NANOlab Center of Excellence literature database -- Query Results

	NANOlab Center of Excellence literature database Home \| Show All \| Simple Search \| Advanced Search	Login Quick Search: Field: contains: ...
	1–30 of 61 records found matching your query (RSS \| history):

Select All Deselect All

<< 1 2 3 >>

List View

Citations

Details

	Records
	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
Permanent link to this record



	Author	Van Aert, S.; De Backer, A.; Martinez, G.T.; den Dekker, A.J.; Van Dyck, D.; Bals, S.; Van Tendeloo, G.
	Title	Advanced electron crystallography through model-based imaging			Type	A1 Journal article
	Year	2016	Publication	IUCrJ	Abbreviated Journal	Iucrj
	Volume	3	Issue	3	Pages	71-83
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab; Engineering Management (ENM)
	Abstract	The increasing need for precise determination of the atomic arrangement of non-periodic structures in materials design and the control of nanostructures explains the growing interest in quantitative transmission electron microscopy. The aim is to extract precise and accurate numbers for unknown structure parameters including atomic positions, chemical concentrations and atomic numbers. For this purpose, statistical parameter estimation theory has been shown to provide reliable results. In this theory, observations are considered purely as data planes, from which structure parameters have to be determined using a parametric model describing the images. As such, the positions of atom columns can be measured with a precision of the order of a few picometres, even though the resolution of the electron microscope is still one or two orders of magnitude larger. Moreover, small differences in average atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark-field scanning transmission electron microscopy images. In addition, this theory allows one to measure compositional changes at interfaces, to count atoms with single-atom sensitivity, and to reconstruct atomic structures in three dimensions. This feature article brings the reader up to date, summarizing the underlying theory and highlighting some of the recent applications of quantitative model-based transmisson electron microscopy.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000368590900010	Publication Date	2015-11-13
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2052-2525;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	5.793	Times cited	30	Open Access	OpenAccess
	Notes	The authors gratefully acknowledge the Research Foundation Flanders (FWO, Belgium) for funding and for a PhD grant to ADB. The research leading to these results has received funding from the European Union 7th Framework Program (FP7/20072013) under grant agreement No. 312483 (ESTEEM2). SB and GVT acknowledge the European Research Council under the 7th Framework Program (FP7), ERC grant No. 335078 – COLOURATOMS and ERC grant No. 246791 – COUNTATOMS.; esteem2jra2; ECASSara; (ROMEO:green; preprint:; postprint:can ; pdfversion:can);			Approved	Most recent IF: 5.793
	Call Number	c:irua:129589 c:irua:129589			Serial	3965
Permanent link to this record



	Author	Fatermans, J.; de Backer, A.; den Dekker, A.J.; Van Aert, S.
	Title	Atom column detection			Type	H2 Book chapter
	Year	2021	Publication	Advances in imaging and electron physics T2 – Advances in imaging and electron physics	Abbreviated Journal
	Volume		Issue		Pages	177-214
	Keywords	H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	By combining statistical parameter estimation and model-order selection using a Bayesian framework, the maximum a posteriori (MAP) probability rule is proposed in this chapter as an objective and quantitative method to detect atom columns from high-resolution scanning transmission electron microscopy (HRSTEM) images. The validity and usefulness of this approach is demonstrated to both simulated and experimental annular dark-field (ADF) STEM images, but also to simultaneously acquired annular bright-field (ABF) and ADF STEM image data.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2021-03-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume	217	Series Issue		Edition
	ISSN		ISBN	978-0-12-824607-8; 1076-5670	Additional Links	UA library record
	Impact Factor		Times cited		Open Access	Not_Open_Access
	Notes	ERC Consolidator project funded by the European Union grant #770887 Picometrics			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:177531			Serial	6775
Permanent link to this record



	Author	de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S.
	Title	Atom counting			Type	H2 Book chapter
	Year	2021	Publication	Advances in imaging and electron physics T2 – Advances in imaging and electron physics	Abbreviated Journal
	Volume		Issue		Pages	91-144
	Keywords	H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	In this chapter, a statistical model-based method to count the number of atoms of monotype crystalline nanostructures from high-resolution annular dark-field (ADF) scanning transmission electron microscopy (STEM) images is discussed in detail together with a thorough study on the possibilities and inherent limitations. We show that this method can be applied to nanocrystals of arbitrary shape, size, and atom type. The validity of the atom-counting results is confirmed by means of detailed image simulations and it is shown that the high sensitivity of our method enables us to count atoms with single atom sensitivity.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2021-03-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume	217	Series Issue		Edition
	ISSN		ISBN	978-0-12-824607-8; 1076-5670	Additional Links	UA library record
	Impact Factor		Times cited		Open Access	Not_Open_Access
	Notes	ERC Consolidator project funded by the European Union grant #770887 Picometrics			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:177529			Serial	6776
Permanent link to this record



	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; Atomic resolution scanning transmission electron microscopy; Atom counting; Heterogeneous nanostructures; Multivariate Gaussian mixture model; 4D STEM; Electron Microscopy for Materials Science (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
	Impact Factor	2.2	Times cited		Open Access	Not_Open_Access
	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
Permanent link to this record



	Author	de Backer, A.; Martinez, G.T.; Rosenauer, A.; Van Aert, S.
	Title	Atom counting in HAADF STEM using a statistical model-based approach : methodology, possibilities, and inherent limitations			Type	A1 Journal article
	Year	2013	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	134	Issue		Pages	23-33
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	In the present paper, a statistical model-based method to count the number of atoms of monotype crystalline nanostructures from high resolution high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) images is discussed in detail together with a thorough study on the possibilities and inherent limitations. In order to count the number of atoms, it is assumed that the total scattered intensity scales with the number of atoms per atom column. These intensities are quantitatively determined using model-based statistical parameter estimation theory. The distribution describing the probability that intensity values are generated by atomic columns containing a specific number of atoms is inferred on the basis of the experimental scattered intensities. Finally, the number of atoms per atom column is quantified using this estimated probability distribution. The number of atom columns available in the observed STEM image, the number of components in the estimated probability distribution, the width of the components of the probability distribution, and the typical shape of a criterion to assess the number of components in the probability distribution directly affect the accuracy and precision with which the number of atoms in a particular atom column can be estimated. It is shown that single atom sensitivity is feasible taking the latter aspects into consideration.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000324474900005	Publication Date	2013-05-17
	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	48	Open Access
	Notes	FWO; Esteem2; FP 2007-2013; esteem2_jra2			Approved	Most recent IF: 2.843; 2013 IF: 2.745
	Call Number	UA @ lucian @ c:irua:109916			Serial	162
Permanent link to this record



	Author	Gonnissen, J.; De Backer, A.; den Dekker, A.J.; Sijbers, J.; Van Aert, S.
	Title	Atom-counting in High Resolution Electron Microscopy: TEM or STEM – that's the question			Type	A1 Journal article
	Year	2016	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	174	Issue	174	Pages	112-120
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	In this work, a recently developed quantitative approach based on the principles of detection theory is used in order to determine the possibilities and limitations of High Resolution Scanning Transmission Electron Microscopy (HR STEM) and HR TEM for atom-counting. So far, HR STEM has been shown to be an appropriate imaging mode to count the number of atoms in a projected atomic column. Recently, it has been demonstrated that HR TEM, when using negative spherical aberration imaging, is suitable for atom-counting as well. The capabilities of both imaging techniques are investigated and compared using the probability of error as a criterion. It is shown that for the same incoming electron dose, HR STEM outperforms HR TEM under common practice standards, i.e. when the decision is based on the probability function of the peak intensities in HR TEM and of the scattering cross-sections in HR STEM. If the atom-counting decision is based on the joint probability function of the image pixel values, the dependence of all image pixel intensities as a function of thickness should be known accurately. Under this assumption, the probability of error may decrease significantly for atom-counting in HR TEM and may, in theory, become lower as compared to HR STEM under the predicted optimal experimental settings. However, the commonly used standard for atom-counting in HR STEM leads to a high performance and has been shown to work in practice.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000403342200013	Publication Date	2016-10-27
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.843	Times cited	2	Open Access
	Notes	The authors gratefully acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0368.15N, G.0369.15N, G.0374.13N, and WO.010.16N) and a postdoctoral grant to A. De Backer. The research leading to these results has received funding from the European Union Seventh Framework Programme [FP7/2007-2013] under Grant agreement no. 312483 (ESTEEM2).			Approved	Most recent IF: 2.843
	Call Number	EMAT @ emat @ c:irua:137102			Serial	4315
Permanent link to this record



	Author	Bals, S.; Goris, B.; de Backer, A.; Van Aert, S.; Van Tendeloo, G.
	Title	Atomic resolution electron tomography			Type	A1 Journal article
	Year	2016	Publication	MRS bulletin	Abbreviated Journal	Mrs Bull
	Volume	41	Issue	41	Pages	525-530
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Over the last two decades, three-dimensional (3D) imaging by transmission electron microscopy or “electron tomography” has evolved into a powerful tool to investigate a variety of nanomaterials in different fields, such as life sciences, chemistry, solid-state physics, and materials science. Most of these results were obtained with nanometer-scale resolution, but different approaches have recently pushed the resolution to the atomic level. Such information is a prerequisite to understand the specific relationship between the atomic structure and the physicochemical properties of (nano) materials. We provide an overview of the latest progress in the field of atomic-resolution electron tomography. Different imaging and reconstruction approaches are presented, and state-of-the-art results are discussed. This article demonstrates the power and importance of electron tomography with atomic-scale resolution.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Pittsburgh, Pa	Editor
	Language		Wos	000382508100012	Publication Date	2016-07-07
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0883-7694	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	5.199	Times cited	19	Open Access	OpenAccess
	Notes	; The authors gratefully acknowledge funding from the Research Foundation Flanders (G.0381.16N, G.036915, G.0374.13, and funding of postdoctoral grants to B.G. and A.D.B.). S.B. acknowledges the European Research Council, ERC Grant Number 335078-Colouratom. The research leading to these results received funding from the European Union Seventh Framework Program under Grant Agreements 312483 (ESTEEM2). The authors would like to thank the colleagues who have contributed to this work, including K.J. Batenburg, J. De Beenhouwer, R. Erni, M.D. Rossell, W. Van den Broek, L. Liz-Marzan, E. Carbo-Argibay, S. Gomez-Grana, P. Lievens, M. Van Bael, B. Partoens, B. Schoeters, and J. Sijbers. ; ecas_sara			Approved	Most recent IF: 5.199
	Call Number	UA @ lucian @ c:irua:135690			Serial	4299
Permanent link to this record



	Author	Van Aert, S.; De Backer, A.; Jones, L.; Martinez, G.T.; Béché, A.; Nellist, P.D.
	Title	Control of Knock-On Damage for 3D Atomic Scale Quantification of Nanostructures: Making Every Electron Count in Scanning Transmission Electron Microscopy			Type	A1 Journal article
	Year	2019	Publication	Physical review letters	Abbreviated Journal	Phys Rev Lett
	Volume	122	Issue	6	Pages	066101
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Understanding nanostructures down to the atomic level is the key to optimizing the design of advancedmaterials with revolutionary novel properties. This requires characterization methods capable of quantifying the three-dimensional (3D) atomic structure with the highest possible precision. A successful approach to reach this goal is to count the number of atoms in each atomic column from 2D annular dark field scanning transmission electron microscopy images. To count atoms with single atom sensitivity, a minimum electron dose has been shown to be necessary, while on the other hand beam damage, induced by the high energy electrons, puts a limit on the tolerable dose. An important challenge is therefore to develop experimental strategies to optimize the electron dose by balancing atom-counting fidelity vs the risk of knock-on damage. To achieve this goal, a statistical framework combined with physics-based modeling of the dose-dependent processes is here proposed and experimentally verified. This model enables an investigator to theoretically predict, in advance of an experimental measurement, the optimal electron dose resulting in an unambiguous quantification of nanostructures in their native state with the highest attainable precision.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000458824200008	Publication Date	2019-02-13
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0031-9007	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	8.462	Times cited	3	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). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (WO.010.16N, G.0934.17N, G.0502.18N, G.0267.18N), and a grant to A. D. B. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement No. 312483— ESTEEM2 (Integrated Infrastructure Initiative-I3) and the UK EPSRC (Grant No. EP/M010708/1).			Approved	Most recent IF: 8.462
	Call Number	EMAT @ emat @UA @ admin @ c:irua:157175			Serial	5156
Permanent link to this record



	Author	Alania, M.; Altantzis, T.; De Backer, A.; Lobato, I.; Bals, S.; Van Aert, S.
	Title	Depth sectioning combined with atom-counting in HAADF STEM to retrieve the 3D atomic structure			Type	A1 Journal article
	Year	2016	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	177	Issue	177	Pages	36-42
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Aberration correction in scanning transmission electron microscopy (STEM) has greatly improved the lateral and depth resolution. When using depth sectioning, a technique during which a series of images is recorded at different defocus values, single impurity atoms can be visualised in three dimensions. In this paper, we investigate new possibilities emerging when combining depth sectioning and precise atom-counting in order to reconstruct nanosized particles in three dimensions. Although the depth resolution does not allow one to precisely locate each atom within an atomic column, it will be shown that the depth location of an atomic column as a whole can be measured precisely. In this manner, the morphology of a nanoparticle can be reconstructed in three dimensions. This will be demonstrated using simulations and experimental data of a gold nanorod.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000401219800006	Publication Date	2016-11-09
	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	2.843	Times cited	13	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. S. Bals acknowledges funding from the European Research Council (Starting Grant No. COLOURATOMS 335078). 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) and a post-doctoral grant to A. De Backer and T. Altantzis. The authors are grateful to Professor Luis M. Liz-Marzán for providing the sample.; ECAS_Sara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot);			Approved	Most recent IF: 2.843
	Call Number	EMAT @ emat @ c:irua:138015UA @ admin @ c:irua:138015			Serial	4316
Permanent link to this record



	Author	Gonnissen, J.; De Backer, A.; den Dekker, A.J.; Sijbers, J.; Van Aert, S.
	Title	Detecting and locating light atoms from high-resolution STEM images: The quest for a single optimal design			Type	A1 Journal article
	Year	2016	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	170	Issue	170	Pages	128-138
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	In the present paper, the optimal detector design is investigated for both detecting and locating light atoms from high resolution scanning transmission electron microscopy (HR STEM) images. The principles of detection theory are used to quantify the probability of error for the detection of light atoms from HR STEM images. To determine the optimal experiment design for locating light atoms, use is made of the so-called Cramer-Rao Lower Bound (CRLB). It is investigated if a single optimal design can be found for both the detection and location problem of light atoms. Furthermore, the incoming electron dose is optimised for both research goals and it is shown that picometre range precision is feasible for the estimation of the atom positions when using an appropriate incoming electron dose under the optimal detector settings to detect light atoms.
	Address	Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium. Electronic address: sandra.vanaert@uantwerpen.be
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Wos	000386925500014	Publication Date	2016-07-26
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.843	Times cited	6	Open Access
	Notes	The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0368.15, G.0369.15 and G.0374.13) and a postdoctoral research grant to A. De Backer. The research leading to these results has also received funding from the European Union Seventh Framework Programme [FP7/2007-2013] under Grant agreement no. 312483 (ESTEEM2). The authors would also like to thank A. Rosenauer for providing access to the STEMsim software and Gerardo T. Martinez for fruitful discussions.; esteem2_jra2			Approved	Most recent IF: 2.843
	Call Number	c:irua:135337 c:irua:135337			Serial	4128
Permanent link to this record



	Author	de Backer, A.; Martinez, G.T.; MacArthur, K.E.; Jones, L.; Béché, A.; Nellist, P.D.; Van Aert, S.
	Title	Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting			Type	A1 Journal article
	Year	2015	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	151	Issue	151	Pages	56-61
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000351237800008	Publication Date	2014-12-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.843	Times cited	29	Open Access
	Notes	312483 Esteem2; 278510 Vortex; Fwo G039311; G006410; G037413; esteem2ta; ECASJO;			Approved	Most recent IF: 2.843; 2015 IF: 2.436
	Call Number	c:irua:123927 c:irua:123927			Serial	753
Permanent link to this record



	Author	de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S.
	Title	Efficient fitting algorithm			Type	H2 Book chapter
	Year	2021	Publication	Advances in imaging and electron physics T2 – Advances in imaging and electron physics	Abbreviated Journal
	Volume		Issue		Pages	73-90
	Keywords	H2 Book chapter; Electron microscopy for materials research (EMAT)
	Abstract	An efficient model-based estimation algorithm is introduced to quantify the atomic column positions and intensities from atomic-resolution (scanning) transmission electron microscopy ((S)TEM) images. This algorithm uses the least squares estimator on image segments containing individual columns fully accounting for overlap between neighboring columns, enabling the analysis of a large field of view. To provide end-users with this well-established quantification method, a user friendly program, StatSTEM, is developed which is freely available under a GNU public license. In this chapter, this efficient algorithm is applied to three different nanostructures for which the analysis of a large field of view is required.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2021-03-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume	217	Series Issue		Edition
	ISSN		ISBN	978-0-12-824607-8; 1076-5670	Additional Links	UA library record
	Impact Factor		Times cited		Open Access	Not_Open_Access
	Notes	ERC Consolidator project funded by the European Union grant #770887 Picometrics			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:177528			Serial	6778
Permanent link to this record



	Author	De Backer, A.; Zhang, Z.; van den Bos, K.H.W.; Bladt, E.; Sánchez‐Iglesias, A.; Liz‐Marzán, L.M.; Nellist, P.D.; Bals, S.; Van Aert, S.
	Title	Element Specific Atom Counting at the Atomic Scale by Combining High Angle Annular Dark Field Scanning Transmission Electron Microscopy and Energy Dispersive X‐ray Spectroscopy			Type	A1 Journal article
	Year	2022	Publication	Small methods	Abbreviated Journal	Small Methods
	Volume		Issue		Pages	2200875
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	A new methodology is presented to count the number of atoms in multimetallic nanocrystals by combining energy dispersive X-ray spectroscopy (EDX) and high angle annular dark field scanning transmission electron microscopy (HAADF STEM). For this purpose, the existence of a linear relationship between the incoherent HAADF STEM and EDX images is exploited. Next to the number of atoms for each element in the atomic columns, the method also allows quantification of the error in the obtained number of atoms, which is of importance given the noisy nature of the acquired EDX signals. Using experimental images of an Au@Ag core–shell nanorod, it is demonstrated that 3D structural information can be extracted at the atomic scale. Furthermore, simulated data of an Au@Pt core–shell nanorod show the prospect to characterize heterogeneous nanostructures with adjacent atomic numbers.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000862072700001	Publication Date	2022-09-30
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2366-9608	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	12.4	Times cited	5	Open Access	OpenAccess
	Notes	This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S.V.A., Grant 815128 REALNANO to S.B., 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 a postdoctoral grant to A.D.B.; esteem3reported; esteem3JRA			Approved	Most recent IF: 12.4
	Call Number	EMAT @ emat @c:irua:191570			Serial	7109
Permanent link to this record



	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
	Impact Factor	2.2	Times cited		Open Access
	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 @			Serial	8996
Permanent link to this record



	Author	den Dekker, A.J.; Gonnissen, J.; de Backer, A.; Sijbers, J.; Van Aert, S.
	Title	Estimation of unknown structure parameters from high-resolution (S)TEM images : what are the limits?			Type	A1 Journal article
	Year	2013	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	134	Issue		Pages	34-43
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	Statistical parameter estimation theory is proposed as a quantitative method to measure unknown structure parameters from electron microscopy images. Images are then purely considered as data planes from which structure parameters have to be determined as accurately and precisely as possible using a parametric statistical model of the observations. For this purpose, an efficient algorithm is proposed for the estimation of atomic column positions and intensities from high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) images. Furthermore, the so-called CramérRao lower bound (CRLB) is reviewed to determine the limits to the precision with which continuous parameters such as atomic column positions and intensities can be estimated. Since this lower bound can only be derived for continuous parameters, alternative measures using the principles of detection theory are introduced for problems concerning the estimation of discrete parameters such as atomic numbers. An experimental case study is presented to show the practical use of these measures for the optimization of the experiment design if the purpose is to decide between the presence of specific atom types using STEM images.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000324474900006	Publication Date	2013-06-01
	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	2.843	Times cited	31	Open Access
	Notes	FWO; FP 2007-2013; Esteem2; esteem2_jra2			Approved	Most recent IF: 2.843; 2013 IF: 2.745
	Call Number	UA @ lucian @ c:irua:109240			Serial	1083
Permanent link to this record



	Author	Klingstedt, M.; Sundberg, M.; Eriksson, L.; Haigh, S.; Kirkland, A.; Grüner, D.; de Backer, A.; Van Aert, S.; Tarasaki, O.
	Title	Exit wave reconstruction from focal series of HRTEM images, single crystal XRD and total energy studies on Sb_xWO_3+y (x\sim0.11)			Type	A1 Journal article
	Year	2012	Publication	Zeitschrift für Kristallographie	Abbreviated Journal	Z Krist-Cryst Mater
	Volume	227	Issue	6	Pages	341-349
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	A new tungsten bronze in the SbWO system has been prepared in a solid state reaction from Sb2O3, WO3 and W metal powder. The average structure was determined by single crystal X-ray diffraction. SbxWO3+y (x ∼ 0.11) crystallizes in the orthorhombic space group Pm21n (no. 31), a = 27.8135(9) Å, b = 7.3659(2) Å and c = 3.8672(1) Å. The structure belongs to the (n)-ITB class of intergrowth tungsten bronzes. It contains slabs of hexagonal channels formed by six WO6 octahedra. These slabs are separated by three layers of WO6 octahedra that are arranged in a WO3-type fashion. The WO6 octahedra share all vertices to build up a three-dimensional framework. The hexagonal channels are filled with Sb atoms to ∼80% and additional O atoms. The atoms are shifted out of the center of the channels. Exit-wave reconstruction of focal series of high resolution-transmission-electron-microscope (HRTEM) images combined with statistical paramäeter estimation techniques allowed to study local ordering in the channels. Sb atoms in neighbouring channels tend to be displaced in the same direction, which is in agreement with total energy calculations on ordered structure models, but the ratio of the occupation of the two possible Sb sites varies from channel to channel. The structure of SbxWO3+y exhibits pronounced local modulations.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	München	Editor
	Language		Wos	000307314200003	Publication Date	2012-06-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2194-4946;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.179	Times cited	4	Open Access
	Notes	Fwo; Esteem 026019			Approved	Most recent IF: 3.179; 2012 IF: NA
	Call Number	UA @ lucian @ c:irua:101218			Serial	1131
Permanent link to this record



	Author	De Backer, A.; Van Aert, S.; Faes, C.; Arslan Irmak, E.; Nellist, P.D.; Jones, L.
	Title	Experimental reconstructions of 3D atomic structures from electron microscopy images using a Bayesian genetic algorithm			Type	A1 Journal article
	Year	2022	Publication	N P J Computational Materials	Abbreviated Journal	npj Comput Mater
	Volume	8	Issue	1	Pages	216
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We introduce a Bayesian genetic algorithm for reconstructing atomic models of monotype crystalline nanoparticles from a single projection using Z-contrast imaging. The number of atoms in a projected atomic column obtained from annular dark field scanning transmission electron microscopy images serves as an input for the initial three-dimensional model. The algorithm minimizes the energy of the structure while utilizing a priori information about the finite precision of the atom-counting results and neighbor-mass relations. The results show promising prospects for obtaining reliable reconstructions of beam-sensitive nanoparticles during dynamical processes from images acquired with sufficiently low incident electron doses.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000866500900001	Publication Date	2022-10-12
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2057-3960	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor		Times cited		Open Access	OpenAccess
	Notes	This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S.V.A. 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 a postdoctoral grant to A.D.B. L.J. acknowledges Science Foundation Ireland (SFI – grant number URF/RI/191637), the Royal Society, and the AMBER Centre. The authors acknowledge Aakash Varambhia for his assistance and expertise with the experimental recording and use of characterization facilities within the David Cockayne Centre for Electron Microscopy, Department of Materials, University of Oxford, and in particular the EPSRC (EP/K040375/1 South of England Analytical Electron Microscope).; esteem3reported; esteem3JRA			Approved	Most recent IF: NA
	Call Number	EMAT @ emat @c:irua:191398			Serial	7114
Permanent link to this record



	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
Permanent link to this record



	Author	de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S.
	Title	General conclusions and future perspectives			Type	H2 Book chapter
	Year	2021	Publication	Advances in imaging and electron physics T2 – Advances in imaging and electron physics	Abbreviated Journal
	Volume		Issue		Pages	243-253
	Keywords	H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	This chapter provides an overview of statistical and quantitative methodologies that have pushed (scanning) transmission electron microscopy ((S)TEM) toward accurate and precise measurements of unknown structure parameters for understanding the relation between the structure of a material and its properties. Hereby, statistical parameter estimation theory has extensively been used which enabled not only measuring atomic column positions, but also quantifying the number of atoms, and detecting atomic columns as accurately and precisely as possible from experimental images. As a general conclusion, it can be stated that advanced statistical techniques are ideal tools to perform quantitative electron microscopy at the atomic scale. In the future, statistical methods will continue to be developed and novel quantification procedures will open up new possibilities for studying material structures at the atomic scale.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2021-03-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume	217	Series Issue		Edition
	ISSN		ISBN	978-0-12-824607-8; 1076-5670	Additional Links	UA library record
	Impact Factor		Times cited		Open Access	Not_Open_Access
	Notes	ERC Consolidator project funded by the European Union grant #770887 Picometrics			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:177533			Serial	6781
Permanent link to this record



	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
Permanent link to this record



	Author	de Backer, A.; Van Aert, S.; van Dyck, D.
	Title	High precision measurements of atom column positions using model-based exit wave reconstruction			Type	A1 Journal article
	Year	2011	Publication	Ultramicroscopy	Abbreviated Journal	Ultramicroscopy
	Volume	111	Issue	9/10	Pages	1475-1482
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	In this paper, it has been investigated how to measure atom column positions as accurately and precisely as possible using a focal series of images. In theory, it is expected that the precision would considerably improve using a maximum likelihood estimator based on the full series of focal images. As such, the theoretical lower bound on the variances of the unknown atom column positions can be attained. However, this approach is numerically demanding. Therefore, maximum likelihood estimation has been compared with the results obtained by fitting a model to a reconstructed exit wave rather than to the full series of focal images. Hence, a real space model-based exit wave reconstruction technique based on the channelling theory is introduced. Simulations show that the reconstructed complex exit wave contains the same amount of information concerning the atom column positions as the full series of focal images. Only for thin samples, which act as weak phase objects, this information can be retrieved from the phase of the reconstructed complex exit wave.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000300461200004	Publication Date	2011-07-28
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0304-3991;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.843	Times cited	8	Open Access
	Notes	Fwo			Approved	Most recent IF: 2.843; 2011 IF: 2.471
	Call Number	UA @ lucian @ c:irua:91879			Serial	1438
Permanent link to this record



	Author	Alania, M.; De Backer, A.; Lobato, I.; Krause, F.F.; Van Dyck, D.; Rosenauer, A.; Van Aert, S.
	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	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
Permanent link to this record



	Author	De wael, A.; De Backer, A.; Jones, L.; Nellist, P.D.; Van Aert, S.
	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	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
Permanent link to this record



	Author	Fatermans, J.; de Backer, A.; den Dekker, A.J.; Van Aert, S.
	Title	Image-quality evaluation and model selection with maximum a posteriori probability			Type	H2 Book chapter
	Year	2021	Publication	Advances in imaging and electron physics T2 – Advances in imaging and electron physics	Abbreviated Journal
	Volume		Issue		Pages	215-242
	Keywords	H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	The maximum a posteriori (MAP) probability rule for atom column detection can also be used as a tool to evaluate the relation between scanning transmission electron microscopy (STEM) image quality and atom detectability. In this chapter, a new image-quality measure is proposed that correlates well with atom detectability, namely the integrated contrast-to-noise ratio (ICNR). Furthermore, the working principle of the MAP probability rule is described in detail showing a close relation to the principles of model-selection methods.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2021-03-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume	217	Series Issue		Edition
	ISSN		ISBN	978-0-12-824607-8; 1076-5670	Additional Links	UA library record
	Impact Factor		Times cited		Open Access	Not_Open_Access
	Notes	ERC Consolidator project funded by the European Union grant #770887 Picometrics			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:177532			Serial	6782
Permanent link to this record



	Author	Geuchies, J.J.; van Overbeek, C.; Evers, W.H.; Goris, B.; de Backer, A.; Gantapara, A.P.; Rabouw, F.T.; Hilhorst, J.; Peters, J.L.; Konovalov, O.; Petukhov, A.V.; Dijkstra, M.; Siebbeles, L.D.A.; van Aert, S.; Bals, S.; Vanmaekelbergh, D.
	Title	In situ study of the formation mechanism of two-dimensional superlattices from PbSe nanocrystals			Type	A1 Journal article
	Year	2016	Publication	Nature materials	Abbreviated Journal	Nat Mater
	Volume	15	Issue	15	Pages	1248-1254
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Oriented attachment of PbSe nanocubes can result in the formation of two-dimensional (2D) superstructures with long-range nanoscale and atomic order. This questions the applicability of classic models in which the superlattice grows by first forming a nucleus, followed by sequential irreversible attachment of nanocrystals, as one misaligned attachment would disrupt the 2D order beyond repair. Here, we demonstrate the formation mechanism of 2D PbSe superstructures with square geometry by using in situ grazing-incidence X-ray scattering (small angle and wide angle), ex situ electron microscopy, and Monte Carlo simulations. We observed nanocrystal adsorption at the liquid/gas interface, followed by the formation of a hexagonal nanocrystal monolayer. The hexagonal geometry transforms gradually through a pseudo-hexagonal phase into a phase with square order, driven by attractive interactions between the {100} planes perpendicular to the liquid substrate, which maximize facet-to-facet overlap. The nanocrystals then attach atomically via a necking process, resulting in 2D square superlattices.
	Address	Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Wos	000389104400011	Publication Date	2016-09-05
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1476-1122	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	39.737	Times cited	182	Open Access	OpenAccess
	Notes	This research is part of the programme ‘Designing Dirac Carriers in semiconductor honeycomb superlattices (DDC13),’ which is supported by the Foundation for Fundamental Research on Matter (FOM), which is part of the Dutch Research Council (NWO). J.J.G. acknowledges funding from the Debye and ESRF Graduate Programs. The authors gratefully acknowledge funding from the Research Foundation Flanders (G.036915 G.037413 and funding of postdoctoral grants to B.G. and A.d.B). S.B. acknowledges the European Research Council, ERC grant No 335078—Colouratom. The authors gratefully acknowledge I. Swart and M. van Huis for fruitful discussions. We acknowledge funding from NWO-CW TOPPUNT ‘Superficial Superstructures’. The X-ray scattering measurements were performed at the ID10 beamline at ESRF under proposal numbers SC-4125 and SC-3786. The authors thank G. L. Destri and F. Zontone for their support during the experiments.; ECAS_Sara; (ROMEO:yellow; preprint:; postprint:restricted ; pdfversion:cannot);			Approved	Most recent IF: 39.737
	Call Number	EMAT @ emat @ c:irua:136165			Serial	4289
Permanent link to this record



	Author	Hudry, D.; De Backer, A.; Popescu, R.; Busko, D.; Howard, I.A.; Bals, S.; Zhang, Y.; Pedrazo‐Tardajos, A.; Van Aert, S.; Gerthsen, D.; Altantzis, T.; Richards, B.S.
	Title	Interface Pattern Engineering in Core‐Shell Upconverting Nanocrystals: Shedding Light on Critical Parameters and Consequences for the Photoluminescence Properties			Type	A1 Journal article
	Year	2021	Publication	Small	Abbreviated Journal	Small
	Volume		Issue		Pages	2104441
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
	Abstract	Advances in controlling energy migration pathways in core-shell lanthanide (Ln)-based hetero-nanocrystals (HNCs) have relied heavily on assumptions about how optically active centers are distributed within individual HNCs. In this article, it is demonstrated that different types of interface patterns can be formed depending on shell growth conditions. Such interface patterns are not only identified but also characterized with spatial resolution ranging from the nanometer- to the atomic-scale. In the most favorable cases, atomic-scale resolved maps of individual particles are obtained. It is also demonstrated that, for the same type of core-shell architecture, the interface pattern can be engineered with thicknesses of just 1 nm up to several tens of nanometers. Total alloying between the core and shell domains is also possible when using ultra-small particles as seeds. Finally, with different types of interface patterns (same architecture and chemical composition of the core and shell domains) it is possible to modify the output color (yellow, red, and green-yellow) or change (improvement or degradation) the absolute upconversion quantum yield. The results presented in this article introduce an important paradigm shift and pave the way toward the emergence of a new generation of core-shell Ln-based HNCs with better control over their atomic-scale organization.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000710758000001	Publication Date	2021-10-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1613-6810	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	8.643	Times cited	17	Open Access	OpenAccess
	Notes	The authors would like to acknowledge the financial support provided by the Helmholtz Recruitment Initiative Fellowship (B.S.R.) and the Helmholtz Association's Research Field Energy (Materials and Technologies for the Energy Transition program, Topic 1 Photovoltaics and Wind Energy). The authors would like to thank the Karlsruhe Nano Micro Facility (KNMF) for STEM access. 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 PICOMETRICS to S.V.A. and Grant agreement no. 815128 REALNANO to S.B.). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through Projects no. G.0502.18N, G.0267.18N, and a postdoctoral grant to A.D.B. T.A. acknowledges funding from the University of Antwerp Research fund (BOF). This project had received funding (EUSMI proposal #E181100205) from the European Union's Horizon 2020 Research and Innovation Programme under Grant agreement no 731019 (EUSMI). D.H. would like to thank “CGFigures” for helpful tutorials on 3D graphics with Blender.; sygmaSB			Approved	Most recent IF: 8.643
	Call Number	EMAT @ emat @c:irua:183285			Serial	6817
Permanent link to this record



	Author	de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S.
	Title	Introduction			Type	H2 Book chapter
	Year	2021	Publication	Advances in imaging and electron physics T2 – Advances in imaging and electron physics	Abbreviated Journal
	Volume		Issue		Pages	1-28
	Keywords	H2 Book chapter; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2021-03-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume	217	Series Issue		Edition
	ISSN		ISBN	978-0-12-824607-8; 1076-5670	Additional Links	UA library record
	Impact Factor		Times cited		Open Access	Not_Open_Access
	Notes	ERC Consolidator project funded by the European Union grant #770887 Picometrics			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:177525			Serial	6784
Permanent link to this record



	Author	Goris, B.; De Beenhouwer, J.; de Backer, A.; Zanaga, D.; Batenburg, J.; Sanchez-Iglesias, A.; Liz-Marzan, L.; Van Aert, S.; Sijbers, J.; Van Tendeloo, G.; Bals, S.
	Title	Investigating lattice strain in Au nanodecahedrons			Type	P1 Proceeding
	Year	2016	Publication		Abbreviated Journal
	Volume		Issue		Pages	11-12
	Keywords	P1 Proceeding; Electron microscopy for materials research (EMAT); Vision lab
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2016-12-21
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	978-3-527-80846-5	ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access	Not_Open_Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ lucian @ c:irua:145813			Serial	5144
Permanent link to this record



	Author	Kirkwood, N.; De Backer, A.; Altantzis, T.; Winckelmans, N.; Longo, A.; Antolinez, F.V.; Rabouw, F.T.; De Trizio, L.; Geuchies, J.J.; Mulder, J.T.; Renaud, N.; Bals, S.; Manna, L.; Houtepen, A.J.
	Title	Locating and controlling the Zn content in In(Zn)P quantum dots			Type	A1 Journal article
	Year	2019	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	32	Issue	32	Pages	557-565
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Zinc is routinely employed in the synthesis of InP quantum dots (QDs) to improve the photoluminescence efficiency and carrier mobility of the resulting In(Zn)P alloy nanostructures. The exact location of Zn in the final structures and the mechanism by which it enhances the optoelectronic properties of the QDs is debated. We use synchrotron X-ray absorbance spectroscopy to show that the majority of Zn in In(Zn)P QDs is located at their surface as Zn-carboxylates. However, a small amount of Zn is present inside the bulk of the QDs with the consequent contraction of their lattice, as confirmed by combining high resolution high-angle annular dark-field imaging scanning transmission electron microscopy (HAADF-STEM) with statistical parameter estimation theory. We further demonstrate that the Zn content and its incorporation into the QDs can be tuned by the ligation of commonly employed Zn carboxylate precursors: the use of highly reactive Zn-acetate leads to the formation of undesired Zn3P2 and the final nanostructures being characterized by broad optical features, whereas Zn-carboxylates with longer carbon chains lead to InP crystals with much lower zinc content and narrow optical features. These results can explain the differences between structural and optical properties of In(Zn)P samples reported across the literature, and provide a rational method to tune the amount of Zn in InP nanocrystals and to drive the incorporation of Zn either as surface Zn-carboxylate, as a substitutional dopant inside the InP crystal lattice, or even predominantly as Zn3P2.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000507721600056	Publication Date	2019-12-13
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	39	Open Access	OpenAccess
	Notes	A.J.H. acknowledges support from the European Research Council Horizon 2020 ERC Grant Agreement No. 678004 (Doping on Demand). This research is supported by the Dutch Technology Foundation TTW, which is part of The Netherlands Organization for Scientific Research (NWO), and which is partly funded by Ministry of Economic Affairs. SB acknowledges funding from the European Research Council (grant 815128 REALNANO). The authors gratefully acknowledge funding from the Research Foundation Flanders (FWO, Belgium) through project funding G.0381.16N and a postdoctoral grant to A.D.B. AJH, LM and JM acknowledge support from the H2020 Collaborative Project TEQ (Grant No. 766900).; sygma			Approved	Most recent IF: 9.466
	Call Number	EMAT @ emat @c:irua:165234			Serial	5438
Permanent link to this record