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Author Zhuge, X.; Jinnai, H.; Dunin-Borkowski, R.E.; Migunov, V.; Bals, S.; Cool, P.; Bons, A.-J.; Batenburg, K.J. pdf  url
doi  openurl
  Title Automated discrete electron tomography – Towards routine high-fidelity reconstruction of nanomaterials Type A1 Journal article
  Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 175 Issue 175 Pages 87-96  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)  
  Abstract Electron tomography is an essential imaging technique for the investigation of morphology and 3D structure of nanomaterials. This method, however, suffers from well-known missing wedge artifacts due to a restricted tilt range, which limits the objectiveness, repeatability and efficiency of quantitative structural analysis. Discrete tomography represents one of the promising reconstruction techniques for materials science, potentially capable of delivering higher fidelity reconstructions by exploiting the prior knowledge of the limited number of material compositions in a specimen. However, the application of discrete tomography to practical datasets remains a difficult task due to the underlying challenging mathematical problem. In practice, it is often hard to obtain consistent reconstructions from experimental datasets. In addition, numerous parameters need to be tuned manually, which can lead to bias and non-repeatability. In this paper, we present the application of a new

iterative reconstruction technique, named TVR-DART, for discrete electron tomography. The technique is capable of consistently delivering reconstructions with significantly reduced missing wedge artifacts for a variety of challenging data and imaging conditions, and can automatically estimate its key parameters. We describe the principles of the technique and apply it to datasets from three different types of samples acquired under diverse imaging modes. By further reducing the available tilt range and number of projections, we show that the

proposed technique can still produce consistent reconstructions with minimized missing wedge artifacts. This new development promises to provide the electron microscopy community with an easy-to-use and robust tool for high-fidelity 3D characterization of nanomaterials.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000403342500008 Publication Date 2017-01-24  
  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 (up) 2.843 Times cited 22 Open Access OpenAccess  
  Notes This work has been supported in part by the Stichting voor de Technische Wetenschappen (STW) through a personal grant (Veni,13610), and was in part by ExxonMobil Chemical Europe Inc. The authors further acknowledge financial support from the University of Antwerp through BOF GOA funding. S.B. acknowledges financial support from the European Research Council (ERC Starting Grant #335078-COLOURATOMS). R.D.B. is grateful for funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007–2013)/ ERC grant agreement number 320832. Thomas Altantzis is gratefully acknowledged for acquiring the Anatase nanosheets dataset. (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); saraecas; ECAS_Sara; Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @ c:irua:141218UA @ admin @ c:irua:141218 Serial 4485  
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Author Béché, A.; Rouvière, J.L.; Barnes, J.P.; Cooper, D. doi  openurl
  Title Dark field electron holography for strain measurement Type A1 Journal article
  Year 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 111 Issue 3 Pages 227-238  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Dark field electron holography is a new TEM-based technique for measuring strain with nanometer scale resolution. Here we present the procedure to align a transmission electron microscope and obtain dark field holograms as well as the theoretical background necessary to reconstruct strain maps from holograms. A series of experimental parameters such as biprism voltage, sample thickness, exposure time, tilt angle and choice of diffracted beam are then investigated on a silicon-germanium layer epitaxially embedded in a silicon matrix in order to obtain optimal dark field holograms over a large field of view with good spatial resolution and strain sensitivity.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000288638200007 Publication Date 2010-12-01  
  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 (up) 2.843 Times cited 31 Open Access  
  Notes Approved Most recent IF: 2.843; 2011 IF: 2.471  
  Call Number UA @ lucian @ c:irua:136368 Serial 4496  
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Author Stefan Löffler; Matthieu Bugnet; Nicolas Gauquelin; Sorin Lazar; Elias Assmann; Karsten Held; Gianluigi A. Botton; Peter Schattschneider pdf  doi
openurl 
  Title Real-space mapping of electronic orbitals Type A1 Journal article
  Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 177 Issue 177 Pages 26-29  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Electronic states are responsible for most material properties, including chemical bonds, electrical and thermal conductivity, as well as optical and magnetic properties. Experimentally, however, they remain mostly elusive. Here, we report the real-space mapping of selected transitions between p and d states on the Ångström scale in bulk rutile (TiO2) using electron energy-loss spectrometry (EELS), revealing information on individual bonds between atoms. On the one hand, this enables the experimental verification of theoretical predictions about electronic states. On the other hand, it paves the way for directly investigating electronic states under conditions that are at the limit of the current capabilities of numerical simulations such as, e.g., the electronic states at defects, interfaces, and quantum dots.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000401219800004 Publication Date 2017-01-31  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record  
  Impact Factor (up) 2.843 Times cited Open Access Not_Open_Access  
  Notes ; St.L. thanks Walid Hetaba for discussions about WIEN2k. St.L. and P.S. thank Ralf Hambach and Ute Kaiser for many valuable discussions. M.B. thanks Vienna University of Technology for travel support. St.L. and P.S. acknowledge financial support by the Austrian Science Fund (FWF) under grant number 1543-N20, SFB F45 FOXSI; St.L. also acknowledges financial support by the Austrian Science Fund (FWF) under grant number J3732-N27. M.B., N.G., S.L. and G.A.B. performed the experimental work at the Canadian Center for Electron Microscopy, a national facility supported by McMaster University and the Natural Sciences and Engineering Research Council of Canada (NSERC). G.A.B. is grateful to NSERC for supporting this work. ; Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @ c:irua:142201 Serial 4539  
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Author Alania, M.; De Backer, A.; Lobato, I.; Krause, F.F.; Van Dyck, D.; Rosenauer, A.; Van Aert, S. pdf  url
doi  openurl
  Title How precise can atoms of a nanocluster be located in 3D using a tilt series of scanning transmission electron microscopy images? Type A1 Journal article
  Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 181 Issue 181 Pages 134-143  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract In this paper, we investigate how precise atoms of a small nanocluster can ultimately be located in three dimensions (3D) from a tilt series of images acquired using annular dark field (ADF) scanning transmission electron microscopy (STEM). Therefore, we derive an expression for the statistical precision with which the 3D atomic position coordinates can be estimated in a quantitative analysis. Evaluating this statistical precision as a function of the microscope settings also allows us to derive the optimal experimental design. In this manner, the optimal angular tilt range, required electron dose, optimal detector angles, and number of projection images can be determined.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000411170800016 Publication Date 2016-12-15  
  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 (up) 2.843 Times cited 3 Open Access OpenAccess  
  Notes The authors acknowledge financial support from the European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure Initiative. Reference No. 312483-ESTEEM2. The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0374.13N, G.0369.15N, G.0368.15N, and WO.010.16N) and a post-doctoral grant to A. De Backer, and from the DFG under contract No. RO-2057/4-2. Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @ c:irua:144432 Serial 4618  
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Author Gauquelin, N.; van den Bos, K.H.W.; Béché, A.; Krause, F.F.; Lobato, I.; Lazar, S.; Rosenauer, A.; Van Aert, S.; Verbeeck, J. pdf  url
doi  openurl
  Title Determining oxygen relaxations at an interface: A comparative study between transmission electron microscopy techniques Type A1 Journal article
  Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 181 Issue 181 Pages 178-190  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Nowadays, aberration corrected transmission electron microscopy (TEM) is a popular method to characterise nanomaterials at the atomic scale. Here, atomically resolved images of nanomaterials are acquired, where the contrast depends on the illumination, imaging and detector conditions of the microscope. Visualization of light elements is possible when using low angle annular dark field (LAADF) STEM, annular bright field (ABF) STEM, integrated differential phase contrast (iDPC) STEM, negative spherical aberration imaging (NCSI) and imaging STEM (ISTEM). In this work, images of a NdGaO3-La0.67Sr0.33MnO3 (NGO-LSMO) interface are quantitatively evaluated by using statistical parameter estimation theory. For imaging light elements, all techniques are providing reliable results, while the techniques based on interference contrast, NCSI and ISTEM, are less robust in terms of accuracy for extracting heavy column locations. In term of precision, sample drift and scan distortions mainly limits the STEM based techniques as compared to NCSI. Post processing techniques can, however, partially compensate for this. In order to provide an outlook to the future, simulated images of NGO, in which the unavoidable presence of Poisson noise is taken into account, are used to determine the ultimate precision. In this future counting noise limited scenario, NCSI and ISTEM imaging will provide more precise values as compared to the other techniques, which can be related to the mechanisms behind the image recording.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000411170800022 Publication Date 2017-06-03  
  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 (up) 2.843 Times cited 34 Open Access OpenAccess  
  Notes The authors acknowledge financial support from Flanders (FWO, Belgium) through project fundings (G.0044.13N, G.0374.13N, G.0368.15N, G.0369.15N), and by a Ph.D. grant to K.H.W.v.d.B. The Qu-Ant-EM microscope used for this study was partly funded by the Hercules fund from the Flemish Government. A.B. and N.G. acknowledge the EUROTAPES project (FP7-NMP.2011.2.2-1 Grant no.280432) which partly funded this study. N.G., A.B. and J.V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. The research leading to these results has received funding from the Deutsche Forschungsgemeinschaft under Contract No. RO 2057/4-2 and the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2. We thank Prof. G. Koster from the University of Twente for kindly providing us with the LSMO-NGO test sample. Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @ c:irua:144435UA @ admin @ c:irua:144435 Serial 4620  
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Author De wael, A.; De Backer, A.; Jones, L.; Nellist, P.D.; Van Aert, S. pdf  url
doi  openurl
  Title Hybrid statistics-simulations based method for atom-counting from ADF STEM images Type A1 Journal article
  Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 177 Issue 177 Pages 69-77  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract A hybrid statistics-simulations based method for atom-counting from annular dark field scanning transmission electron microscopy (ADF STEM) images of monotype crystalline nanostructures is presented. Different atom-counting methods already exist for model-like systems. However, the increasing relevance of radiation damage in the study of nanostructures demands a method that allows atom-counting from low dose images with a low signal-to-noise ratio. Therefore, the hybrid method directly includes prior knowledge from image simulations into the existing statistics-based method for atom-counting, and accounts in this manner for possible discrepancies between actual and simulated experimental conditions. It is shown by means of simulations and experiments that this hybrid method outperforms the statistics-based method, especially for low electron doses and small nanoparticles. The analysis of a simulated low dose image of a small nanoparticle suggests that this method allows for far more reliable quantitative analysis of beam-sensitive materials.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000401219800010 Publication Date 2017-01-25  
  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 (up) 2.843 Times cited 8 Open Access OpenAccess  
  Notes The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0374.13N, G.0368.15N, G.0369.15N, and WO.010.16N), and a postdoctoral research Grant to A. De Backer. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2 (Integrated Infrastructure Initiative-I3). The authors are grateful to G.T. Martinez for providing image simulations. Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @ c:irua:141718 Serial 4486  
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Author Vatanparast, M.; Egoavil, R.; Reenaas, T.W.; Verbeeck, J.; Holmestad, R.; Vullum, P.E. pdf  doi
openurl 
  Title Bandgap measurement of high refractive index materials by off-axis EELS Type A1 Journal article
  Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 182 Issue Pages 92-98  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract In the present work Cs aberration corrected and monochromated scanning transmission electron microscopy electron energy loss spectroscopy (STEM-EELS) has been used to explore experimental setups that allow bandgaps of high refractive index materials to be determined. Semi-convergence and collection angles in the mu rad range were combined with off-axis or dark field EELS to avoid relativistic losses and guided light modes in the low loss range to contribute to the acquired EEL spectra. Off-axis EELS further supressed the zero loss peak and the tail of the zero loss peak. The bandgap of several GaAs-based materials were successfully determined by simple regression analyses of the background subtracted EEL spectra. The presented set-up does not require that the acceleration voltage is set to below the. Cerenkov limit and can be applied over the entire acceleration voltage range of modern TEMs and for a wide range of specimen thicknesses. (C) 2017 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000413436500013 Publication Date 2017-06-21  
  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 (up) 2.843 Times cited 3 Open Access Not_Open_Access  
  Notes ; The authors would like to thank Professor Shu Min Wang and Mahdad Sadeghi at the Nanofabrication Laboratory at Chalmers University, Sweden for providing the samples. The Norwegian Research Council is acknowledged for funding the HighQ-IB project under contract no. 10415201. M.V. and T.W.R. acknowledge funding from the EEA Financial Mechanism 2009-2014 under the project contract no 23SEE/30.06.2014. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483 – ESTEEM2(Integrated Infrastructure Initiative-I3) through the system of transnational access. R.E. and J.V. acknowledge funding from GOA project “Solarpaint” of the University of Antwerp. ; Approved Most recent IF: 2.843  
  Call Number UA @ lucian @ c:irua:146639UA @ admin @ c:irua:146639 Serial 4778  
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Author Grieb, T.; Krause, F.F.; Mahr, C.; Zillmann, D.; Müller-Caspary, K.; Schowalter, M.; Rosenauer, A. pdf  doi
openurl 
  Title Optimization of NBED simulations for disc-detection measurements Type A1 Journal article
  Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 181 Issue Pages 50-60  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Nano-beam electron diffraction (NBED) is a method which can be applied to measure lattice strain and polarisation fields in strained layer heterostructures and transistors. To investigate precision, accuracy and spatial resolution of such measurements in dependence of properties of the specimen as well as electron optical parameters, simulations of NBED patterns are required which allow to predict the result of common disc-detection algorithms. In this paper we demonstrate by focusing on the detection of the central disc in crystalline silicon that such simulations require to take several experimental characteristics into account in order to obtain results which are comparable to those from experimental NBED patterns. These experimental characteristics are the background intensity, the presence of Poisson noise caused by electron statistics and blurring caused by inelastic scattering and by the transfer quality of the microscope camera. By means of these optimized simulations, different effects of specimen properties on disc detection – such as strain, surface morphology and compositional changes on the nanometer scale – are investigated and discussed in the context of misinterpretation in experimental NBED evaluations. It is shown that changes in surface morphology and chemical composition lead to measured shifts of the central disc in the NBED pattern of tens to hundreds of grad. These shifts are of the same order of magnitude or even larger than shifts that could be caused by an electric polarisation field in the range of MV/cm. (C) 2017 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000411170800006 Publication Date 2017-05-03  
  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 (up) 2.843 Times cited 6 Open Access Not_Open_Access  
  Notes ; This work was supported by the German Research Foundation (DFG) under Contract No. R02057/11-1, R02057/4-2 and MU3660/1-1. ; Approved Most recent IF: 2.843  
  Call Number UA @ lucian @ c:irua:146725 Serial 4792  
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Author Zhong, Z.; Aveyard, R.; Rieger, B.; Bals, S.; Palenstijn, W.J.; Batenburg, K.J. pdf  url
doi  openurl
  Title Automatic correction of nonlinear damping effects in HAADF-STEM tomography for nanomaterials of discrete compositions Type A1 Journal article
  Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 184 Issue 184 Pages 57-65  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract <script type='text/javascript'>document.write(unpmarked('HAADF-STEM tomography is a common technique for characterizing the three-dimensional morphology of nanomaterials. In conventional tomographic reconstruction algorithms, the image intensity is assumed to be a linear projection of a physical property of the specimen. However, this assumption of linearity is not completely valid due to the nonlinear damping of signal intensities. The nonlinear damping effects increase w.r.t the specimen thickness and lead to so-called \u0022cupping artifacts\u0022, due to a mismatch with the linear model used in the reconstruction algorithm. Moreover, nonlinear damping effects can strongly limit the applicability of advanced reconstruction approaches such as Total Variation Minimization and discrete tomography. In this paper, we propose an algorithm for automatically correcting the nonlinear effects and the subsequent cupping artifacts. It is applicable to samples in which chemical compositions can be segmented based on image gray levels. The correction is realized by iteratively estimating the nonlinear relationship between projection intensity and sample thickness, based on which the projections are linearized. The correction and reconstruction algorithms are tested on simulated and experimental data. (C) 2017 Elsevier B.V. All rights reserved.'));  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000417779800008 Publication Date 2017-10-31  
  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 (up) 2.843 Times cited 8 Open Access OpenAccess  
  Notes ; This research is supported by the Dutch Technology Foundation STW (http:// www.stw.nl/), which is part of the Netherlands Organization for Scientific Research (NWO), and which is partly funded by the Ministry of Economic Affairs, Agriculture and Innovation under project number 13314. Funding from the European Research Council (Starting grant no. COLOURATOMS 335078) is acknowledged by S. Bals. The authors would like to thank Dr. Thomas Altantzis and Dr. Bart Goris for providing the experimental data, and Prof. Dr. Luis M. Liz-Marzan for providing the investigated samples. ; ecas_sara Approved Most recent IF: 2.843  
  Call Number UA @ lucian @ c:irua:148501UA @ admin @ c:irua:148501 Serial 4867  
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Author Alania, M.; Lobato Hoyos, I.P.; Van Aert, S. pdf  url
doi  openurl
  Title Frozen lattice and absorptive model for high angle annular dark field scanning transmission electron microscopy : a comparison study in terms of integrated intensity and atomic column position measurement Type A1 Journal article
  Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 184 Issue A Pages 188-198  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract <script type='text/javascript'>document.write(unpmarked('In this paper, both the frozen lattice (FL) and the absorptive potential (AP) approximation models are compared in terms of the integrated intensity and the precision with which atomic columns can be located from an image acquired using high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM). The comparison is made for atoms of Cu, Ag, and Au. The integrated intensity is computed for both an isolated atomic column and an atomic column inside an FCC structure. The precision has been computed using the so-called Cramer-Rao Lower Bound (CRLB), which provides a theoretical lower bound on the variance with which parameters can be estimated. It is shown that the AP model results into accurate measurements for the integrated intensity only for small detector ranges under relatively low angles and for small thicknesses. In terms of the attainable precision, both methods show similar results indicating picometer range precision under realistic experimental conditions. (C) 2017 Elsevier B.V. All rights reserved.'));  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000415650200022 Publication Date 2017-09-12  
  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 (up) 2.843 Times cited Open Access OpenAccess  
  Notes ; The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0374.13N, G.0369.15N, and G.0368.15N). A. Rosenauer is acknowledged for providing the STEMsim program. ; Approved Most recent IF: 2.843  
  Call Number UA @ lucian @ c:irua:147658 Serial 4877  
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Author Grieb, T.; Tewes, M.; Schowalter, M.; Müller-Caspary, K.; Krause, F.F.; Mehrtens, T.; Hartmann, J.-M.; Rosenauer, A. pdf  doi
openurl 
  Title Quantitative HAADF STEM of SiGe in presence of amorphous surface layers from FIB preparation Type A1 Journal article
  Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 184 Issue B Pages 29-36  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract <script type='text/javascript'>document.write(unpmarked('The chemical composition of four Si1-xGex layers grown on silicon was determined from quantitative scanning transmission electron microscopy (STEM). The chemical analysis was performed by a comparison of the high-angle annular dark field (HAADF) intensity with multislice simulations. It could be shown that amorphous surface layers originating from the preparation process by focused-ion beam (FIB) at 30 kV have a strong influence on the quantification: the local specimen thickness is overestimated by approximately a factor of two, and the germanium concentration is substantially underestimated. By means of simulations, the effect of amorphous surface layers on the HAADF intensity of crystalline silicon and germanium is investigated. Based on these simulations, a method is developed to analyze the experimental HAADF-STEM images by taking the influence of the amorphous layers into account which is done by a reduction of the intensities by multiplication with a constant factor. This suggested modified HAADF analysis gives germanium concentrations which are in agreement with the nominal values. The same TEM lamella was treated with low-voltage ion milling which removed the amorphous surface layers completely. The results from subsequent quantitative HAADF analyses are in agreement with the nominal concentrations which validates the applicability of the used frozen-lattice based multislice simulations to describe the HAADF scattering of Si1-xGex in STEM. (C) 2017 Elsevier B.V. All rights reserved.'));  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000417779800004 Publication Date 2017-10-14  
  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 (up) 2.843 Times cited 7 Open Access Not_Open_Access  
  Notes ; This work was supported by the German Research Foundation (DFG) under Contract No. RO2057/11-1. ; Approved Most recent IF: 2.843  
  Call Number UA @ lucian @ c:irua:148500 Serial 4893  
Permanent link to this record
 

 
Author Schryvers, D.; Salje, E.K.H.; Nishida, M.; De Backer, A.; Idrissi, H.; Van Aert, S. pdf  url
doi  openurl
  Title Quantification by aberration corrected (S)TEM of boundaries formed by symmetry breaking phase transformations Type A1 Journal article
  Year 2017 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 176 Issue Pages 194-199  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The present contribution gives a review of recent quantification work of atom displacements, atom site occupations and level of crystallinity in various systems and based on aberration corrected HR(S)TEM images. Depending on the case studied, picometer range precisions for individual distances can be obtained, boundary widths at the unit cell level determined or statistical evolutions of fractions of the ordered areas calculated. In all of these cases, these quantitative measures imply new routes for the applications of the respective materials.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000403992200026 Publication Date 2017-01-09  
  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 (up) 2.843 Times cited 1 Open Access OpenAccess  
  Notes The authors acknowledge financial support from the Fund for Scientific Research-Flanders (G.0064.10N, G.0393.11N, G.0374.13N, G.0368.15N, G.0369.15N) and the Flemish Hercules 3 program for large infrastructure as well as financial support from the European Union Seventh Framework Programme (FP7/2007 – 2013) under Grant agreement no. 312483 (ESTEEM2). EKHS thanks EPSRC (EP/ K009702/1) and the Leverhulme trust (EM-2016-004) for support. DS and MN acknowledge financial support from the Japan Society for the Promotion of Science (JSPS, Japan) through the Grant-in-Aid for Scientific Research (A: No. 26249090) and the Strategic Young Researcher Overseas Visits Program for Accelerating Brain Circulation (R2408). Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @c:irua:149654 Serial 4914  
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Author Verbeeck, J.; Béché, A.; Müller-Caspary, K.; Guzzinati, G.; Luong, M.A.; Den Hertog, M. pdf  url
doi  openurl
  Title Demonstration of a 2 × 2 programmable phase plate for electrons Type A1 Journal article
  Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 190 Issue Pages 58-65  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract First results on the experimental realisation of a 2 × 2 programmable phase plate for electrons are presented. The design consists of an array of electrostatic elements that influence the phase of electron waves passing through 4 separately controllable aperture holes. This functionality is demonstrated in a conventional transmission electron microscope operating at 300 kV and results are in very close agreement with theoretical predictions. The dynamic creation of a set of electron probes with different phase symmetry is demonstrated, thereby bringing adaptive optics in TEM one step closer to reality. The limitations of the current design and how to overcome these in the future are discussed. Simulations show how further evolved versions of the current proof of concept might open new and exciting application prospects for beam shaping and aberration correction.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000432868800007 Publication Date 2018-04-18  
  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 (up) 2.843 Times cited 73 Open Access Not_Open_Access: Available from 19.04.2020  
  Notes J.V. and A.B. acknowledge funding from the Fund for Scientific Research Flanders FWO project G093417N and the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX and ERC proof of concept project DLV-789598 ADAPTEM. The Qu-Ant-EM microscope used in this work was partly funded by the Hercules fund from the Flemish Government. MdH acknowledges financial support from the ANRCOSMOS (ANR-12-JS10-0002). MdH and ML acknowledge funding from the Laboratoire d’excellence LANEF in Grenoble (ANR-10-LABX-51-01). Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @c:irua:150459UA @ admin @ c:irua:150459 Serial 4920  
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Author Korneychuk, S.; Partoens, B.; Guzzinati, G.; Ramaneti, R.; Derluyn, J.; Haenen, K.; Verbeeck, J. pdf  url
doi  openurl
  Title Exploring possibilities of band gap measurement with off-axis EELS in TEM Type A1 Journal article
  Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 189 Issue 189 Pages 76-84  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract A technique to measure the band gap of dielectric materials with high refractive index by means of energy electron loss spectroscopy (EELS) is presented. The technique relies on the use of a circular (Bessel) aperture and suppresses Cherenkov losses and surface-guided light modes by enforcing a momentum transfer selection. The technique also strongly suppresses the elastic zero loss peak, making the acquisition, interpretation and signal to noise ratio of low loss spectra considerably better, especially for excitations in the first few eV of the EELS spectrum. Simulations of the low loss inelastic electron scattering probabilities demonstrate the beneficial influence of the Bessel aperture in this setup even for high accelerating voltages. The importance of selecting the optimal experimental convergence and collection angles is highlighted. The effect of the created off-axis acquisition conditions on the selection of the transitions from valence to conduction bands is discussed in detail on a simplified isotropic two band model. This opens the opportunity for deliberately selecting certain transitions by carefully tuning the microscope parameters. The suggested approach is experimentally demonstrated and provides good signal to noise ratio and interpretable band gap signals on reference samples of diamond, GaN and AlN while offering spatial resolution in the nm range. (C) 2018 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000432868500008 Publication Date 2018-03-29  
  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 (up) 2.843 Times cited 7 Open Access OpenAccess  
  Notes ; S.K., B.P. and J.V. acknowledge funding from the “Geconcentreerde Onderzoekacties” (GOA) project “Solarpaint” of the University of Antwerp. S.K. and J.V. also acknowledge the FWO-Vlaanderen for financial support under contract G.0044.13N 'Charge ordering'. Financial support via the Methusalem “NANO” network is acknowledged. GG acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek-Vlaanderen (FWO). ; Approved Most recent IF: 2.843  
  Call Number UA @ lucian @ c:irua:151472UA @ admin @ c:irua:151472 Serial 5026  
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Author Grieb, T.; Krause, F.F.; Schowalter, M.; Zillmann, D.; Sellin, R.; Müller-Caspary, K.; Mahr, C.; Mehrtens, T.; Bimberg, D.; Rosenauer, A. pdf  url
doi  openurl
  Title Strain analysis from nano-beam electron diffraction : influence of specimen tilt and beam convergence Type A1 Journal article
  Year 2018 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 190 Issue 190 Pages 45-57  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Strain analyses from experimental series of nano-beam electron diffraction (NBED) patterns in scanning transmission electron microscopy are performed for different specimen tilts. Simulations of NBED series are presented for which strain analysis gives results that are in accordance with experiment. This consequently allows to study the relation between measured strain and actual underlying strain. A two-tilt method which can be seen as lowest-order electron beam precession is suggested and experimentally implemented. Strain determination from NBED series with increasing beam convergence is performed in combination with the experimental realization of a probe-forming aperture with a cross inside. It is shown that using standard evaluation techniques, the influence of beam convergence on spatial resolution is lower than the influence of sharp rings around the diffraction disc which occur at interfaces and which are caused by the tails of the intensity distribution of the electron probe. (C) 2018 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000432868800006 Publication Date 2018-04-12  
  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 (up) 2.843 Times cited 1 Open Access OpenAccess  
  Notes ; This work was supported by the German Research Foundation (DFG) under Contracts RO2057/11-1 and RO2057/12-1. ; Approved Most recent IF: 2.843  
  Call Number UA @ lucian @ c:irua:151454 Serial 5041  
Permanent link to this record
 

 
Author van den Bos, K.H.W.; Janssens, L.; De Backer, A.; Nellist, P.D.; Van Aert, S. url  doi
openurl 
  Title The atomic lensing model: new opportunities for atom-by-atom metrology of heterogeneous nanomaterials Type A1 Journal article
  Year 2019 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 203 Issue Pages 155  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The atomic lensing model has been proposed as a promising method facilitating atom-counting in heterogeneous nanocrystals [1]. Here, image simulations will validate the model, which describes dynamical diffraction as a superposition of individual atoms focussing the incident electrons. It will be demonstrated that the model is reliable in the annular dark field regime for crystals having columns containing dozens of atoms. By using the principles of statistical detection theory, it will be shown that this model gives new opportunities for detecting compositional differences.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000465021000020 Publication Date 2018-12-06  
  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 (up) 2.843 Times cited 4 Open Access OpenAccess  
  Notes The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0369.15N, G.0502.18N and WO.010.16N), and by personal grants to K.H.W. van den Bos and A. De Backer. This project has received funding from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme (grant agreement No. 770887). Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @UA @ admin @ c:irua:155721 Serial 5074  
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Author Fatermans, J.; Van Aert, S.; den Dekker, A.J. url  doi
openurl 
  Title The maximum a posteriori probability rule for atom column detection from HAADF STEM images Type A1 Journal article
  Year 2019 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 201 Issue Pages 81-91  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract Recently, the maximum a posteriori (MAP) probability rule has been proposed as an objective and quantitative method to detect atom columns and even single atoms from high-resolution high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) images. The method combines statistical parameter estimation and model-order selection using a Bayesian framework and has been shown to be especially useful for the analysis of the structure of beam-sensitive nanomaterials. In order to avoid beam damage, images of such materials are usually acquired using a limited incoming electron dose resulting in a low contrast-to-noise ratio (CNR) which makes visual inspection unreliable. This creates a need for an objective and quantitative approach. The present paper describes the methodology of the MAP probability rule, gives its step-by-step derivation and discusses its algorithmic implementation for atom column detection. In addition, simulation results are presented showing that the performance of the MAP probability rule to detect the correct number of atomic columns from HAADF STEM images is superior to that of other model-order selection criteria, including the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC). Moreover, the MAP probability rule is used as a tool to evaluate the relation between STEM image quality measures and atom detectability resulting in the introduction of the so-called integrated CNR (ICNR) as a new image quality measure that better correlates with atom detectability than conventional measures such as signal-to-noise ratio (SNR) and CNR.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000466343800009 Publication Date 2019-02-04  
  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 (up) 2.843 Times cited 1 Open Access OpenAccess  
  Notes The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (No. W.O.010.16N, No. G.0368.15N, No. G.0502.18N). This project has received funding from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme (Grant Agreement No. 770887). Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @UA @ admin @ c:irua:157176 Serial 5153  
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Author Müller-Caspary, K.; Krause, F.F.; Winkler, F.; Béché, A.; Verbeeck, J.; Van Aert, S.; Rosenauer, A. pdf  url
doi  openurl
  Title Comparison of first moment STEM with conventional differential phase contrast and the dependence on electron dose Type A1 Journal article
  Year 2019 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 203 Issue 203 Pages 95-104  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract This study addresses the comparison of scanning transmission electron microscopy (STEM) measurements of momentum transfers using the first moment approach and the established method that uses segmented annular detectors. Using an ultrafast pixelated detector to acquire four-dimensional, momentum-resolved STEM signals, both the first moment calculation and the calculation of the differential phase contrast (DPC) signals are done for the same experimental data. In particular, we investigate the ability to correct the segment-based signal to yield a suitable approximation of the first moment for cases beyond the weak phase object approximation. It is found that the measurement of momentum transfers using segmented detectors can approach the first moment measurement as close as 0.13 h/nm in terms of a root mean square (rms) difference in 10 nm thick SrTiO3 for a detector with 16 segments. This amounts to 35% of the rms of the momentum transfers. In addition, we present a statistical analysis of the precision of first moment STEM as a function of dose. For typical experimental settings with recent hardware such as a Medipix3 Merlin camera attached to a probe-corrected STEM, we find that the precision of the measurement of momentum transfers stagnates above certain doses. This means that other instabilities such as specimen drift or scan noise have to be taken into account seriously for measurements that target, e.g., the detection of bonding effects in the charge density.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000465021000013 Publication Date 2018-12-30  
  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 (up) 2.843 Times cited 25 Open Access OpenAccess  
  Notes ; The direct electron detector (Medipix3 Merlin) was funded by the Hercules fund from the Flemish Government. K. Muller-Caspary acknowledges funding from the Initiative and Network Fund of the Helmholtz Association within the framework of the Helmholtz Young Investigator Group moreSTEM (VH-NG-1317) at Forschungszentrum Julich, Germany. F. F. Krause acknowledges funding from the Central Research Development Fund of the University of Bremen, Germany. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 770887). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) and the Research Fund of the University of Antwerp. ; Approved Most recent IF: 2.843  
  Call Number UA @ admin @ c:irua:160213 Serial 5242  
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Author Susi, T.; Madsen, J.; Ludacka, U.; Mortensen, J.J.; Pennycook, T.J.; Lee, Z.; Kotakoski, J.; Kaiser, U.; Meyer, J.C. doi  openurl
  Title Efficient first principles simulation of electron scattering factors for transmission electron microscopy Type A1 Journal article
  Year 2019 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 197 Issue 197 Pages 16-22  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Electron microscopy is a powerful tool for studying the properties of materials down to their atomic structure. In many cases, the quantitative interpretation of images requires simulations based on atomistic structure models. These typically use the independent atom approximation that neglects bonding effects, which may, however, be measurable and of physical interest. Since all electrons and the nuclear cores contribute to the scattering potential, simulations that go beyond this approximation have relied on computationally highly demanding all-electron calculations. Here, we describe a new method to generate ab initio electrostatic potentials when describing the core electrons by projector functions. Combined with an interface to quantitative image simulations, this implementation enables an easy and fast means to model electron scattering. We compare simulated transmission electron microscopy images and diffraction patterns to experimental data, showing an accuracy equivalent to earlier all-electron calculations at a much lower computational cost.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000456311700003 Publication Date 2018-11-12  
  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 (up) 2.843 Times cited 3 Open Access  
  Notes Approved Most recent IF: 2.843  
  Call Number UA @ admin @ c:irua:165938 Serial 6296  
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Author Pennycook, T.J.; Martinez, G.T.; Nellist, P.D.; Meyer, J.C. doi  openurl
  Title High dose efficiency atomic resolution imaging via electron ptychography Type A1 Journal article
  Year 2019 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 196 Issue 196 Pages 131-135  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Radiation damage places a fundamental limitation on the ability of microscopy to resolve many types of materials at high resolution. Here we evaluate the dose efficiency of phase contrast imaging with electron ptychography. The method is found to be far more resilient to temporal incoherence than conventional and spherical aberration optimized phase contrast imaging, resulting in significantly greater clarity at a given dose. This robustness is explained by the presence of achromatic lines in the four dimensional ptychographic dataset.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000451180800018 Publication Date 2018-10-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor (up) 2.843 Times cited 1 Open Access  
  Notes Approved Most recent IF: 2.843  
  Call Number UA @ admin @ c:irua:165939 Serial 6301  
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Author Leuthner, G.T.; Hummel, S.; Mangler, C.; Pennycook, T.J.; Susi, T.; Meyer, J.C.; Kotakoski, J. pdf  doi
openurl 
  Title Scanning transmission electron microscopy under controlled low-pressure atmospheres Type A1 Journal article
  Year 2019 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 203 Issue 203 Pages 76-81  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Transmission electron microscopy (TEM) is carried out in vacuum to minimize the interaction of the imaging electrons with gas molecules while passing through the microscope column. Nevertheless, in typical devices, the pressure remains at 10(-7) mbar or above, providing a large number of gas molecules for the electron beam to crack, which can lead to structural changes in the sample. Here, we describe experiments carried out in a modified scanning TEM (STEM) instrument, based on the Nion UltraSTEM 100. In this instrument, the base pressure at the sample is around 2 x 10(-10 )mbar, and can be varied up to 10(-6) mbar through introduction of gases directly into the objective area while maintaining atomic resolution imaging conditions. We show that air leaked into the microscope column during the experiment is efficient in cleaning graphene samples from contamination, but ineffective in damaging the pristine lattice. Our experiments also show that exposure to O(2 )and H2O lead to a similar result, oxygen providing an etching effect nearly twice as efficient as water, presumably due to the two 0 atoms per molecule. H(2 )and N-2 environments have no influence on etching. These results show that the residual gas environment in typical TEM instruments can have a large influence on the observations, and show that chemical etching of carbon-based structures can be effectively carried out with oxygen.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000465021000010 Publication Date 2019-02-04  
  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 (up) 2.843 Times cited 4 Open Access  
  Notes Approved Most recent IF: 2.843  
  Call Number UA @ admin @ c:irua:165937 Serial 6321  
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Author Vanrompay, H.; Skorikov, A.; Bladt, E.; Béché, A.; Freitag, B.; Verbeeck, J.; Bals, S. url  doi
openurl 
  Title Fast versus conventional HAADF-STEM tomography of nanoparticles: advantages and challenges Type A1 Journal article
  Year 2021 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 221 Issue Pages 113191  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract HAADF-STEM tomography is a widely used experimental technique for analyzing nanometer-scale crystalline structures of a large variety of materials in three dimensions. Unfortunately, the acquisition of conventional HAADF-STEM tilt series can easily take up one hour or more, depending on the complexity of the experiment. It is therefore far from straightforward to investigate samples that do not withstand long acquisition or to acquire large amounts of tilt series during a single TEM experiment. The latter would lead to the ability to obtain statistically meaningful 3D data, or to perform in situ 3D characterizations with a much shorter time resolution. Various HAADF-STEM acquisition strategies have been proposed to accelerate the tomographic acquisition and reduce the required electron dose. These methods include tilting the holder continuously while acquiring a projection “movie” and a hybrid, incremental, methodology which combines the benefits of the conventional and continuous technique. However, until now an experimental evaluation has been lacking. In this paper, the different acquisition strategies will be experimentally compared in terms of speed, resolution and electron dose. This evaluation will be performed based on experimental tilt series acquired for various metallic nanoparticles with different shapes and sizes. We discuss the data processing involved with the fast HAADF-STEM tilt series and provide a general guideline when which acquisition strategy should be preferentially used.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000612539600003 Publication Date 2020-12-08  
  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 (up) 2.843 Times cited 15 Open Access OpenAccess  
  Notes We acknowledge Prof. Luis M. Liz-Marzán and co-workers of the Bionanoplasmonics Laboratory, CIC biomaGUNE, Spain for providing the Au@Ag nanoparticles, Prof. Sara. E. Skrabalak and co-workers of Indiana University, United States for the provision of the Au octopods and Prof. Teri W. Odom of Northwestern University, United States for the provision of the Au nanostars. H.V. acknowledges financial support by the Research Foundation Flanders (FWO grant 1S32617N). S.B acknowledges financial support by the Research Foundation Flanders (FWO grant G.0381.16N). This project received funding as well from the European Union’s Horizon 2020 research and innovation program under grant agreement No 731019 (EUSMI) and No 815128 (REALNANO). The authors acknowledge the entire EMAT technical staff for their support.; sygma Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @c:irua:174551 Serial 6660  
Permanent link to this record
 

 
Author Li, C.; Tardajos, A.P.; Wang, D.; Choukroun, D.; Van Daele, K.; Breugelmans, T.; Bals, S. url  doi
openurl 
  Title A simple method to clean ligand contamination on TEM grids Type A1 Journal article
  Year 2021 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 221 Issue Pages 113195  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)  
  Abstract 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” in the eld of electron mi- croscopy. This contamination is often more severe for scanning TEM, a technique that is based on a focused electron beam and hence higher electron dose rate. In this paper, we report a simple and effective method to clean drop-cast TEM grids that contain NPs with ligands. Using a combination of activated carbon and ethanol, this method effectively reduces the amount of ligands on TEM grids, and therefore greatly improves the quality of electron microscopy images and subsequent analytical measurements. This ef cient and facile method can be helpful during electron microscopy investigation of different kinds of nanomaterials that suffer from ligand- induced contamination.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000612539600002 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 (up) 2.843 Times cited 10 Open Access OpenAccess  
  Notes This research was funded by the University Antwerp GOA project (ID 33928). DW acknowledges an Individual Fellowship funded by the Marie Sklodowska-Curie Actions (MSCA) in Horizon 2020 program (grant 894254 SuprAtom). Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @c:irua:174947 Serial 6666  
Permanent link to this record
 

 
Author De wael, A.; De Backer, A.; Lobato, I.; Van Aert, S. pdf  url
doi  openurl
  Title Modelling ADF STEM images using elliptical Gaussian peaks and its effects on the quantification of structure parameters in the presence of sample tilt Type A1 Journal article
  Year 2021 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume Issue Pages 113391  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract A small sample tilt away from a main zone axis orientation results in an elongation of the atomic columns in ADF STEM images. An often posed research question is therefore whether the ADF STEM image intensities of tilted nanomaterials should be quantified using a parametric imaging model consisting of elliptical rather than the currently used symmetrical peaks. To this purpose, simulated ADF STEM images corresponding to different amounts of sample tilt are studied using a parametric imaging model that consists of superimposed 2D elliptical Gaussian peaks on the one hand and symmetrical Gaussian peaks on the other hand. We investigate the quantification of structural parameters such as atomic column positions and scattering cross sections using both parametric imaging models. In this manner, we quantitatively study what can be gained from this elliptical model for quantitative ADF STEM, despite the increased parameter space and computational effort. Although a qualitative improvement can be achieved, no significant quantitative improvement in the estimated structure parameters is achieved by the elliptical model as compared to the symmetrical model. The decrease in scattering cross sections with increasing sample tilt is even identical for both types of parametric imaging models. This impedes direct comparison with zone axis image simulations. Nonetheless, we demonstrate how reliable atom-counting can still be achieved in the presence of small sample tilt.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000704334200001 Publication Date 2021-09-24  
  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 (up) 2.843 Times cited Open Access OpenAccess  
  Notes This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887 and No. 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through grants to A.D.w. and A.D.B. and projects G.0502.18N, G.0267.18N, and EOS 30489208. S.V.A. acknowledges TOP BOF funding from the University of Antwerp.; esteem3JRA; esteem3reported Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @c:irua:181462 Serial 6810  
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Author Koo, J.; Dahl, A.B.; Bærentzen, J.A.; Chen, Q.; Bals, S.; Dahl, V.A. pdf  url
doi  openurl
  Title Shape from projections via differentiable forward projector for computed tomography Type A1 Journal article
  Year 2021 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 224 Issue Pages 113239  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract In computed tomography, the reconstruction is typically obtained on a voxel grid. In this work, however, we propose a mesh-based reconstruction method. For tomographic problems, 3D meshes have mostly been studied to simulate data acquisition, but not for reconstruction, for which a 3D mesh means the inverse process of estimating shapes from projections. In this paper, we propose a differentiable forward model for 3D meshes that bridge the gap between the forward model for 3D surfaces and optimization. We view the forward projection as a rendering process, and make it differentiable by extending recent work in differentiable rendering. We use the proposed forward model to reconstruct 3D shapes directly from projections. Experimental results for single-object problems show that the proposed method outperforms traditional voxel-based methods on noisy simulated data. We also apply the proposed method on electron tomography images of nanoparticles to demonstrate the applicability of the method on real data.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000744576800008 Publication Date 2021-03-11  
  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 (up) 2.843 Times cited 3 Open Access OpenAccess  
  Notes EU Horizon 2020 MSCA Innovative Training Network MUMMERING Grant Number 765604. Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @c:irua:183267 Serial 6825  
Permanent link to this record
 

 
Author Madsen, J.; Pennycook, T.J.; Susi, T. url  doi
openurl 
  Title ab initio description of bonding for transmission electron microscopy Type A1 Journal article
  Year 2021 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 231 Issue Pages  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The simulation of transmission electron microscopy (TEM) images or diffraction patterns is often required to interpret their contrast and extract specimen features. This is especially true for high-resolution phase-contrast imaging of materials, but electron scattering simulations based on atomistic models are widely used in materials science and structural biology. Since electron scattering is dominated by the nuclear cores, the scattering potential is typically described by the widely applied independent atom model. This approximation is fast and fairly accurate, especially for scanning TEM (STEM) annular dark-field contrast, but it completely neglects valence bonding and its effect on the transmitting electrons. However, an emerging trend in electron microscopy is to use new instrumentation and methods to extract the maximum amount of information from each electron. This is evident in the increasing popularity of techniques such as 4D-STEM combined with ptychography in materials science, and cryogenic microcrystal electron diffraction in structural biology, where subtle differences in the scattering potential may be both measurable and contain additional insights. Thus, there is increasing interest in electron scattering simulations based on electrostatic potentials obtained from first principles, mainly via density functional theory, which was previously mainly required for holography. In this Review, we discuss the motivation and basis for these developments, survey the pioneering work that has been published thus far, and give our outlook for the future. We argue that a physically better justified ab initio description of the scattering potential is both useful and viable for an increasing number of systems, and we expect such simulations to steadily gain in popularity and importance.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000744190300006 Publication Date 2021-03-18  
  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 (up) 2.843 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 2.843  
  Call Number UA @ admin @ c:irua:183955 Serial 6850  
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Author Wilmotte, A.; Turner, S.; van de Peer, Y.; Pace, N.R. doi  openurl
  Title Taxonomical study of marine oscillatorian strains (Cyanobacteria) with narrow trichomes: 2: nucleotide sequence analysis of the 16S ribosomal RNA Type A1 Journal article
  Year 1992 Publication Journal Of Phycology Abbreviated Journal J Phycol  
  Volume 28 Issue Pages 828-838  
  Keywords A1 Journal article; Electron Microscopy for Materials Science (EMAT);  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Baltimore, Md Editor  
  Language Wos A1992KH06800016 Publication Date 2004-10-26  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3646;1529-8817; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor (up) 2.844 Times cited 58 Open Access  
  Notes Approved no  
  Call Number UA @ lucian @ c:irua:11368 Serial 3470  
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Author Saraiva, M.; Chen, H.; Leroy, W.P.; Mahieu, S.; Jehanathan, N.; Lebedev, O.; Georgieva, V.; Persoons, R.; Depla, D. pdf  doi
openurl 
  Title Influence of Al content on the properties of MgO grown by reactive magnetron sputtering Type A1 Journal article
  Year 2009 Publication Plasma processes and polymers Abbreviated Journal Plasma Process Polym  
  Volume 6 Issue S:1 Pages S751-S754  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract In the present work, reactive magnetron sputtering in DC mode was used to grow complex oxide thin films, starting from two separate pure metal targets. A series of coatings was produced with a stoichiometry of the film ranging from MgO, over MgxAlyOz to Al2O3. The surface energy, crystallinity, hardness, refractive index, and surface roughness were investigated. A relationship between all properties studied and the Mg content of the samples was found. A critical compositional region for the Mg-Al-O system where all properties exhibit a change was noticed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Weinheim Editor  
  Language Wos 000272302900144 Publication Date 2009-09-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1612-8850; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor (up) 2.846 Times cited 13 Open Access  
  Notes Iwt Approved Most recent IF: 2.846; 2009 IF: 4.037  
  Call Number UA @ lucian @ c:irua:79363 Serial 1613  
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Author Garzia Trulli, M.; Claes, N.; Pype, J.; Bals, S.; Baert, K.; Terryn, H.; Sardella, E.; Favia, P.; Vanhulsel, A. pdf  url
doi  openurl
  Title Deposition of aminosilane coatings on porous Al2O3microspheres by means of dielectric barrier discharges Type A1 Journal article
  Year 2017 Publication Plasma processes and polymers Abbreviated Journal Plasma Process Polym  
  Volume 14 Issue 14 Pages 1600211  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)  
  Abstract Advances in the synthesis of porous microspheres and in their functionalization are increasing the interest in applications of alumina. This paper deals with coatings plasma deposited from 3-aminopropyltriethoxysilane by means of dielectric barrier discharges on alumina porous microspheres, shaped by a vibrational droplet coagulation technique. Aims of the work are the functionalization of the particles with active amino groups, as well as the evaluation of their surface coverage and of the penetration of the coatings into their pores. A multi-diagnostic approach was used for the chemical/morphological characterization of the particles. It was found that 5 min exposure to plasma discharges promotes the deposition of homogeneous coatings onto the microspheres and within their pores, down to 1 μm.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000410773200003 Publication Date 2017-01-05  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1612-8850 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor (up) 2.846 Times cited 8 Open Access OpenAccess  
  Notes The technical assistance of the VITO staff (Materials Dpt.) is gratefully acknowledged, especially D. Havermans, E. Van Hoof, R. Kemps (SEM-EDX), and A. De Wilde (Hg Porosimetry). Drs. S. Mullens and G. Scheltjens are kindly acknowledged for constructive discussions. Strategic Initiative Materials in Flanders (SIM) is gratefully acknowledged for its financial support. This research was carried out in the framework of the SIM-TRAP program (Tools for rational processing of nano-particles: controlling and tailoring nanoparticle based or nanomodified particle based materials). N. Claes and S. Bals acknowledge financial support from European Research Council (ERC Starting Grant #335078-COLOURATOM). (ROMEO:white; preprint:; postprint:restricted ; pdfversion:cannot); saraecas; ECAS_Sara; Approved Most recent IF: 2.846  
  Call Number EMAT @ emat @ c:irua:139511UA @ admin @ c:irua:139511 Serial 4342  
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Author Molina, L.; Tan, H.; Biermans, E.; Batenburg, K.J.; Verbeeck, J.; Bals, S.; Van Tendeloo, G. pdf  doi
openurl 
  Title Barrier efficiency of sponge-like La2Zr2O7 buffer layers for YBCO-coated conductors Type A1 Journal article
  Year 2011 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech  
  Volume 24 Issue 6 Pages 065019-065019,8  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract Solution derived La2Zr2O7 films have drawn much attention for potential applications as thermal barriers or low-cost buffer layers for coated conductor technology. Annealing and coating parameters strongly affect the microstructure of La2Zr2O7, but different film processing methods can yield similar microstructural features such as nanovoids and nanometer-sized La2Zr2O7 grains. Nanoporosity is a typical feature found in such films and the implications for the functionality of the films are investigated by a combination of scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS) and quantitative electron tomography. Chemical solution based La2Zr2O7 films deposited on flexible Ni5 at.%W substrates with a {100}lang001rang biaxial texture were prepared for an in-depth characterization. A sponge-like structure composed of nanometer-sized voids is revealed by high-angle annular dark-field scanning transmission electron microscopy in combination with electron tomography. A three-dimensional quantification of nanovoids in the La2Zr2O7 film is obtained on a local scale. Mostly non-interconnected highly faceted nanovoids compromise more than one-fifth of the investigated sample volume. The diffusion barrier efficiency of a 170 nm thick La2Zr2O7 film is investigated by STEM-EELS, yielding a 1.8 ± 0.2 nm oxide layer beyond which no significant nickel diffusion can be detected and intermixing is observed. This is of particular significance for the functionality of YBa2Cu3O7 − δ coated conductor architectures based on solution derived La2Zr2O7 films as diffusion barriers.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Bristol Editor  
  Language Wos 000290472900021 Publication Date 2011-04-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor (up) 2.878 Times cited 31 Open Access  
  Notes Esteem 026019; Fwo Approved Most recent IF: 2.878; 2011 IF: 2.662  
  Call Number UA @ lucian @ c:irua:88639UA @ admin @ c:irua:88639 Serial 221  
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