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Author | Jannis, D.; Hofer, C.; Gao, C.; Xie, X.; Béché, A.; Pennycook, Tj.; Verbeeck, J. | ||||
Title | Event driven 4D STEM acquisition with a Timepix3 detector: Microsecond dwell time and faster scans for high precision and low dose applications | Type | A1 Journal article | ||
Year | 2022 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 233 | Issue | Pages | 113423 | |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | Four dimensional scanning transmission electron microscopy (4D STEM) records the scattering of electrons in a material in great detail. The benefits offered by 4D STEM are substantial, with the wealth of data it provides facilitating for instance high precision, high electron dose efficiency phase imaging via centre of mass or ptychography based analysis. However the requirement for a 2D image of the scattering to be recorded at each probe position has long placed a severe bottleneck on the speed at which 4D STEM can be performed. Recent advances in camera technology have greatly reduced this bottleneck, with the detection efficiency of direct electron detectors being especially well suited to the technique. However even the fastest frame driven pixelated detectors still significantly limit the scan speed which can be used in 4D STEM, making the resulting data susceptible to drift and hampering its use for low dose beam sensitive applications. Here we report the development of the use of an event driven Timepix3 direct electron camera that allows us to overcome this bottleneck and achieve 4D STEM dwell times down to 100 ns; orders of magnitude faster than what has been possible with frame based readout. We characterize the detector for different acceleration voltages and show that the method is especially well suited for low dose imaging and promises rich datasets without compromising dwell time when compared to conventional STEM imaging. | ||||
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Language | Wos | 000734396800003 | Publication Date | 2021-11-13 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 31 | Open Access | OpenAccess |
Notes | This project has received funding from the Euro- pean Union’s Horizon 2020 Research Infrastructure – Integrating Activities for Advanced Communities under grant agreement No 823717 – ESTEEM3. J.V. and A.B. acknowledge funding from FWO project G093417N (‘Compressed sensing enabling low dose imaging in transmission electron microscopy’). J.V. and D.J. ac- knowledge funding from FWO project G042920N ‘Co- incident event detection for advanced spectroscopy in transmission electron microscopy’. We acknowledge funding under the European Union’s Horizon 2020 re- search and innovation programme (J.V. and D.J un- der grant agreement No 101017720, FET-Proactive EBEAM, and C.H., C.G., X.X. and T.J.P. from the Eu- ropean Research Council (ERC) Grant agreement No. 802123-HDEM).; esteem3JRA; esteem3reported | Approved | Most recent IF: 2.2 | ||
Call Number | EMAT @ emat @c:irua:183948 | Serial | 6828 | ||
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Author | Hofer, C.; Pennycook, T.J. | ||||
Title | Reliable phase quantification in focused probe electron ptychography of thin materials | Type | A1 Journal Article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 254 | Issue | Pages | 113829 | |
Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
Abstract | Electron ptychography provides highly sensitive, dose efficient phase images which can be corrected for aberrations after the data has been acquired. This is crucial when very precise quantification is required, such as with sensitivity to charge transfer due to bonding. Drift can now be essentially eliminated as a major impediment to focused probe ptychography, which benefits from the availability of easily interpretable simultaneous Z-contrast imaging. However challenges have remained when quantifying the ptychographic phases of atomic sites. The phase response of a single atom has a negative halo which can cause atoms to reduce in phase when brought closer together. When unaccounted for, as in integrating methods of quantification, this effect can completely obscure the effects of charge transfer. Here we provide a new method of quantification that overcomes this challenge, at least for 2D materials, and is robust to experimental parameters such as noise, sample tilt. | ||||
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Language | Wos | 001071608700001 | Publication Date | 2023-08-18 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | ||
Notes | FWO, G013122N ; Horizon 2020 Framework Programme; Horizon 2020; European Research Council, 802123-HDEM ; European Research Council; | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:200272 | Serial | 8987 | ||
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Author | Robert, Hl.; Lobato, I.; Lyu, Fj.; Chen, Q.; Van Aert, S.; Van Dyck, D.; Müller-Caspary, K. | ||||
Title | Dynamical diffraction of high-energy electrons investigated by focal series momentum-resolved scanning transmission electron microscopy at atomic resolution | Type | A1 Journal article | ||
Year | 2022 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 233 | Issue | Pages | 113425 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | We report a study of scattering dynamics in crystals employing momentum-resolved scanning transmission electron microscopy under varying illumination conditions. As we perform successive changes of the probe focus, multiple real-space signals are obtained in dependence of the shape of the incident electron wave. With support from extensive simulations, each signal is shown to be characterised by an optimum focus for which the contrast is maximum and which differs among different signals. For instance, a systematic focus mismatch is found between images formed by high-angle scattering, being sensitive to thickness and chemical composition, and the first moment in diffraction space, being sensitive to electric fields. It follows that a single recording at one specific probe focus is usually insufficient to characterise materials comprehensively. Most importantly, we demonstrate in experiment and simulation that the second moment ( |
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Language | Wos | 000734396800009 | Publication Date | 2021-11-13 | |
Series Editor | Series Title | Abbreviated Series Title | |||
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | We thank Dr. Florian Winkler for valuable discussions and experimental work at the early stages of this study. This work was supported by the Initiative and Network Fund of the Helmholtz Association (Germany) under contracts VH-NG-1317 and ZT-I-0025. This project furthermore received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 770887). | Approved | Most recent IF: 2.2 | ||
Call Number | EMAT @ emat @c:irua:184833 | Serial | 6898 | ||
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Author | Jannis, D.; Velazco, A.; Béché, A.; Verbeeck, J. | ||||
Title | Reducing electron beam damage through alternative STEM scanning strategies, Part II: Attempt towards an empirical model describing the damage process | Type | A1 Journal article | ||
Year | 2022 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | Issue | Pages | 113568 | ||
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | In this second part of a series we attempt to construct an empirical model that can mimick all experimental observations made regarding the role of an alternative interleaved scan pattern in STEM imaging on the beam damage in a specific zeolite sample. We make use of a 2D diffusion model that describes the dissipation of the deposited beam energy in the sequence of probe positions that are visited during the scan pattern. The diffusion process allows for the concept of trying to ‘outrun’ the beam damage by carefully tuning the dwell time and distance between consecutively visited probe positions. We add a non linear function to include a threshold effect and evaluate the accumulated damage in each part of the image as a function of scan pattern details. Together, these ingredients are able to describe qualitatively all aspects of the experimental data and provide us with a model that could guide a further optimisation towards even lower beam damage without lowering the applied electron dose. We deliberately remain vague on what is diffusing here which avoids introducing too many sample specific details. This provides hope that the model can be applied also in sample classes that were not yet studied in such great detail by adjusting higher level parameters: a sample dependent diffusion constant and damage threshold. | ||||
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Language | Wos | 000832788000003 | Publication Date | 0000-00-00 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 4 | Open Access | OpenAccess |
Notes | D.J., A.V, A.B. and J.V. acknowledge funding from FWO project G093417N (’Compressed sensing enabling low dose imaging in transmission electron microscopy’) and G042920N (’Coincident event detection for advanced spectroscopy in transmission electron microscopy’). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 823717 ESTEEM3. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. J.V. acknowledges funding from GOA project “Solarpaint” of the University of Antwerp .; esteem3reported; esteem3jra; | Approved | Most recent IF: 2.2 | ||
Call Number | EMAT @ emat @c:irua:188535 | Serial | 7071 | ||
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Author | Hofer, C.; Gao, C.; Chennit, T.; Yuan, B.; Pennycook, T.J. | ||||
Title | Phase offset method of ptychographic contrast reversal correction | Type | A1 Journal article | ||
Year | 2024 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | Issue | Pages | 113922 | ||
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
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Language | Wos | 001164447000001 | Publication Date | 2024-01-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.2 | Times cited | Open Access | Not_Open_Access | |
Notes | FWO, G013122N ; Horizon 2020 Framework Programme; European Research Council, 802123-HDEM ; European Research Council; | Approved | Most recent IF: 2.2; 2024 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:202379 | Serial | 8988 | ||
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Author | Sentürk, D.G.; De Backer, A.; Friedrich, T.; Van Aert, S. | ||||
Title | Optimal experiment design for element specific atom counting using multiple annular dark field scanning transmission electron microscopy detectors | Type | A1 Journal article | ||
Year | 2022 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 242 | Issue | Pages | 113626 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | This paper investigates the possible benefits for counting atoms of different chemical nature when analysing multiple 2D scanning transmission electron microscopy (STEM) images resulting from independent annular dark field (ADF) detector regimes. To reach this goal, the principles of statistical detection theory are used to quantify the probability of error when determining the number of atoms in atomic columns consisting of multiple types of elements. In order to apply this theory, atom-counting is formulated as a statistical hypothesis test, where each hypothesis corresponds to a specific number of atoms of each atom type in an atomic column. The probability of error, which is limited by the unavoidable presence of electron counting noise, can then be computed from scattering-cross sections extracted from multiple ADF STEM images. Minimisation of the probability of error as a function of the inner and outer angles of a specified number of independent ADF collection regimes results in optimal experimental designs. Based on simulations of spherical Au@Ag and Au@Pt core–shell nanoparticles, we investigate how the combination of two non-overlapping detector regimes helps to improve the probability of error when unscrambling two types of atoms. In particular, the combination of a narrow low angle ADF detector with a detector formed by the remaining annular collection regime is found to be optimal. The benefit is more significant if the atomic number Z difference becomes larger. In addition, we show the benefit of subdividing the detector regime into three collection areas for heterogeneous nanostructures based on a structure consisting of three types of elements, e.g., a mixture of Au, Ag and Al atoms. Finally, these results are compared with the probability of error resulting when one would ultimately use a pixelated 4D STEM detector and how this could help to further reduce the incident electron dose. |
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Language | Wos | 000873778100001 | Publication Date | 0000-00-00 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert and Grant 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0346.21N and EOS 30489208) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF).; esteem3reported; esteem3jra | Approved | Most recent IF: 2.2 | ||
Call Number | EMAT @ emat @c:irua:190925 | Serial | 7118 | ||
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Author | De Backer, A.; Bals, S.; Van Aert, S. | ||||
Title | A decade of atom-counting in STEM: From the first results toward reliable 3D atomic models from a single projection | Type | A1 Journal article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | |
Volume | Issue | Pages | 113702 | ||
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Quantitative structure determination is needed in order to study and understand nanomaterials at the atomic scale. Materials characterisation resulting in precise structural information is a crucial point to understand the structure–property relation of materials. Counting the number of atoms and retrieving the 3D atomic structure of nanoparticles plays an important role here. In this paper, an overview will be given of the atom-counting methodology and its applications over the past decade. The procedure to count the number of atoms will be discussed in detail and it will be shown how the performance of the method can be further improved. Furthermore, advances toward mixed element nanostructures, 3D atomic modelling based on the atom-counting results, and quantifying the nanoparticle dynamics will be highlighted. | ||||
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Language | Wos | 000953765800001 | Publication Date | 2023-02-10 | |
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | 3 | Open Access | OpenAccess |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert, Grant 815128 REALNANO to S. Bals, and Grant 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0267.18N, G.0502.18N, G.0346.21N, and EOS 30489208) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF) . The authors also thank the colleagues who have contributed to this work over the years, including T. Altantzis, E. Arslan Irmak, K.J. Batenburg, E. Bladt, A. De wael, R. Erni, C. Faes, B. Goris, L. Jones, L.M. Liz-Marzán, I. Lobato, G.T. Martinez, P.D. Nellist, M.D. Rosell, A. Rosenauer, K.H.W. van den Bos, A. Varambhia, and Z. Zhang.; esteem3reported; esteem3JRA | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:195896 | Serial | 7236 | ||
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Author | Zhang, Z.; Lobato, I.; De Backer, A.; Van Aert, S.; Nellist, P. | ||||
Title | Fast generation of calculated ADF-EDX scattering cross-sections under channelling conditions | Type | A1 Journal article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | |
Volume | 246 | Issue | Pages | 113671 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Advanced materials often consist of multiple elements which are arranged in a complicated structure. Quantitative scanning transmission electron microscopy is useful to determine the composition and thickness of nanostructures at the atomic scale. However, significant difficulties remain to quantify mixed columns by comparing the resulting atomic resolution images and spectroscopy data with multislice simulations where dynamic scattering needs to be taken into account. The combination of the computationally intensive nature of these simulations and the enormous amount of possible mixed column configurations for a given composition indeed severely hamper the quantification process. To overcome these challenges, we here report the development of an incoherent non-linear method for the fast prediction of ADF-EDX scattering cross-sections of mixed columns under channelling conditions. We first explain the origin of the ADF and EDX incoherence from scattering physics suggesting a linear dependence between those two signals in the case of a high-angle ADF detector. Taking EDX as a perfect incoherent reference mode, we quantitatively examine the ADF longitudinal incoherence under different microscope conditions using multislice simulations. Based on incoherent imaging, the atomic lensing model previously developed for ADF is now expanded to EDX, which yields ADF-EDX scattering cross-section predictions in good agreement with multislice simulations for mixed columns in a core–shell nanoparticle and a high entropy alloy. The fast and accurate prediction of ADF-EDX scattering cross-sections opens up new opportunities to explore the wide range of ordering possibilities of heterogeneous materials with multiple elements. | ||||
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Corporate Author | Zezhong Zhang | Thesis | |||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000995063900001 | Publication Date | 2022-12-28 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | European Research Council 770887 PICOMETRICS; Fonds Wetenschappelijk Onderzoek No.G.0502.18N; Horizon 2020, 770887 ; Horizon 2020 Framework Programme; European Research Council, 823717 ESTEEM3 ; esteem3reported; esteem3JRa | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:195890 | Serial | 7251 | ||
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Author | Lobato, I.; De Backer, A.; Van Aert, S. | ||||
Title | Real-time simulations of ADF STEM probe position-integrated scattering cross-sections for single element fcc crystals in zone axis orientation using a densely connected neural network | Type | A1 Journal article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 251 | Issue | Pages | 113769 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Quantification of annular dark field (ADF) scanning transmission electron microscopy (STEM) images in terms of composition or thickness often relies on probe-position integrated scattering cross sections (PPISCS). In order to compare experimental PPISCS with theoretically predicted ones, expensive simulations are needed for a given specimen, zone axis orientation, and a variety of microscope settings. The computation time of such simulations can be in the order of hours using a single GPU card. ADF STEM simulations can be efficiently parallelized using multiple GPUs, as the calculation of each pixel is independent of other pixels. However, most research groups do not have the necessary hardware, and, in the best-case scenario, the simulation time will only be reduced proportionally to the number of GPUs used. In this manuscript, we use a learning approach and present a densely connected neural network that is able to perform real-time ADF STEM PPISCS predictions as a function of atomic column thickness for most common face-centered cubic (fcc) crystals (i.e., Al, Cu, Pd, Ag, Pt, Au and Pb) along [100] and [111] zone axis orientations, root-mean-square displacements, and microscope parameters. The proposed architecture is parameter efficient and yields accurate predictions for the PPISCS values for a wide range of input parameters that are commonly used for aberration-corrected transmission electron microscopes. |
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Language | Wos | 001011617200001 | Publication Date | 2023-06-01 | |
Series Editor | Series Title | Abbreviated Series Title | |||
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G034621N and G0A7723N) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF), Belgium. | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:197275 | Serial | 8812 | ||
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Author | Denisov, N.; Jannis, D.; Orekhov, A.; Müller-Caspary, K.; Verbeeck, J. | ||||
Title | Characterization of a Timepix detector for use in SEM acceleration voltage range | Type | A1 Journal article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 253 | Issue | Pages | 113777 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Hybrid pixel direct electron detectors are gaining popularity in electron microscopy due to their excellent properties. Some commercial cameras based on this technology are relatively affordable which makes them attractive tools for experimentation especially in combination with an SEM setup. To support this, a detector characterization (Modulation Transfer Function, Detective Quantum Efficiency) of an Advacam Minipix and Advacam Advapix detector in the 15–30 keV range was made. In the current work we present images of Point Spread Function, plots of MTF/DQE curves and values of DQE(0) for these detectors. At low beam currents, the silicon detector layer behaviour should be dominant, which could make these findings transferable to any other available detector based on either Medipix2, Timepix or Timepix3 provided the same detector layer is used. | ||||
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Language | Wos | 001026912700001 | Publication Date | 2023-06-08 | |
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | The authors acknowledge the financial support of the Research Foundation Flanders (FWO, Belgium) project SBO S000121N. The authors are grateful to Dr. Lobato for productive discussion of methods. | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:198258 | Serial | 8815 | ||
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Author | Şentürk, DG.; Yu, CP.; De Backer, A.; Van Aert, S. | ||||
Title | Atom counting from a combination of two ADF STEM images | Type | A1 Journal article | ||
Year | 2024 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 255 | Issue | Pages | 113859 | |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
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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Language | Wos | 001089064200001 | Publication Date | 2023-09-23 | |
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G034621N, G0A7723N, and EOS 40007495) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF). | Approved | Most recent IF: 2.2; 2024 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:201008 | Serial | 8964 | ||
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Author | Van den Broek, W.; Jannis, D.; Verbeeck, J. | ||||
Title | Convexity constraints on linear background models for electron energy-loss spectra | Type | A1 Journal Article | ||
Year | 2023 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 254 | Issue | Pages | 113830 | |
Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
Abstract | In this paper convexity constraints are derived for a background model of electron energy loss spectra (EELS) that is linear in the fitting parameters. The model outperforms a power-law both on experimental and simulated backgrounds, especially for wide energy ranges, and thus improves elemental quantification results. Owing to the model’s linearity, the constraints can be imposed through fitting by quadratic programming. This has important advantages over conventional nonlinear power-law fitting such as high speed and a guaranteed unique solution without need for initial parameters. As such, the need for user input is significantly reduced, which is essential for unsupervised treatment of large datasets. This is demonstrated on a demanding spectrum image of a semiconductor device sample with a high number of elements over a wide energy range. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2023-08-15 | ||
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record | |
Impact Factor | 2.2 | Times cited | Open Access | Not_Open_Access | |
Notes | ECSEL, 875999 ; Horizon 2020; Horizon 2020 Framework Programme; Electronic Components and Systems for European Leadership; | Approved | Most recent IF: 2.2; 2023 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:200588 | Serial | 8961 | ||
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Author | Şentürk, D.G.; De Backer, A.; Van Aert, S. | ||||
Title | Element specific atom counting for heterogeneous nanostructures: Combining multiple ADF STEM images for simultaneous thickness and composition determination | Type | A1 Journal Article | ||
Year | 2024 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 259 | Issue | Pages | 113941 | |
Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
Abstract | In this paper, a methodology is presented to count the number of atoms in heterogeneous nanoparticles based on the combination of multiple annular dark field scanning transmission electron microscopy (ADF STEM) images. The different non-overlapping annular detector collection regions are selected based on the principles of optimal statistical experiment design for the atom-counting problem. To count the number of atoms, the total intensities of scattered electrons for each atomic column, the so-called scattering cross-sections, are simultaneously compared with simulated library values for the different detector regions by minimising the squared differences. The performance of the method is evaluated for simulated Ni@Pt and Au@Ag core-shell nanoparticles. Our approach turns out to be a dose efficient alternative for the investigation of beam-sensitive heterogeneous materials as compared to the combination of ADF STEM and energy dispersive X-ray spectroscopy. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2024-02-19 | ||
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ISSN | 0304-3991 | ISBN | Additional Links | UA library record | |
Impact Factor | 2.2 | Times cited | Open Access | OpenAccess | |
Notes | This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0346.21N, GOA7723N, and EOS 40007495) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF). | Approved | Most recent IF: 2.2; 2024 IF: 2.843 | ||
Call Number | EMAT @ emat @c:irua:204353 | Serial | 8996 | ||
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Author | De Meulenaere, P.; van Dyck, D.; Van Tendeloo, G.; van Landuyt, J. | ||||
Title | Dynamical electron diffraction in substitutionally disordered column structures | Type | A1 Journal article | ||
Year | 1995 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 60 | Issue | 1 | Pages | 171-185 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | For column structures, such as fee-based alloys viewed along the cube direction, the concept of electron channelling through the atom columns is more and more used to interpret the corresponding HREM images. In the case of(partially) disordered columns, the projected potential approach which is used in the channelling description must be questioned since the arrangement of the atoms along the beam direction might affect the exit wave of the electrons. In this paper, we critically inspect this top-bottom effect using multi-slice calculations. A modified channelling theory is introduced which turns out to be very appropriate for the interpretation of these results. For substitutionally disordered column structures, it is also discussed how to link the chemical composition of the material to statistical data of the HREM image. This results in a convenient tool to discern images taken at different thicknesses and focus values. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | A1995TG59500017 | Publication Date | 2002-07-25 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.436 | Times cited | 14 | Open Access | |
Notes | Approved | no | |||
Call Number | UA @ lucian @ c:irua:13013 | Serial | 770 | ||
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Author | van Landuyt, J. | ||||
Title | The evolution of HVEM application in antwerp | Type | A1 Journal article | ||
Year | 1991 | Publication | Ultramicroscopy T2 – 2nd Osaka International Symp.on High-Voltage Electron Microscopy : New Directions and Future Aspects of High Voltage Electron Microscopy, November 8-10, 1990, Osaka University, Osaka, Japan | Abbreviated Journal | Ultramicroscopy |
Volume | 39 | Issue | 1-4 | Pages | 287-298 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | The evolution of the use of the 1250 keV high-voltage electron microscope in Antwerp is sketched by illustrating a non-exhaustive set of examples in various fields. One of the main present fields of application gets some more attention, i.e. the defect studies as produced by processing steps in microelectronic devices: (i) strain-induced dislocations at the edges of various device isolation interlayers, (ii) morphologies resulting from high-energy ion implantation creating buried layers for silicon on insulator (SOI) and other implantation technologies. | ||||
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Corporate Author | Thesis | ||||
Publisher | Elsevier | Place of Publication | Amsterdam | Editor | |
Language | Wos | A1991GY23100034 | Publication Date | 2002-10-18 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.436 | Times cited | Open Access | ||
Notes | Approved | PHYSICS, APPLIED 47/145 Q2 # | |||
Call Number | UA @ lucian @ c:irua:95973 | Serial | 3579 | ||
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Author | Croitoru, M.D.; van Dyck, D.; Van Aert, S.; Bals, S.; Verbeeck, J. | ||||
Title | An efficient way of including thermal diffuse scattering in simulation of scanning transmission electron microscopic images | Type | A1 Journal article | ||
Year | 2006 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 106 | Issue | 10 | Pages | 933-940 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Vision lab | ||||
Abstract | We propose an improved image simulation procedure for atomic-resolution annular dark-field scanning transmission electron microscopy (STEM) based on the multislice formulation, which takes thermal diffuse scattering fully into account. The improvement with regard to the classical frozen phonon approach is realized by separating the lattice configuration statistics from the dynamical scattering so as to avoid repetitive calculations. As an example, the influence of phonon scattering on the image contrast is calculated and investigated. STEM image simulation of crystals can be applied with reasonable computing times to problems involving a large number of atoms and thick or large supercells. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000240397200006 | Publication Date | 2006-05-10 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 18 | Open Access | |
Notes | Fwo; Fwo-V | Approved | Most recent IF: 2.843; 2006 IF: 1.706 | ||
Call Number | UA @ lucian @ c:irua:87604UA @ admin @ c:irua:87604 | Serial | 876 | ||
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Author | Van Aert, S.; Verbeeck, J.; Erni, R.; Bals, S.; Luysberg, M.; van Dyck, D.; Van Tendeloo, G. | ||||
Title | Quantitative atomic resolution mapping using high-angle annular dark field scanning transmission electron microscopy | Type | A1 Journal article | ||
Year | 2009 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 109 | Issue | 10 | Pages | 1236-1244 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | A model-based method is proposed to relatively quantify the chemical composition of atomic columns using high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) images. The method is based on a quantification of the total intensity of the scattered electrons for the individual atomic columns using statistical parameter estimation theory. In order to apply this theory, a model is required describing the image contrast of the HAADF STEM images. Therefore, a simple, effective incoherent model has been assumed which takes the probe intensity profile into account. The scattered intensities can then be estimated by fitting this model to an experimental HAADF STEM image. These estimates are used as a performance measure to distinguish between different atomic column types and to identify the nature of unknown columns with good accuracy and precision using statistical hypothesis testing. The reliability of the method is supported by means of simulated HAADF STEM images as well as a combination of experimental images and electron energy-loss spectra. It is experimentally shown that statistically meaningful information on the composition of individual columns can be obtained even if the difference in averaged atomic number Z is only 3. Using this method, quantitative mapping at atomic resolution using HAADF STEM images only has become possible without the need of simultaneously recorded electron energy loss spectra. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000270015200004 | Publication Date | 2009-05-28 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 166 | Open Access | |
Notes | Fwo; Esteem 026019 | Approved | Most recent IF: 2.843; 2009 IF: 2.067 | ||
Call Number | UA @ lucian @ c:irua:78585UA @ admin @ c:irua:78585 | Serial | 2748 | ||
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Author | Verbeeck, J.; Bertoni, G. | ||||
Title | Deconvolution of core electron energy loss spectra | Type | A1 Journal article | ||
Year | 2009 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 109 | Issue | 11 | Pages | 1343-1352 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Different deconvolution methods for removing multiple scattering and instrumental broadening from core loss electron energy loss spectra are compared with special attention to the artefacts they introduce. The Gaussian modifier method, Wiener filter, maximum entropy, and model based methods are described. Their performance is compared on virtual spectra where the true single scattering distribution is known. A test on experimental spectra confirms the good performance of model based deconvolution in comparison to maximum entropy methods and shows the advantage of knowing the estimated error bars from a single spectrum acquisition. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000270765800005 | Publication Date | 2009-07-01 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 13 | Open Access | |
Notes | Fwo; Esteem 026019 | Approved | Most recent IF: 2.843; 2009 IF: 2.067 | ||
Call Number | UA @ lucian @ c:irua:79073UA @ admin @ c:irua:79073 | Serial | 610 | ||
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Author | Van Aert, S.; Chen, J.H.; van Dyck, D. | ||||
Title | Linear versus non-linear structural information limit in high-resolution transmission electron microscopy | Type | A1 Journal article | ||
Year | 2010 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 110 | Issue | 11 | Pages | 1404-1410 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | A widely used performance criterion in high-resolution transmission electron microscopy (HRTEM) is the information limit. It corresponds to the inverse of the maximum spatial object frequency that is linearly transmitted with sufficient intensity from the exit plane of the object to the image plane and is limited due to partial temporal coherence. In practice, the information limit is often measured from a diffractogram or from Young's fringes assuming a weak phase object scattering beyond the inverse of the information limit. However, for an aberration corrected electron microscope, with an information limit in the sub-angstrom range, weak phase objects are no longer applicable since they do not scatter sufficiently in this range. Therefore, one relies on more strongly scattering objects such as crystals of heavy atoms observed along a low index zone axis. In that case, dynamical scattering becomes important such that the non-linear and linear interaction may be equally important. The non-linear interaction may then set the experimental cut-off frequency observed in a diffractogram. The goal of this paper is to quantify both the linear and the non-linear information transfer in terms of closed form analytical expressions. Whereas the cut-off frequency set by the linear transfer can be directly related with the attainable resolution, information from the non-linear transfer can only be extracted using quantitative, model-based methods. In contrast to the historic definition of the information limit depending on microscope parameters only, the expressions derived in this paper explicitly incorporate their dependence on the structure parameters as well. In order to emphasize this dependence and to distinguish from the usual information limit, the expressions derived for the inverse cut-off frequencies will be referred to as the linear and non-linear structural information limit. The present findings confirm the well-known result that partial temporal coherence has different effects on the transfer of the linear and non-linear terms, such that the non-linear imaging contributions are damped less than the linear imaging contributions at high spatial frequencies. This will be important when coherent aberrations such as spherical aberration and defocus are reduced. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000282562100008 | Publication Date | 2010-07-15 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 6 | Open Access | |
Notes | Fwo | Approved | Most recent IF: 2.843; 2010 IF: 2.063 | ||
Call Number | UA @ lucian @ c:irua:83689 | Serial | 1821 | ||
Permanent link to this record | |||||
Author | Ke, X.; Bals, S.; Romo Negreira, A.; Hantschel, T.; Bender, H.; Van Tendeloo, G. | ||||
Title | TEM sample preparation by FIB for carbon nanotube interconnects | Type | A1 Journal article | ||
Year | 2009 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 109 | Issue | 11 | Pages | 1353-1359 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | A powerful method to study carbon nanotubes (CNTs) grown in patterned substrates for potential interconnects applications is transmission electron microscopy (TEM). However, high-quality TEM samples are necessary for such a study. Here, TEM specimen preparation by focused ion beam (FIB) has been used to obtain lamellae of patterned samples containing CNTs grown inside contact holes. A dual-cap Pt protection layer and an extensive 5 kV cleaning procedure are applied in order to preserve the CNTs and avoid deterioration during milling. TEM results show that the inner shell structure of the carbon nanotubes has been preserved, which proves that focused ion beam is a useful technique to prepare TEM samples of CNT interconnects. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000270765800006 | Publication Date | 2009-07-11 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 21 | Open Access | |
Notes | Esteem 026019; Iap | Approved | Most recent IF: 2.843; 2009 IF: 2.067 | ||
Call Number | UA @ lucian @ c:irua:79074 | Serial | 3485 | ||
Permanent link to this record | |||||
Author | Radtke, G.; Botton, G.A.; Verbeeck, J. | ||||
Title | Electron inelastic, scattering and anisotropy: the two-dimensional point of view | Type | A1 Journal article | ||
Year | 2006 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 106 | Issue | 11-12 | Pages | 1082-1090 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | The measurement of the electronic structure of anisotropic materials using energy loss near edge structure (ELNES) spectroscopy is an important field of microanalysis in transmission electron microscopy. We present a novel method to study the angular dependence of electron inelastic scattering in anisotropic materials. This method has been applied to the study of 1s -> pi* and sigma* transitions on the carbon K edge in pyrolitic graphite. An excellent agreement between experimental and theoretical two-dimensional scattering patterns has been found. In particular, the need of a fully relativistic calculation of the inelastic scattering cross-section to explain the experimental results is demonstrated. (c) 2006 Elsevier B.V. All rights reserved. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000241592900018 | Publication Date | 2006-07-04 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 5 | Open Access | |
Notes | Approved | Most recent IF: 2.843; 2006 IF: 1.706 | |||
Call Number | UA @ lucian @ c:irua:61381UA @ admin @ c:irua:61381 | Serial | 936 | ||
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Author | Potapov, P.; Lichte, H.; Verbeeck, J.; van Dyck, D. | ||||
Title | Experiments on inelastic electron holography | Type | A1 Journal article | ||
Year | 2006 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 106 | Issue | 11-12 | Pages | 1012-1018 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | Using the combination of an electron biprism and an energy filter, the coherence distribution in an inelastically scattered wave-field is measured. It is found that the degree of coherence decreases rapidly with increasing distance between two superimposed points in the object, and with increasing energy-loss. In a Si sample, coherence of plasmon scattering increases in vacuum with the distance from the edge of the sample. (c) 2006 Published by Elsevier B.V. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000241592900009 | Publication Date | 2006-07-07 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 28 | Open Access | |
Notes | Approved | Most recent IF: 2.843; 2006 IF: 1.706 | |||
Call Number | UA @ lucian @ c:irua:61380UA @ admin @ c:irua:61380 | Serial | 1147 | ||
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Author | Verbeeck, J.; Van Aert, S.; Bertoni, G. | ||||
Title | Model-based quantification of EELS spectra: including the fine structure | Type | A1 Journal article | ||
Year | 2006 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 106 | Issue | 11-12 | Pages | 976-980 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | An extension to model-based electron energy loss spectroscopy (EELS) quantification is reported to improve the possibility of modelling fine structure changes in electron energy loss spectra. An equalisation function is used in the energy loss near edge structure (ELNES) region to model the differences between a single atom differential cross section and the cross section for an atom in a crystal. The equalisation function can be shown to approximate the relative density of unoccupied states for the given excitation edge. On a set of 200 experimental h-BN spectra, this technique leads to statistically acceptable models resulting into unbiased estimates of relative concentrations and making the estimated precisions come very close to the Cramer-Rao lower bound (CRLB). The method greatly expands the useability of model-based EELS quantification to spectra with pronounced fine structure. Another benefit of this model is that one also gets an estimate of the unoccupied density of states for a given excitation edge, without having to do background removal and deconvolution, making the outcome intrinsically more reliable and less noisy. (c) 2006 Elsevier B.V. All rights reserved. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000241592900004 | Publication Date | 2006-07-04 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 38 | Open Access | |
Notes | Goa; Fwo Iap-V | Approved | Most recent IF: 2.843; 2006 IF: 1.706 | ||
Call Number | UA @ lucian @ c:irua:61379UA @ admin @ c:irua:61379 | Serial | 2102 | ||
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Author | Rosenauer, A.; Schowalter, M.; Titantah, J.T.; Lamoen, D. | ||||
Title | An emission-potential multislice approximation to simulate thermal diffuse scattering in high-resolution transmission electron microscopy | Type | A1 Journal article | ||
Year | 2008 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 108 | Issue | 12 | Pages | 1504-1513 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Thermal diffuse scattered electrons significantly contribute to high-resolution transmission electron microscopy images. Their intensity adds to the background and is peaked at positions of atomic columns. In this paper we suggest an approximation to simulate intensity of thermal diffuse scattered electrons in plane-wave illumination transmission electron microscopy using an emission-potential multislice algorithm which is computationally less intensive than the frozen lattice approximation or the mutual intensity approach. Intensity patterns are computed for Au and InSb for different crystal orientations. These results are compared with intensities from the frozen lattice approximation based on uncorrelated vibration of atoms as well as with the frozen phonon approximation for Au. The frozen phonon method uses a detailed phonon model based on force constants we computed by a density functional theory approach. The comparison shows that our suggested emission-potential method is in close agreement with both the frozen lattice and the frozen phonon approximations. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000260808300002 | Publication Date | 2008-04-21 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 25 | Open Access | |
Notes | Approved | Most recent IF: 2.843; 2008 IF: 2.629 | |||
Call Number | UA @ lucian @ c:irua:72919 | Serial | 1033 | ||
Permanent link to this record | |||||
Author | Croitoru, M.D.; van Dyck, D.; Liu, Y.Z.; Zhang, Z. | ||||
Title | Measurement of specimen thickness by phase change determination in TEM | Type | A1 Journal article | ||
Year | 2008 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 108 | Issue | 12 | Pages | 1616-1622 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | A non-destructive method for measuring the thickness of thin amorphous films composed of light elements has been developed. The method employs the statistics of the phase of the electron exit wave function. The accuracy of this method has been checked numerically by the multislice method and compared with that based on the mean inner potential. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000260808300016 | Publication Date | 2008-06-23 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 2 | Open Access | |
Notes | Approved | Most recent IF: 2.843; 2008 IF: 2.629 | |||
Call Number | UA @ lucian @ c:irua:75643 | Serial | 1961 | ||
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Author | van den Broek, W.; Van Aert, S.; van Dyck, D. | ||||
Title | A model based atomic resolution tomographic algorithm | Type | A1 Journal article | ||
Year | 2009 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 109 | Issue | 12 | Pages | 1485-1490 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | Tomography with high angular annular dark field scanning transmission electron microscopy at atomic resolution can be greatly improved if one is able to take advantage of prior knowledge. In this paper we present a reconstruction technique that explicitly takes into account the microscope parameters and the atomic nature of the projected object. This results in a more accurate estimate of the atomic positions and in a good resistance to noise. The reconstruction is a maximum likelihood estimator of the object. Moreover, the limits to the precision have been explored, allowing for a prediction of the amount of expected noise in the reconstruction for a certain experimental setup. We believe that the proposed reconstruction technique can be generalized to other tomographic experiments. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000271840200010 | Publication Date | 2009-08-28 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 17 | Open Access | |
Notes | Approved | Most recent IF: 2.843; 2009 IF: 2.067 | |||
Call Number | UA @ lucian @ c:irua:78588 | Serial | 2097 | ||
Permanent link to this record | |||||
Author | Van Eyndhoven, G.; Kurttepeli, M.; van Oers, C.J.; Cool, P.; Bals, S.; Batenburg, K.J.; Sijbers, J. | ||||
Title | Pore REconstruction and Segmentation (PORES) method for improved porosity quantification of nanoporous materials | Type | A1 Journal article | ||
Year | 2015 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 148 | Issue | 148 | Pages | 10-19 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab; Laboratory of adsorption and catalysis (LADCA) | ||||
Abstract | Electron tomography is currently a versatile tool to investigate the connection between the structure and properties of nanomaterials. However, a quantitative interpretation of electron tomography results is still far from straightforward. Especially accurate quantification of pore-space is hampered by artifacts introduced in all steps of the processing chain, i.e., acquisition, reconstruction, segmentation and quantification. Furthermore, most common approaches require subjective manual user input. In this paper, the PORES algorithm POre REconstruction and Segmentation is introduced; it is a tailor-made, integral approach, for the reconstruction, segmentation, and quantification of porous nanomaterials. The PORES processing chain starts by calculating a reconstruction with a nanoporous-specific reconstruction algorithm: the Simultaneous Update of Pore Pixels by iterative REconstruction and Simple Segmentation algorithm (SUPPRESS). It classifies the interior region to the pores during reconstruction, while reconstructing the remaining region by reducing the error with respect to the acquired electron microscopy data. The SUPPRESS reconstruction can be directly plugged into the remaining processing chain of the PORES algorithm, resulting in accurate individual pore quantification and full sample pore statistics. The proposed approach was extensively validated on both simulated and experimental data, indicating its ability to generate accurate statistics of nanoporous materials. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000345973000002 | Publication Date | 2014-08-23 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 7 | Open Access | OpenAccess |
Notes | Colouratom; ECAS_Sara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); | Approved | Most recent IF: 2.843; 2015 IF: 2.436 | ||
Call Number | c:irua:119083 | Serial | 2672 | ||
Permanent link to this record | |||||
Author | de Backer, A.; Martinez, G.T.; MacArthur, K.E.; Jones, L.; Béché, A.; Nellist, P.D.; Van Aert, S. | ||||
Title | Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting | Type | A1 Journal article | ||
Year | 2015 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 151 | Issue | 151 | Pages | 56-61 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000351237800008 | Publication Date | 2014-12-03 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 29 | Open Access | |
Notes | 312483 Esteem2; 278510 Vortex; Fwo G039311; G006410; G037413; esteem2ta; ECASJO; | Approved | Most recent IF: 2.843; 2015 IF: 2.436 | ||
Call Number | c:irua:123927 c:irua:123927 | Serial | 753 | ||
Permanent link to this record | |||||
Author | de Backer, A.; De wael, A.; Gonnissen, J.; Van Aert, S. | ||||
Title | Optimal experimental design for nano-particle atom-counting from high-resolution STEM images | Type | A1 Journal article | ||
Year | 2015 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 151 | Issue | 151 | Pages | 46-55 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | In the present paper, the principles of detection theory are used to quantify the probability of error for atom-counting from high resolution scanning transmission electron microscopy (HR STEM) images. Binary and multiple hypothesis testing have been investigated in order to determine the limits to the precision with which the number of atoms in a projected atomic column can be estimated. The probability of error has been calculated when using STEM images, scattering cross-sections or peak intensities as a criterion to count atoms. Based on this analysis, we conclude that scattering cross-sections perform almost equally well as images and perform better than peak intensities. Furthermore, the optimal STEM detector design can be derived for atom-counting using the expression for the probability of error. We show that for very thin objects LAADF is optimal and that for thicker objects the optimal inner detector angle increases. | ||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000351237800007 | Publication Date | 2014-11-11 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 24 | Open Access | |
Notes | 312483 Esteem2; Fwo G039311; G037413; esteem2_jra2 | Approved | Most recent IF: 2.843; 2015 IF: 2.436 | ||
Call Number | c:irua:123926 c:irua:123926 | Serial | 2481 | ||
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Author | Guzzinati, G.; Clark, L.; Béché, A.; Juchtmans, R.; Van Boxem, R.; Mazilu, M.; Verbeeck, J. | ||||
Title | Prospects for versatile phase manipulation in the TEM : beyond aberration correction | Type | A1 Journal article | ||
Year | 2015 | Publication | Ultramicroscopy | Abbreviated Journal | Ultramicroscopy |
Volume | 151 | Issue | 151 | Pages | 85-93 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | In this paper we explore the desirability of a transmission electron microscope in which the phase of the electron wave can be freely controlled. We discuss different existing methods to manipulate the phase of the electron wave and their limitations. We show how with the help of current techniques the electron wave can already be crafted into specific classes of waves each having their own peculiar properties. Assuming a versatile phase modulation device is feasible, we explore possible benefits and methods that could come into existence borrowing from light optics where the so-called spatial light modulators provide programmable phase plates for quite some time now. We demonstrate that a fully controllable phase plate building on Harald Rose׳s legacy in aberration correction and electron optics in general would open an exciting field of research and applications. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Amsterdam | Editor | ||
Language | Wos | 000351237800012 | Publication Date | 2014-10-22 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0304-3991; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.843 | Times cited | 19 | Open Access | |
Notes | 278510 Vortex; Fwo; 312483 Esteem2; esteem2jra2; esteem2jra3 ECASJO_; | Approved | Most recent IF: 2.843; 2015 IF: 2.436 | ||
Call Number | c:irua:121405 c:irua:121405UA @ admin @ c:irua:121405 | Serial | 2731 | ||
Permanent link to this record |