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	Author	Zhang, X.B.; Zhang, X.F.; Amelinckx, S.; Van Tendeloo, G.; van Landuyt, J.
	Title	The reciprocal space of carbon tubes: a detailed interpretation of the electron diffraction effects			Type	A1 Journal article
	Year	1994	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	54	Issue		Pages	237-249
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	A1994PA59800016	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; WoS citing articles
	Impact Factor	2.436	Times cited	59	Open Access
	Notes				Approved
	Call Number	UA @ lucian @ c:irua:10006			Serial	2844
Permanent link to this record



	Author	Amelinckx, S.; Milat, O.; Van Tendeloo, G.
	Title	Selective imaging of sublattices in complex structures			Type	A1 Journal article
	Year	1993	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	51	Issue		Pages	90-108
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	A1993LN79100010	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; WoS citing articles
	Impact Factor	2.436	Times cited	8	Open Access
	Notes				Approved	CHEMISTRY, PHYSICAL 54/144 Q2 # PHYSICS, ATOMIC, MOLECULAR & CHEMICAL 9/35 Q2 #
	Call Number	UA @ lucian @ c:irua:6835			Serial	2964
Permanent link to this record



	Author	Zhang, X.F.; Zhang, X.B.; Bernaerts, D.; Van Tendeloo, G.; Amelinckx, S.; van Landuyt, J.; Werner, H.
	Title	A simple preparation method for air-sensitive specimens for transmission electron microscopy demonstrated by Rb₆C₆₀			Type	A1 Journal article
	Year	1994	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	55	Issue		Pages	25-30
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	In this paper a particularly simple but efficient method is presented by which samples of alkali-doped C-60 materials or other air-sensitive materials can be prepared and transferred into a transmission electron microscope for direct observations and investigations. Flexible, transparent glove bags are used which are filled to a slight overpressure with dry nitrogen. Under this protective atmosphere, the air-sensitive sample is mounted in the specimen holder and inserted in the vacuum of the electron microscope. Rb6C60 which is prepared and transferred into the microscope in this way has been investigated by transmission electron microscopy (TEM). The results confirm the bcc structure and especially the location of the rubidium atoms.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	A1994PE30800005	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; WoS citing articles
	Impact Factor	2.436	Times cited	2	Open Access
	Notes				Approved	CHEMISTRY, PHYSICAL 77/144 Q3 # MATHEMATICS, INTERDISCIPLINARY 19/101 Q1 # PHYSICS, ATOMIC, MOLECULAR & CHEMICAL 17/35 Q2 #
	Call Number	UA @ lucian @ c:irua:10007			Serial	3002
Permanent link to this record



	Author	Milat, O.; Van Tendeloo, G.; Amelinckx, S.
	Title	Selective imaging of the “substructures” in incommensurately modulated intergrowth crystal structures			Type	A1 Journal article
	Year	1992	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	41	Issue		Pages	65-76
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	A1992HX68100006	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; WoS citing articles
	Impact Factor	2.436	Times cited	5	Open Access
	Notes				Approved	MATERIALS SCIENCE, MULTIDISCIPLINARY 96/271 Q2 #
	Call Number	UA @ lucian @ c:irua:4437			Serial	2966
Permanent link to this record



	Author	Velazco, A.; Béché, A.; Jannis, D.; Verbeeck, J.
	Title	Reducing electron beam damage through alternative STEM scanning strategies, Part I: Experimental findings			Type	A1 Journal article
	Year	2022	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	232	Issue		Pages	113398
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The highly energetic electrons in a transmission electron microscope (TEM) can alter or even completely destroy the structure of samples before sufficient information can be obtained. This is especially problematic in the case of zeolites, organic and biological materials. As this effect depends on both the electron beam and the sample and can involve multiple damage pathways, its study remained difficult and is plagued with irreproducibility issues, circumstantial evidence, rumors, and a general lack of solid data. Here we take on the experimental challenge to investigate the role of the STEM scan pattern on the damage behavior of a commercially available zeolite sample with the clear aim to make our observations as reproducible as possible. We make use of a freely programmable scan engine that gives full control over the tempospatial distribution of the electron probe on the sample and we use its flexibility to obtain multiple repeated experiments under identical conditions comparing the difference in beam damage between a conventional raster scan pattern and a newly proposed interleaved scan pattern that provides exactly the same dose and dose rate and visits exactly the same scan points. We observe a significant difference in beam damage for both patterns with up to 11 % reduction in damage (measured from mass loss). These observations demonstrate without doubt that electron dose, dose rate and acceleration voltage are not the only parameters affecting beam damage in (S)TEM experiments and invite the community to rethink beam damage as an unavoidable consequence of applied electron dose.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000714819200002	Publication Date	2021-10-02
	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	18	Open Access	OpenAccess
	Notes	A.V., D.J., 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.; JRA; reported			Approved	Most recent IF: 2.2
	Call Number	EMAT @ emat @c:irua:183282			Serial	6818
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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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	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
Permanent link to this record



	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 (
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000734396800009	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		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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	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	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	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	Velazco, A.; Nord, M.; Béché, A.; Verbeeck, J.
	Title	Evaluation of different rectangular scan strategies for STEM imaging			Type	A1 Journal article
	Year	2020	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume		Issue		Pages	113021
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	STEM imaging is typically performed by raster scanning a focused electron probe over a sample. Here we investigate and compare three different scan patterns, making use of a programmable scan engine that allows to arbitrarily set the sequence of probe positions that are consecutively visited on the sample. We compare the typical raster scan with a so-called ‘snake’ pattern where the scan direction is reversed after each row and a novel Hilbert scan pattern that changes scan direction rapidly and provides an homogeneous treatment of both scan directions. We experimentally evaluate the imaging performance on a single crystal test sample by varying dwell time and evaluating behaviour with respect to sample drift. We demonstrate the ability of the Hilbert scan pattern to more faithfully represent the high frequency content of the image in the presence of sample drift. It is also shown that Hilbert scanning provides reduced bias when measuring lattice parameters from the obtained scanned images while maintaining similar precision in both scan directions which is especially important when e.g. performing strain analysis. Compared to raster scanning with flyback correction, both snake and Hilbert scanning benefit from dose reduction as only small probe movement steps occur.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000544042800007	Publication Date	2020-05-21
	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	2.2	Times cited	13	Open Access	OpenAccess
	Notes	A.V., A.B. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. M.N. received support for this work from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 838001. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3.			Approved	Most recent IF: 2.2; 2020 IF: 2.843
	Call Number	EMAT @ emat @c:irua:169225			Serial	6369
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	Author	Fatermans, J.; den Dekker, Aj.; Müller-Caspary, K.; Gauquelin, N.; Verbeeck, J.; Van Aert, S.
	Title	Atom column detection from simultaneously acquired ABF and ADF STEM images			Type	A1 Journal article
	Year	2020	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	219	Issue		Pages	113046
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	In electron microscopy, the maximum a posteriori (MAP) probability rule has been introduced as a tool to determine the most probable atomic structure from high-resolution annular dark-field (ADF) scanning transmission electron microscopy (STEM) images exhibiting low contrast-to-noise ratio (CNR). Besides ADF imaging, STEM can also be applied in the annular bright-field (ABF) regime. The ABF STEM mode allows to directly visualize light-element atomic columns in the presence of heavy columns. Typically, light-element nanomaterials are sensitive to the electron beam, limiting the incoming electron dose in order to avoid beam damage and leading to images exhibiting low CNR. Therefore, it is of interest to apply the MAP probability rule not only to ADF STEM images, but to ABF STEM images as well. In this work, the methodology of the MAP rule, which combines statistical parameter estimation theory and model-order selection, is extended to be applied to simultaneously acquired ABF and ADF STEM images. For this, an extension of the commonly used parametric models in STEM is proposed. Hereby, the effect of specimen tilt has been taken into account, since small tilts from the crystal zone axis affect, especially, ABF STEM intensities. Using simulations as well as experimental data, it is shown that the proposed methodology can be successfully used to detect light elements in the presence of heavy elements.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000594768500005	Publication Date	2020-06-01
	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	2.2	Times cited	9	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, EOS 30489208). 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 funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 823717 – ESTEEM3. The direct electron detector (Medipix3, Quantum Detectors) was funded by the Hercules fund from the Flemish Government. K. M. C. acknowledges funding from the Initiative and Network Fund of the Helmholtz Association (Germany) under contract VH-NG-1317. The authors thank Mark Huijben from the University of Twente (Enschede, The Netherlands) for providing the LiMn2O4 sample used in section 4.2 of this study. N. G., J. V., and S. V. A. acknowledge funding from the University of Antwerp through the Concerted Research Actions (GOA) project Solarpaint and the TOP project.			Approved	Most recent IF: 2.2; 2020 IF: 2.843
	Call Number	EMAT @ emat @c:irua:169706			Serial	6373
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	Author	Prabhakara, V.; Jannis, D.; Guzzinati, G.; Béché, A.; Bender, H.; Verbeeck, J.
	Title	HAADF-STEM block-scanning strategy for local measurement of strain at the nanoscale			Type	A1 Journal article
	Year	2020	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	219	Issue		Pages	113099
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Lattice strain measurement of nanoscale semiconductor devices is crucial for the semiconductor industry as strain substantially improves the electrical performance of transistors. High resolution scanning transmission electron microscopy (HR-STEM) imaging is an excellent tool that provides spatial resolution at the atomic scale and strain information by applying Geometric Phase Analysis or image fitting procedures. However, HR-STEM images regularly suffer from scanning distortions and sample drift during image acquisition. In this paper, we propose a new scanning strategy that drastically reduces artefacts due to drift and scanning distortion, along with extending the field of view. It consists of the acquisition of a series of independent small subimages containing an atomic resolution image of the local lattice. All subimages are then analysed individually for strain by fitting a nonlinear model to the lattice images. The method allows flexible tuning of spatial resolution and the field of view within the limits of the dynamic range of the scan engine while maintaining atomic resolution sampling within the subimages. The obtained experimental strain maps are quantitatively benchmarked against the Bessel diffraction technique. We demonstrate that the proposed scanning strategy approaches the performance of the diffraction technique while having the advantage that it does not require specialized diffraction cameras.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000594768500006	Publication Date	2020-09-01
	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	2.2	Times cited	4	Open Access	OpenAccess
	Notes	A.B. D.J. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. The Qu-Ant-EM microscope and the direct electron detector used in the diffraction experiments was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the GOA project “Solarpaint” of the University of Antwerp. GG acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek – Vlaanderen (FWO). Special thanks to Dr. Thomas Nuytten, Prof. Dr. Wilfried Vandervorst, Dr. Paola Favia, Dr. Olivier Richard from IMEC, Leuven and Prof. Dr. Sara Bals from EMAT, Antwerp for their continuous support and collaboration with the project and to the IMEC processing group for the device fabrication.			Approved	Most recent IF: 2.2; 2020 IF: 2.843
	Call Number	EMAT @ emat @c:irua:172485			Serial	6404
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	Author	De wael, A.; De Backer, A.; Van Aert, S.
	Title	Hidden Markov model for atom-counting from sequential ADF STEM images: Methodology, possibilities and limitations			Type	A1 Journal article
	Year	2020	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	219	Issue		Pages	113131
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We present a quantitative method which allows us to reliably measure dynamic changes in the atomic structure of monatomic crystalline nanomaterials from a time series of atomic resolution annular dark field scanning transmission electron microscopy images. The approach is based on the so-called hidden Markov model and estimates the number of atoms in each atomic column of the nanomaterial in each frame of the time series. We discuss the origin of the improved performance for time series atom-counting as compared to the current state-of-the-art atom-counting procedures, and show that the so-called transition probabilities that describe the probability for an atomic column to lose or gain one or more atoms from frame to frame are particularly important. Using these transition probabilities, we show that the method can also be used to estimate the probability and cross section related to structural changes. Furthermore, we explore the possibilities for applying the method to time series recorded under variable environmental conditions. The method is shown to be promising for a reliable quantitative analysis of dynamic processes such as surface diffusion, adatom dynamics, beam effects, or in situ experiments.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000594770500003	Publication Date	2020-10-03
	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	2.2	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 and EOS 30489208.			Approved	Most recent IF: 2.2; 2020 IF: 2.843
	Call Number	EMAT @ emat @c:irua:172449			Serial	6417
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	Author	Gorji, S.; Kashiwar, A.; Mantha, L.S.; Kruk, R.; Witte, R.; Marek, P.; Hahn, H.; Kübel, C.; Scherer, T.
	Title	Nanowire facilitated transfer of sensitive TEM samples in a FIB			Type	A1 Journal article
	Year	2020	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	219	Issue		Pages	113075
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	We introduce a facile approach to transfer thin films and other mechanically sensitive TEM samples inside a FIB with minimal introduction of stress and bending. The method is making use of a pre-synthetized flexible freestanding Ag nanowire attached to the tip of a typical tungsten micromanipulator inside the FIB. The main advantages of this approach are the significantly reduced stress-induced bending during transfer and attachment of the TEM sample, the very short time required to attach and cut the nanowire, the operation at very low dose and ion current, and only using the e-beam for Pt deposition during the transfer of sensitive TEM samples. This results in a reduced sample preparation time and reduced exposure to the ion beam or e-beam for Pt deposition during the sample preparation and thus also reduced contamination and beam damage. The method was applied to a number of thin films and different TEM samples in order to illustrate the advantageous benefits of the concept. In particular, the technique has been successfully tested for the transfer of a thin film onto a MEMS heating chip for in situ TEM experiments.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2020-07-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991	ISBN		Additional Links	UA library record
	Impact Factor	2.2	Times cited		Open Access
	Notes				Approved	Most recent IF: 2.2; 2020 IF: 2.843
	Call Number	UA @ admin @ c:irua:183618			Serial	6871
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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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	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	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000953765800001	Publication Date	2023-02-10
	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	2.2	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.
	Address
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001011617200001	Publication Date	2023-06-01
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991	ISBN		Additional Links	UA library record; WoS full record
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001026912700001	Publication Date	2023-06-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991	ISBN		Additional Links	UA library record; WoS full record
	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	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2023-08-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	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	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)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001164447000001	Publication Date	2024-01-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991	ISBN		Additional Links	UA library record; WoS full record
	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	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001089064200001	Publication Date	2023-09-23
	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	2.2	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	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2024-02-19
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	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	Gao, C.; Hofer, C.; Pennycook, T.J.
	Title	On central focusing for contrast optimization in direct electron ptychography of thick samples			Type	A1 Journal article
	Year	2024	Publication	Ultramicroscopy	Abbreviated Journal
	Volume	256	Issue		Pages	113879-7
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the projected potential becomes strong for both direct and iterative inversion ptychography methods. It has recently been shown that these reversals can often be counteracted in direct ptychography methods by adapting the focus. Here we provide an explanation of why the best contrast is often found with the probe focused to the middle of the sample. The phase contribution due to defocus at each sample slice above and below the central plane in this configuration effectively cancels out, which can prevent contrast reversals when dynamical scattering effects are not overly strong. In addition we show that the convergence angle can be an important consideration for removal of contrast reversals in relatively thin samples.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001112166400001	Publication Date	2023-11-03
	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	2.2	Times cited		Open Access	Not_Open_Access
	Notes				Approved	Most recent IF: 2.2; 2024 IF: 2.843
	Call Number	UA @ admin @ c:irua:202029			Serial	9066
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	Author	Zanaga, D.; Altantzis, T.; Sanctorum, J.; Freitag, B.; Bals, S.
	Title	An alternative approach for ζ-factor measurement using pure element nanoparticles			Type	A1 Journal article
	Year	2016	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	164	Issue	164	Pages	11-16
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	It is very challenging to measure the chemical composition of hetero nanostructures in a reliable and quantitative manner. Here, we propose a novel and straightforward approach that can be used to quantify energy dispersive X-ray spectra acquired in a transmission electron microscope. Our method is based on a combination of electron tomography and the so-called ζ-factor technique. We will demonstrate the reliability of our approach as well as its applicability by investigating Au-Ag and Au-Pt hetero nanostructures. Given its simplicity, we expect that the method could become a new standard in the field of chemical characterization using electron microscopy.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000373526200002	Publication Date	2016-03-10
	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	19	Open Access	OpenAccess
	Notes	The authors acknowledge financial support from the European Research Council (ERC Starting Grant # 335078-COLOURATOMS) and the European Union under the FP7 (Integrated Infrastructure Initiative N. 312483 – ESTEEM2). The authors would also like to thank Luis M. Liz-Marzán, Ana Sánchez-Iglesias, Stefanos Mourdikoudis and Cristina Fernández-López for sample provision and useful discussions.; esteem2jra4; ECASSara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot);			Approved	Most recent IF: 2.843
	Call Number	EMAT @ emat @			Serial	4019
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	Author	Lobato, I.; Van Aert, S.; Verbeeck, J.
	Title	Progress and new advances in simulating electron microscopy datasets using MULTEM			Type	A1 Journal article
	Year	2016	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	168	Issue	168	Pages	17-27
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	A new version of the open source program MULTEM is presented here. It includes a graphical user interface, tapering truncation of the atomic potential, CPU multithreading functionality, single/double precision calculations, scanning transmission electron microscopy (STEM) simulations using experimental detector sensitivities, imaging STEM (ISTEM) simulations, energy filtered transmission electron microscopy (EFTEM) simulations, STEM electron energy loss spectroscopy (EELS) simulations along with other improvements in the algorithms. We also present a mixed channeling approach for the calculation of inelastic excitations, which allows one to considerably speed up time consuming EFTEM/STEM-EELS calculations.
	Address	EMAT, University of Antwerp, Department of Physics, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Wos	000380754100003	Publication Date	2016-06-11
	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	43	Open Access
	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 and G.0368.15N).; esteem2jra3; esteem2na3; esteem2_jra2			Approved	Most recent IF: 2.843
	Call Number	c:irua:134088 c:irua:134088UA @ admin @ c:irua:134088			Serial	4093
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	Author	Béché, A.; Juchtmans, R.; Verbeeck, J.
	Title	Efficient creation of electron vortex beams for high resolution STEM imaging			Type	A1 Journal article
	Year	2017	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	178	Issue	178	Pages	12-19
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The recent discovery of electron vortex beams carrying quantised angular momentum in the TEM has led to an active field of research, exploring a variety of potential applications including the possibility of mapping magnetic states at the atomic scale. A prerequisite for this is the availability of atomic sized electron vortex beams at high beam current and mode purity. In this paper we present recent progress showing that by making use of the Aharonov-Bohm effect near the tip of a long single domain ferromagnetic Nickel needle, a very efficient aperture for the production of electron vortex beams can be realised. The aperture transmits more than 99% of all electrons and provides a vortex mode purity of up to 92%. Placing this aperture in the condenser plane of a state of the art Cs corrected microscope allows us to demonstrate atomic resolution HAADF STEM images with spatial resolution better than 1 Angstrom, in agreement with theoretical expectations and only slightly inferior to the performance of a non-vortex probe on the same instrument.
	Address	EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Wos	000403862900003	Publication Date	2016-05-10
	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	30	Open Access	OpenAccess
	Notes	A.B. and J.V. acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant No. 278510 VORTEX. J.V. acknowledges funding from FWO project G.0044.13N ('Charge ordering').; ECASJO_;			Approved	Most recent IF: 2.843
	Call Number	c:irua:134085 c:irua:134085UA @ admin @ c:irua:134085			Serial	4094
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	Author	Muller-Caspary, K.; Krause, F.F.; Grieb, T.; Loffler, S.; Schowalter, M.; Béché, A.; Galioit, V.; Marquardt, D.; Zweck, J.; Schattschneider, P.; Verbeeck, J.; Rosenauer, A.
	Title	Measurement of atomic electric fields and charge densities from average momentum transfers using scanning transmission electron microscopy			Type	A1 Journal article
	Year	2016	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	178	Issue	178	Pages	62-80
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	This study sheds light on the prerequisites, possibilities, limitations and interpretation of high-resolution differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). We draw particular attention to the well-established DPC technique based on segmented annular detectors and its relation to recent developments based on pixelated detectors. These employ the expectation value of the momentum transfer as a reliable measure of the angular deflection of the STEM beam induced by an electric field in the specimen. The influence of scattering and propagation of electrons within the specimen is initially discussed separately and then treated in terms of a two-state channeling theory. A detailed simulation study of GaN is presented as a function of specimen thickness and bonding. It is found that bonding effects are rather detectable implicitly, e.g., by characteristics of the momentum flux in areas between the atoms than by directly mapping electric fields and charge densities. For strontium titanate, experimental charge densities are compared with simulations and discussed with respect to experimental artifacts such as scan noise. Finally, we consider practical issues such as figures of merit for spatial and momentum resolution, minimum electron dose, and the mapping of larger-scale, built-in electric fields by virtue of data averaged over a crystal unit cell. We find that the latter is possible for crystals with an inversion center. Concerning the optimal detector design, this study indicates that a sampling of 5mrad per pixel is sufficient in typical applications, corresponding to approximately 10x10 available pixels.
	Address	Institut fur Festkr perphysik, Universitat Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Wos	000403862900009	Publication Date	2016-05-12
	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	2.843	Times cited	93	Open Access
	Notes	K.M.-C. acknowledges support from the Deutsche Forschungsgemeinschaft (DFG) under contract MU3660/1-1. This work was further supported by the DFG under contract RO2057/4-2 and O2057/11-1. J.V. and A.B. acknowledge funding from the European Research Council (ERC) under the 7th Framework Program (FP7), and ERC Starting Grant No. 278510-VORTEX. Experimental results are obtained on the Qu-Ant-EM microscope partly funded by the Hercules fund from the Flemish government. J.V. also acknowledges funding through a GOA project “Solarpaint” of the University of Antwerp. SL and PS acknowledge financial support by the Austrian Science Fund (FWF) under grants No. I543-N20 and J3732-N27. ECASJO_;			Approved	Most recent IF: 2.843
	Call Number	c:irua:134125UA @ admin @ c:irua:134125			Serial	4098
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	Author	Goris, B.; Meledina, M.; Turner, S.; Zhong, Z.; Batenburg, K.J.; Bals, S.
	Title	Three dimensional mapping of Fe dopants in ceria nanocrystals using direct spectroscopic electron tomography			Type	A1 Journal article
	Year	2016	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	171	Issue	171	Pages	55-62
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Electron tomography is a powerful technique for the 3D characterization of the morphology of nanostructures. Nevertheless, resolving the chemical composition of complex nanostructures in 3D remains challenging and the number of studies in which electron energy loss spectroscopy (EELS) is combined with tomography is limited. During the last decade, dedicated reconstruction algorithms have been developed for HAADF-STEM tomography using prior knowledge about the investigated sample. Here, we will use the prior knowledge that the experimental spectrum of each reconstructed voxel is a linear combination of a well-known set of references spectra in a so-called direct spectroscopic tomography technique. Based on a simulation experiment, it is shown that this technique provides superior results in comparison to conventional reconstruction methods for spectroscopic data, especially for spectrum images containing a relatively low signal to noise ratio. Next, this technique is used to investigate the spatial distribution of Fe dopants in Fe:Ceria nanoparticles in 3D. It is shown that the presence of the Fe2+ dopants is correlated with a reduction of the Ce atoms from Ce4+ towards Ce3+. In addition, it is demonstrated that most of the Fe dopants are located near the voids inside the nanoparticle.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000389106200007	Publication Date	2016-09-06
	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	2.843	Times cited	13	Open Access	OpenAccess
	Notes	The work was supported by the Research Foundation Flanders (FWO Vlaanderen) by project funding (G038116N, 3G004613) and by a post-doctoral research grants to B.G. S.B. acknowledges funding from the European Research Council (Starting Grant no. COLOURATOMS 335078). K.J.B. acknowledges funding from The Netherlands Organization for Scientific Research (NWO) (program 639.072.005.). We would like to thank Dr. Hilde Poelman, Dr. Vladimir Galvita and Prof. Dr. Guy B. Marin for the synthesis of the investigated sample.; ECAS_Sara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot);			Approved	Most recent IF: 2.843
	Call Number	c:irua:135185 c:irua:135185			Serial	4123
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	Author	Kirilenko, D.A.; Brunkov, P.N.
	Title	Measuring the height-to-height correlation function of corrugation in suspended graphene			Type	A1 Journal article
	Year	2016	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	165	Issue	165	Pages	1-7
	Keywords	A1 Journal article; Electron Microscopy for Materials Science (EMAT);
	Abstract	Nanocorrugation of 2D crystals is an important phenomenon since it affects their electronic and mechanical properties. The corrugation may have various sources; one of them is flexural phonons that, in particular, are responsible for the thermal conductivity of graphene. A study of corrugation of just the suspended graphene can reveal much of valuable information on the physics of this complicated phenomenon. At the same time, the suspended crystal nanorelief can hardly be measured directly because of high flexibility of the 2D crystal. Moreover, the relief portion related to rapid out-of-plane oscillations (flexural phonons) is also inaccessible by such measurements. Here we present a technique for measuring the Fourier components of the height-height correlation function H(q) of suspended graphene which includes the effect of flexural phonons. The technique is based on the analysis of electron diffraction patterns. The H(q) is measured in the range of wavevectors q approximately 0.4-4.5nm(-1). At the upper limit of this range H(q) does follow the T/kappaq(4) law. So, we measured the value of suspended graphene bending rigidity kappa=1.2+/-0.4eV at ambient temperature T approximately 300K. At intermediate wave vectors, H(q) follows a slightly weaker exponent than theoretically predicted q(-3.15) but is closer to the results of the molecular dynamics simulation. At low wave vectors, the dependence becomes even weaker, which may be a sign of influence of charge carriers on the dynamics of undulations longer than 10nm. The technique presented can be used for studying physics of flexural phonons in other 2D materials.
	Address	Ioffe Institute, Politekhnicheskaya ul. 26, 194021 St-Petersburg, Russia; ITMO University, Kronverksky pr. 49, 197101 St. Petersburg, Russia
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Wos	000375946200001	Publication Date	2016-03-28
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991	ISBN		Additional Links
	Impact Factor	2.843	Times cited	3	Open Access
	Notes	D.K. thanks the RFBR (Grant no. 16-32-60165) for the partial support of this research. The work was carried out in part at the Joint Research Center “Material Science and Characterization in Advanced Technologies” (St-Petersburg, Russia) under the financial support from the Ministry of Education and Science of the Russian Federation (Agreement 14.621.21.0007, 04.12.2014, id RFMEFI62114X0007, the use of the Jeol JEM-2100F microscope) and at EMAT, Universiteit Antwerpen (Antwerpen, Belgium), (the use of the FEI Tecnai G2 microscope).			Approved	Most recent IF: 2.843
	Call Number	EMAT @ emat @			Serial	4124
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