical processes under the probe, we carried out conductive-AFM (C-AFM) measurements of local current-voltage (I-V) curves as well as their derivatives on samples of a mixed ionic-electronic conductor
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Atom probe tomography quantification of carbon in silicon Ultramicroscopy (IF 2.452) Pub Date : 2020-10-24 P. Dumas; S. Duguay; J. Borrel; F. Hilario; D. Blavette
Atom Probe Tomography (APT) was used to quantify carbon in implanted silicon at two various electric fields (~ 15 and 20 V/nm). Using equal proportions of implanted 12C and 13C, the numerous molecular ions that were observed were identified and their contribution to the carbon content statistically derived. Much more accurate carbon quantification was obtained in the lowest electric field analysis
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Core hole screened electron energy loss calculations of beam damaged lithium fluoride Ultramicroscopy (IF 2.452) Pub Date : 2020-09-24 Quentin Stoyel; Frédéric Voisard; Nicolas Brodusch; George P. Demopoulos; Karim Zaghib; Raynald Gauvin
A method of calculating the magnitude of the core hole screening of lithium materials is implemented for the simulation of Energy Loss Near Edge Structure (ELNES). ELNES is calculated for a range of lithium materials resulting in improved agreement between calculation and experiment. The technique uses linear response theory to relate the electron density to the core hole shielding contribution from
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Hidden Markov model for atom-counting from sequential ADF STEM images: Methodology, possibilities and limitations Ultramicroscopy (IF 2.452) Pub Date : 2020-10-03 Annelies De wael; Annick De Backer; Sandra Van Aert
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
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Orientation mapping of graphene using 4D STEM-in-SEM Ultramicroscopy (IF 2.452) Pub Date : 2020-10-13 Benjamin W. Caplins; Jason D. Holm; Ryan M. White; Robert R. Keller
A scanning diffraction technique is implemented in the scanning electron microscope. The technique, referred to as 4D STEM-in-SEM (four-dimensional scanning transmission electron microscopy in the scanning electron microscope), collects a diffraction pattern from each point on a sample which is saved to disk for further analysis. The diffraction patterns are collected using an on-axis lens-coupled
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Dynamic compressed sensing for real-time tomographic reconstruction Ultramicroscopy (IF 2.452) Pub Date : 2020-10-09 Jonathan Schwartz; Huihuo Zheng; Marcus Hanwell; Yi Jiang; Robert Hovden
Electron tomography has achieved higher resolution and quality at reduced doses with recent advances in compressed sensing. Compressed sensing (CS) exploits the inherent sparse signal structure to efficiently reconstruct three-dimensional (3D) volumes at the nanoscale from undersampled measurements. However, the process bottlenecks 3D reconstruction with computation times that run from hours to days
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Origin and Suppression of Beam Damage-Induced Oxygen-K Edge Artifact from γ-Al2O3 using Cryo-EELS Ultramicroscopy (IF 2.452) Pub Date : 2020-10-01 Henry O. Ayoola; Cheng-Han Li; Stephen D. House; Cecile S. Bonifacio; Kim Kisslinger; Joerg Jinschek; Wissam A. Saidi; Judith C. Yang
Gamma-alumina (γ-Al2O3), like other low-Z oxides, is readily damaged when exposed to an electron beam. This typically results in the formation of a characteristic pre-edge peak in the oxygen-K edge of electron energy-loss spectra (EELS) acquired during or after the damage process. This artifact can mask the presence of intrinsic O-K edge fine structure that would reveal chemical properties of the material;
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Spherical-angular dark field imaging and sensitive microstructural phase clustering with unsupervised machine learning Ultramicroscopy (IF 2.452) Pub Date : 2020-10-08 T.P. McAuliffe; D. Dye; T.B. Britton
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An in-situ method for protecting internal cracks/pores from ion beam damage and reducing curtaining for TEM sample preparation using FIB Ultramicroscopy (IF 2.452) Pub Date : 2020-10-10 Xiang Li Zhong; Sarah J Haigh; Xiaorong Zhou; Philip J Withers
Focused ion beam (FIB) milling has evolved to be one of the most important Transmission Electron Microscope (TEM) site specific sample preparation techniques. However, this technique still poses challenges, such as the structural damage and potential curtaining issues often observed for thin TEM lamella. These artefacts can negatively affect the TEM analysis results. In particular, structures such
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High resolution atomic scale characterization of dislocations in high entropy alloys: critical assessment of template matching and geometric phase analysis Ultramicroscopy (IF 2.452) Pub Date : 2020-10-07 F. Brenne; A.S.K. Mohammed; H. Sehitoglu
The paper assesses the applicability of advanced atomic resolution displacement measurement techniques to characterize dislocation character in metallic materials using simulated images derived from anisotropic elasticity and actual measurements in high entropy alloys. We draw attention to two techniques: the real space method of template matching (TeMA) and the reciprocal space method of geometric
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Dissecting complex nanoparticle heterostructures via multimodal data fusion with aberration-corrected STEM spectroscopy Ultramicroscopy (IF 2.452) Pub Date : 2020-09-23 Thomas Thersleff; Serhiy Budnyk; Larissa Drangai; Adam Slabon
With nanostructured materials such as catalytic heterostructures projected to play a critical role in applications ranging from water splitting to energy harvesting, tailoring their properties to specific tasks requires an increasingly comprehensive characterization of their local chemical and electronic landscape. Although aberration-corrected electron spectroscopy currently provides sufficient spatial
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Denoising atomic resolution 4D scanning transmission electron microscopy data with tensor singular value decomposition Ultramicroscopy (IF 2.452) Pub Date : 2020-09-25 Chenyu Zhang; Rungang Han; Anru R. Zhang; Paul.M. Voyles
Tensor singular value decomposition (SVD) is a method to find a low-dimensional representation of data with meaningful structure in three or more dimensions. Tensor SVD has been applied to denoise atomic-resolution 4D scanning transmission electron microscopy (4D STEM) data. On data simulated from a SrTiO3 [100] perfect crystal and a Si [110] edge dislocation, tensor SVD achieved an average peak signal-to-noise
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Scanning transmission electron microscopy image simulations of complex dislocation structures generated by discrete dislocation dynamics Ultramicroscopy (IF 2.452) Pub Date : 2020-09-24 Joseph Tessmer; Saransh Singh; Yejun Gu; Jaafar A. El-Awady; Marc De Graef
Scanning Transmission Electron Microscopy Diffraction Contrast Imaging (STEM-DCI) has been gaining popularity for the identification and analysis of dislocations in crystalline materials due to its ability to supress undesirable image features that are often present in conventional TEM images. However, there does not yet exist a robust body of work demonstrating expected contrast in these imaging conditions
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Deep learning for scanning electron microscopy: Synthetic data for the nanoparticles detection Ultramicroscopy (IF 2.452) Pub Date : 2020-09-25 A. Yu. Kharin
Deep learning algorithms are one of most rapid developing fields into the modern computation technologies. One of the bottlenecks into the implementation of such advaced algorithms is their requirement for a large amount of manually-labelled data for training. For the general-purpose tasks, such as general purpose image classification/detection the huge images datasets are already labelled and collected
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Inverse modeling for quantitative X-ray microanalysis applied to 2D heterogeneous materials Ultramicroscopy (IF 2.452) Pub Date : 2020-09-20 Yu Yuan; Hendrix Demers; Nicolas Brodusch; Xianglong Wang; Raynald Gauvin
Current quantitative X-ray microanalysis methods are only available for homogeneous materials. This paper presents a newly developed inverse modeling algorithm to determine both the structure and composition of two-dimensional (2D) heterogeneous materials from a series of X-ray intensity measurements under different beam energies and beam positions. It utilizes an iterative process of forward modeling
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Lattice contrast in the core-loss EFTEM signal of graphene Ultramicroscopy (IF 2.452) Pub Date : 2020-09-19 Michael J. Mohn; Johannes Biskupek; Zhongbo Lee; Harald Rose; Ute Kaiser
The realization of chromatic aberration correction enables energy-filtered transmission electron microscopy (EFTEM) at atomic resolution even for large energy windows. Previous works have demonstrated lattice contrast from ionization-edge signals such as the L2,3 edges of silicon or titanium. However, the direct interpretation as chemical information was found to be hampered by contributions from elastic
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Theoretical modeling and simulation-based assessment of graded-bandgap AlGaAs/GaAs electron-injection cathode Ultramicroscopy (IF 2.452) Pub Date : 2020-09-14 Juyang Xia; Jijun Zou; Xincun Peng; Wenjuan Deng; Yijun Zhang
The electron emission model of a negative electron affinity graded-bandgap AlGaAs/GaAs electron-injection cathode was developed from two-dimensional continuity equations. The emission current was obtained from a simulation of the model, and the emission current efficiency and emission current per unit length were calculated. Based on the simulation results and preparation conditions, the range of optimum
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Dual-Probe Atomic Force Microscopy based on tuning fork probes for critical dimension metrology Ultramicroscopy (IF 2.452) Pub Date : 2020-09-19 Zhiyue Zheng; Sitian Gao; Wei Li; Xiaojun Liu; Yushu Shi; Cheng Chen
Atomic force microscopy (AFM) is widely used for nano-dimensional metrology in semiconductor manufacturing and metrological system. However, the conventional AFM can't provide accurate CD characterization of nanostructures, due to its top-down configuration and probe-size effect. In this paper, we develop a dual-probe atomic force microscopy (DPAFM). Compared to conventional optical-lever based AFM
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Influence of lens aberrations, specimen thickness and tilt on differential phase contrast STEM images Ultramicroscopy (IF 2.452) Pub Date : 2020-09-17 Julius Bürger; Thomas Riedl; Jörg K.N. Lindner
Differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM) allows for measuring electric and magnetic fields in solids on scales ranging from picometres to micrometres. The DPC technique mainly uses the direct beam, which is deflected by the electric and magnetic fields of the specimen and measured with a beam position sensitive detector. The beam deflection and thus
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HAADF-STEM block-scanning strategy for local measurement of strain at the nanoscale. Ultramicroscopy (IF 2.452) Pub Date : 2020-09-01 V Prabhakara,D Jannis,G Guzzinati,A Béché,H Bender,J Verbeeck
Lattice strain measurement of nanoscale semiconductor devices is crucial for the semiconductor industry as strain substantially improves the electrical performance of transistors. High resolution scanning transmission electron microscopy (HR-STEM) imaging is an excellent tool that provides spatial resolution at the atomic scale and strain information by applying Geometric Phase Analysis or image fitting
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Suppressing dynamical diffraction artefacts in differential phase contrast scanning transmission electron microscopy of long-range electromagnetic fields via precession. Ultramicroscopy (IF 2.452) Pub Date : 2020-08-28 T Mawson,A Nakamura,T C Petersen,N Shibata,H Sasaki,D M Paganin,M J Morgan,S D Findlay
It is well known that dynamical diffraction varies with changes in sample thickness and local crystal orientation (due to sample bending). In differential phase contrast scanning transmission electron microscopy (DPC-STEM), this can produce contrast comparable to that arising from the long-range electromagnetic fields probed by this technique. Through simulation we explore the scale of these dynamical
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FIB/SEM tomography segmentation by optical flow estimation. Ultramicroscopy (IF 2.452) Pub Date : 2020-08-27 Riko Moroni,Simon Thiele
Focused ion beam/scanning electron microscopy tomography (FIB/SEM tomography) is the method of choice for the tomographic reconstruction of mesoporous materials systems in various fields such as batteries, fuel cells, filter applications or composite materials. However, due to so called shine-through artifacts in FIB/SEM tomographies of porous materials, their segmentation into pore space and solid
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