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Author Zanaga, D.; Altantzis, T.; Sanctorum, J.; Freitag, B.; Bals, S. pdf  url
doi  openurl
  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  
Permanent link to this record
 

 
Author Martinez, G.T.; Jones, L.; de Backer, A.; Béché, A.; Verbeeck, J.; Van Aert, S.; Nellist, P.D. pdf  url
doi  openurl
  Title Quantitative STEM normalisation : the importance of the electron flux Type A1 Journal article
  Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 159 Issue 159 Pages 46-58  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Annular dark-field (ADF) scanning transmission electron microscopy (STEM) has become widely used in quantitative studies based on the opportunity to directly compare experimental and simulated images. This comparison merely requires the experimental data to be normalised and expressed in units of fractional beam-current. However, inhomogeneities in the response of electron detectors can complicate this normalisation. The quantification procedure becomes both experiment and instrument specific, requiring new simulations for the particular response of each instrument's detector, and for every camera-length used. This not only impedes the comparison between different instruments and research groups, but can also be computationally very time consuming. Furthermore, not all image simulation methods allow for the inclusion of an inhomogeneous detector response. In this work, we propose an alternative method for normalising experimental data in order to compare these with simulations that consider a homogeneous detector response. To achieve this, we determine the electron flux distribution reaching the detector by means of a camera-length series or a so-called atomic column cross-section averaged convergent beam electron diffraction (XSACBED) pattern. The result is then used to determine the relative weighting of the detector response. Here we show that the results obtained by this new electron flux weighted (EFW) method are comparable to the currently used method, while considerably simplifying the needed simulation libraries. The proposed method also allows one to obtain a metric that describes the quality of the detector response in comparison with the ideal detector response.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000366220000006 Publication Date 2015-08-01  
  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 27 Open Access  
  Notes 246791 Countatoms; 278510 Vortex; 312483 Esteem2; Fwo G036815; G036915; G037413; G004413; esteem2ta ECASJO; Approved Most recent IF: 2.843; 2015 IF: 2.436  
  Call Number c:irua:127293 c:irua:127293UA @ admin @ c:irua:127293 Serial 2762  
Permanent link to this record
 

 
Author Bladt, E.; Pelt, D.M.; Bals, S.; Batenburg, K.J. pdf  url
doi  openurl
  Title Electron tomography based on highly limited data using a neural network reconstruction technique Type A1 Journal article
  Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 158 Issue 158 Pages 81-88  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract Gold nanoparticles are studied extensively due to their unique optical and catalytical properties. Their exact shape determines the properties and thereby the possible applications. Electron tomography is therefore often used to examine the three-dimensional (3D) shape of nanoparticles. However, since the acquisition of the experimental tilt series and the 3D reconstructions are very time consuming, it is difficult to obtain statistical results concerning the 3D shape of nanoparticles. Here, we propose a new approach for electron tomography that is based on artificial neural networks. The use of a new reconstruction approach enables us to reduce the number of projection images with a factor of 5 or more. The decrease in acquisition time of the tilt series and use of an efficient reconstruction algorithm allows us to examine a large amount of nanoparticles in order to retrieve statistical results concerning the 3D shape.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000361574800011 Publication Date 2015-07-10  
  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 25 Open Access OpenAccess  
  Notes 335078 COLOURATOM; FWO; COST Action MP1207; 312483 ESTEEM2; esteem2jra4; ECASSara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); Approved Most recent IF: 2.843; 2015 IF: 2.436  
  Call Number c:irua:126675 c:irua:126675 Serial 988  
Permanent link to this record
 

 
Author van Aarle, W.; Palenstijn, W.J.; De Beenhouwer, J.; Altantzis, T.; Bals, S.; Batenburg, K.J.; Sijbers, J. pdf  url
doi  openurl
  Title The ASTRA Toolbox: A platform for advanced algorithm development in electron tomography Type A1 Journal article
  Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 157 Issue 157 Pages 35-47  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract We present the ASTRA Toolbox as an open platform for 3D image reconstruction in tomography. Most of the software tools that are currently used in electron tomography offer limited flexibility with respect to the geometrical parameters of the acquisition model and the algorithms used for reconstruction. The ASTRA Toolbox provides an extensive set of fast and flexible building blocks that can be used to develop advanced reconstruction algorithms, effectively removing these limitations. We demonstrate this flexibility, the resulting reconstruction quality, and the computational efficiency of this toolbox by a series of experiments, based on experimental dual-axis tilt series.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Wos 000361002400005 Publication Date 2015-05-06  
  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 562 Open Access OpenAccess  
  Notes The authors acknowledge financial support from the iMinds ICONMetroCT project,the IWT SBO Tom Food project and from the Netherlands Organisation for Scientific Research (NWO),Project no. 639.072.005. Networking support was provided by the EXTREMA COST Action MP 1207. Sara Bals acknowledges financial support from the European Research Council (ERC Starting Grant #335078 COLOURATOMS).; ECAS_Sara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); Approved Most recent IF: 2.843; 2015 IF: 2.436  
  Call Number c:irua:127834 Serial 3974  
Permanent link to this record
 

 
Author Krause, F.F.; Ahl, J.P.; Tytko, D.; Choi, P.P.; Egoavil, R.; Schowalter, M.; Mehrtens, T.; Müller-Caspary, K.; Verbeeck, J.; Raabe, D.; Hertkorn, J.; Engl, K.; Rosenauer, A. pdf  url
doi  openurl
  Title Homogeneity and composition of AlInGaN : a multiprobe nanostructure study Type A1 Journal article
  Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 156 Issue 156 Pages 29-36  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The electronic properties of quaternary AlInGaN devices significantly depend on the homogeneity of the alloy. The identification of compositional fluctuations or verification of random-alloy distribution is hence of grave importance. Here, a comprehensive multiprobe study of composition and compositional homogeneity is presented, investigating AlInGaN layers with indium concentrations ranging from 0 to 17 at% and aluminium concentrations between 0 and 39 at% employing high-angle annular dark field scanning electron microscopy (HAADF STEM), energy dispersive X-ray spectroscopy (EDX) and atom probe tomography (APT). EDX mappings reveal distributions of local concentrations which are in good agreement with random alloy atomic distributions. This was hence investigated with HAADF STEM by comparison with theoretical random alloy expectations using statistical tests. To validate the performance of these tests, HAADF STEM image simulations were carried out for the case of a random-alloy distribution of atoms and for the case of In-rich clusters with nanometer dimensions. The investigated samples, which were grown by metal-organic vapor phase epitaxy (MOVPE), were thereby found to be homogeneous on this nanometer scale. Analysis of reconstructions obtained from APT measurements yielded matching results. Though HAADF STEM only allows for the reduction of possible combinations of indium and aluminium concentrations to the proximity of isolines in the two-dimensional composition space. The observed ranges of composition are in good agreement with the EDX and APT results within the respective precisions.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000361001800006 Publication Date 2015-04-26  
  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 11 Open Access  
  Notes 312483 Esteem2; esteem2_ta Approved Most recent IF: 2.843; 2015 IF: 2.436  
  Call Number c:irua:126965 c:irua:126965UA @ admin @ c:irua:126965 Serial 1485  
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. pdf  url
doi  openurl
  Title Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting Type A1 Journal article
  Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 151 Issue 151 Pages 56-61  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000351237800008 Publication Date 2014-12-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited 29 Open Access  
  Notes 312483 Esteem2; 278510 Vortex; Fwo G039311; G006410; G037413; esteem2ta; ECASJO; Approved Most recent IF: 2.843; 2015 IF: 2.436  
  Call Number c:irua:123927 c:irua:123927 Serial 753  
Permanent link to this record
 

 
Author de Backer, A.; De wael, A.; Gonnissen, J.; Van Aert, S. pdf  url
doi  openurl
  Title Optimal experimental design for nano-particle atom-counting from high-resolution STEM images Type A1 Journal article
  Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 151 Issue 151 Pages 46-55  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract In the present paper, the principles of detection theory are used to quantify the probability of error for atom-counting from high resolution scanning transmission electron microscopy (HR STEM) images. Binary and multiple hypothesis testing have been investigated in order to determine the limits to the precision with which the number of atoms in a projected atomic column can be estimated. The probability of error has been calculated when using STEM images, scattering cross-sections or peak intensities as a criterion to count atoms. Based on this analysis, we conclude that scattering cross-sections perform almost equally well as images and perform better than peak intensities. Furthermore, the optimal STEM detector design can be derived for atom-counting using the expression for the probability of error. We show that for very thin objects LAADF is optimal and that for thicker objects the optimal inner detector angle increases.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000351237800007 Publication Date 2014-11-11  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited 24 Open Access  
  Notes 312483 Esteem2; Fwo G039311; G037413; esteem2_jra2 Approved Most recent IF: 2.843; 2015 IF: 2.436  
  Call Number c:irua:123926 c:irua:123926 Serial 2481  
Permanent link to this record
 

 
Author Guzzinati, G.; Clark, L.; Béché, A.; Juchtmans, R.; Van Boxem, R.; Mazilu, M.; Verbeeck, J. pdf  url
doi  openurl
  Title Prospects for versatile phase manipulation in the TEM : beyond aberration correction Type A1 Journal article
  Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 151 Issue 151 Pages 85-93  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract In this paper we explore the desirability of a transmission electron microscope in which the phase of the electron wave can be freely controlled. We discuss different existing methods to manipulate the phase of the electron wave and their limitations. We show how with the help of current techniques the electron wave can already be crafted into specific classes of waves each having their own peculiar properties. Assuming a versatile phase modulation device is feasible, we explore possible benefits and methods that could come into existence borrowing from light optics where the so-called spatial light modulators provide programmable phase plates for quite some time now. We demonstrate that a fully controllable phase plate building on Harald Rose׳s legacy in aberration correction and electron optics in general would open an exciting field of research and applications.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000351237800012 Publication Date 2014-10-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited 19 Open Access  
  Notes 278510 Vortex; Fwo; 312483 Esteem2; esteem2jra2; esteem2jra3 ECASJO_; Approved Most recent IF: 2.843; 2015 IF: 2.436  
  Call Number c:irua:121405 c:irua:121405UA @ admin @ c:irua:121405 Serial 2731  
Permanent link to this record
 

 
Author Van Eyndhoven, G.; Kurttepeli, M.; van Oers, C.J.; Cool, P.; Bals, S.; Batenburg, K.J.; Sijbers, J. pdf  url
doi  openurl
  Title Pore REconstruction and Segmentation (PORES) method for improved porosity quantification of nanoporous materials Type A1 Journal article
  Year 2015 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 148 Issue 148 Pages 10-19  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab; Laboratory of adsorption and catalysis (LADCA)  
  Abstract Electron tomography is currently a versatile tool to investigate the connection between the structure and properties of nanomaterials. However, a quantitative interpretation of electron tomography results is still far from straightforward. Especially accurate quantification of pore-space is hampered by artifacts introduced in all steps of the processing chain, i.e., acquisition, reconstruction, segmentation and quantification. Furthermore, most common approaches require subjective manual user input. In this paper, the PORES algorithm POre REconstruction and Segmentation is introduced; it is a tailor-made, integral approach, for the reconstruction, segmentation, and quantification of porous nanomaterials. The PORES processing chain starts by calculating a reconstruction with a nanoporous-specific reconstruction algorithm: the Simultaneous Update of Pore Pixels by iterative REconstruction and Simple Segmentation algorithm (SUPPRESS). It classifies the interior region to the pores during reconstruction, while reconstructing the remaining region by reducing the error with respect to the acquired electron microscopy data. The SUPPRESS reconstruction can be directly plugged into the remaining processing chain of the PORES algorithm, resulting in accurate individual pore quantification and full sample pore statistics. The proposed approach was extensively validated on both simulated and experimental data, indicating its ability to generate accurate statistics of nanoporous materials.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000345973000002 Publication Date 2014-08-23  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited 7 Open Access OpenAccess  
  Notes Colouratom; ECAS_Sara; (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); Approved Most recent IF: 2.843; 2015 IF: 2.436  
  Call Number c:irua:119083 Serial 2672  
Permanent link to this record
 

 
Author Chen, D.; Goris, B.; Bleichrodt, F.; Heidari Mezerji, H.; Bals, S.; Batenburg, K.J.; de With, G.; Friedrich, H. pdf  url
doi  openurl
  Title The properties of SIRT, TVM, and DART for 3D imaging of tubular domains in nanocomposite thin-films and sections Type A1 Journal article
  Year 2014 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 147 Issue Pages 137-148  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract In electron tomography, the fidelity of the 3D reconstruction strongly depends on the employed reconstruction algorithm. In this paper, the properties of SIRT, TVM and DART reconstructions are studied with respect to having only a limited number of electrons available for imaging and applying different angular sampling schemes. A well-defined realistic model is generated, which consists of tubular domains within a matrix having slab-geometry. Subsequently, the electron tomography workflow is simulated from calculated tilt-series over experimental effects to reconstruction. In comparison with the model, the fidelity of each reconstruction method is evaluated qualitatively and quantitatively based on global and local edge profiles and resolvable distance between particles. Results show that the performance of all reconstruction methods declines with the total electron dose. Overall, SIRT algorithm is the most stable method and insensitive to changes in angular sampling. TVM algorithm yields significantly sharper edges in the reconstruction, but the edge positions are strongly influenced by the tilt scheme and the tubular objects become thinned. The DART algorithm markedly suppresses the elongation artifacts along the beam direction and moreover segments the reconstruction which can be considered a significant advantage for quantification. Finally, no advantage of TVM and DART to deal better with fewer projections was observed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000343157400015 Publication Date 2014-08-19  
  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 42 Open Access OpenAccess  
  Notes Fwo Approved Most recent IF: 2.843; 2014 IF: 2.436  
  Call Number UA @ lucian @ c:irua:119073 Serial 2729  
Permanent link to this record
 

 
Author Egoavil, R.; Gauquelin, N.; Martinez, G.T.; Van Aert, S.; Van Tendeloo, G.; Verbeeck, J. pdf  url
doi  openurl
  Title Atomic resolution mapping of phonon excitations in STEM-EELS experiments Type A1 Journal article
  Year 2014 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 147 Issue Pages 1-7  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Atomically resolved electron energy-loss spectroscopy experiments are commonplace in modern aberration-corrected transmission electron microscopes. Energy resolution has also been increasing steadily with the continuous improvement of electron monochromators. Electronic excitations however are known to be delocalized due to the long range interaction of the charged accelerated electrons with the electrons in a sample. This has made several scientists question the value of combined high spatial and energy resolution for mapping interband transitions and possibly phonon excitation in crystals. In this paper we demonstrate experimentally that atomic resolution information is indeed available at very low energy losses around 100 meV expressed as a modulation of the broadening of the zero loss peak. Careful data analysis allows us to get a glimpse of what are likely phonon excitations with both an energy loss and gain part. These experiments confirm recent theoretical predictions on the strong localization of phonon excitations as opposed to electronic excitations and show that a combination of atomic resolution and recent developments in increased energy resolution will offer great benefit for mapping phonon modes in real space.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000343157400001 Publication Date 2014-05-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited 22 Open Access  
  Notes 246102 IFOX; 278510 VORTEX; 246791 COUNTATOMS; Hercules; 312483 ESTEEM2; esteem2jra3 ECASJO; Approved Most recent IF: 2.843; 2014 IF: 2.436  
  Call Number UA @ lucian @ c:irua:118332UA @ admin @ c:irua:118332 Serial 177  
Permanent link to this record
 

 
Author Van den Broek, W.; Rosenauer, A.; Van Aert, S.; Sijbers, J.; van Dyck, D. pdf  url
doi  openurl
  Title A memory efficient method for fully three-dimensional object reconstruction with HAADF STEM Type A1 Journal article
  Year 2014 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 141 Issue Pages 22-31  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract The conventional approach to object reconstruction through electron tomography is to reduce the three-dimensional problem to a series of independent two-dimensional slice-by-slice reconstructions. However, at atomic resolution the image of a single atom extends over many such slices and incorporating this image as prior knowledge in tomography or depth sectioning therefore requires a fully three-dimensional treatment. Unfortunately, the size of the three-dimensional projection operator scales highly unfavorably with object size and readily exceeds the available computer memory. In this paper, it is shown that for incoherent image formation the memory requirement can be reduced to the fundamental lower limit of the object size, both for tomography and depth sectioning. Furthermore, it is shown through multislice calculations that high angle annular dark field scanning transmission electron microscopy can be sufficiently incoherent for the reconstruction of single element nanocrystals, but that dynamical diffraction effects can cause classification problems if more than one element is present. (C) 2014 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000335766600004 Publication Date 2014-03-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited 6 Open Access  
  Notes ResearchFoundationFlanders(FWO;G.0393.11; G.0064.10;andG.0374.13); European Union Seventh Frame- workProgramme [FP7/2007-2013]under Grant agreement no. 312483 (ESTEEM2).; esteem2jra2; esteem2jra4 Approved Most recent IF: 2.843; 2014 IF: 2.436  
  Call Number UA @ lucian @ c:irua:117650 Serial 1992  
Permanent link to this record
 

 
Author Dunin-Borkowski, R.E.; Lichte, H.; Tillmann, K.; Van Aert, S.; Van Tendeloo, G. pdf  url
doi  openurl
  Title Introduction to a special issue in honour of W. Owen Saxton, David J. Smith and Dirk Van Dyck on the occasion of their 65th birthdays Type Editorial
  Year 2013 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 134 Issue Pages 1-1  
  Keywords Editorial; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Elsevier science bv Place of Publication Amsterdam Editor  
  Language Wos 000324474900001 Publication Date 2013-07-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited 1 Open Access  
  Notes Approved Most recent IF: 2.843; 2013 IF: 2.745  
  Call Number UA @ lucian @ c:irua:109917 Serial 1721  
Permanent link to this record
 

 
Author Schattschneider, P.; Löffler, S.; Stöger-Pollach, M.; Verbeeck, J. pdf  url
doi  openurl
  Title Is magnetic chiral dichroism feasible with electron vortices? Type A1 Journal article
  Year 2014 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 136 Issue Pages 81-85  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract We discuss the feasibility of detecting magnetic transitions with focused electron vortex probes, suggested by selection rules for the magnetic quantum number. We theoretically estimate the dichroic signal strength in the L2,3 edge of ferromagnetic d metals. It is shown that under realistic conditions, the dichroic signal is undetectable for nanoparticles larger than View the MathML source. This is confirmed by a key experiment with nanometer-sized vortices.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000327884700011 Publication Date 2013-07-26  
  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 64 Open Access  
  Notes Countatoms; Vortex; Esteem2; esteem2jra3 ECASJO; Approved Most recent IF: 2.843; 2014 IF: 2.436  
  Call Number UA @ lucian @ c:irua:110952UA @ admin @ c:irua:110952 Serial 1750  
Permanent link to this record
 

 
Author Heidari, H.; van den Broek, W.; Bals, S. pdf  url
doi  openurl
  Title Quantitative electron tomography : the effect of the three-dimensional point spread function Type A1 Journal article
  Year 2013 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 135 Issue Pages 1-5  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The intensity levels in a three-dimensional (3D) reconstruction, obtained by electron tomography, can be influenced by several experimental imperfections. Such artifacts will hamper a quantitative interpretation of the results. In this paper, we will correct for artificial intensity variations by determining the 3D point spread function (PSF) of a tomographic reconstruction based on high angle annular dark field scanning transmission electron microscopy. The large tails of the PSF cause an underestimation of the intensity of smaller particles, which in turn hampers an accurate radius estimate. Here, the error introduced by the PSF is quantified and corrected a posteriori.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000326941500001 Publication Date 2013-06-21  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited 6 Open Access  
  Notes Esteem2; Sunflower; esteem2_jra4 Approved Most recent IF: 2.843; 2013 IF: 2.745  
  Call Number UA @ lucian @ c:irua:111397 Serial 2756  
Permanent link to this record
 

 
Author Wang, A.; Turner, S.; Van Aert, S.; van Dyck, D. pdf  url
doi  openurl
  Title An alternative approach to determine attainable resolution directly from HREM images Type A1 Journal article
  Year 2013 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 133 Issue Pages 50-61  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract The concept of resolution in high-resolution electron microscopy (HREM) is the power to resolve neighboring atoms. Since the resolution is related to the width of the point spread function of the microscope, it could in principle be determined from the image of a point object. However, in electron microscopy there are no ideal point objects. The smallest object is an individual atom. If the width of an atom is much smaller than the resolution of the microscope, this atom can still be considered as a point object. As the resolution of the microscope enters the sub-Å regime, information about the microscope is strongly entangled with the information about the atoms in HREM images. Therefore, we need to find an alternative method to determine the resolution in an object-independent way. In this work we propose to use the image wave of a crystalline object in zone axis orientation. Under this condition, the atoms of a column act as small lenses so that the electron beam channels through the atom column periodically. Because of this focusing, the image wave of the column can be much more peaked than the constituting atoms and can thus be a much more sensitive probe to measure the resolution. Our approach is to use the peakiness of the image wave of the atom column to determine the resolution. We will show that the resolution can be directly linked to the total curvature of the atom column wave. Moreover, we can then directly obtain the resolution of the microscope given that the contribution from the object is known, which is related to the bounding energy of the atom. The method is applied on an experimental CaTiO3 image wave.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000324471800007 Publication Date 2013-05-23  
  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 2.843 Times cited Open Access  
  Notes FWO; Hercules; Esteem2; esteem2_jra2 Approved Most recent IF: 2.843; 2013 IF: 2.745  
  Call Number UA @ lucian @ c:irua:109919 Serial 90  
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Author de Backer, A.; Martinez, G.T.; Rosenauer, A.; Van Aert, S. pdf  url
doi  openurl
  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  
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Author Goris, B.; Roelandts, T.; Batenburg, K.J.; Heidari Mezerji, H.; Bals, S. pdf  url
doi  openurl
  Title Advanced reconstruction algorithms for electron tomography : from comparison to combination Type A1 Journal article
  Year 2013 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 127 Issue Pages 40-47  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract In this work, the simultaneous iterative reconstruction technique (SIRT), the total variation minimization (TVM) reconstruction technique and the discrete algebraic reconstruction technique (DART) for electron tomography are compared and the advantages and disadvantages are discussed. Furthermore, we describe how the result of a three dimensional (3D) reconstruction based on TVM can provide objective information that is needed as the input for a DART reconstruction. This approach results in a tomographic reconstruction of which the segmentation is carried out in an objective manner.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000316659100007 Publication Date 2012-08-02  
  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 2.843 Times cited 63 Open Access  
  Notes Fwo Approved Most recent IF: 2.843; 2013 IF: 2.745  
  Call Number UA @ lucian @ c:irua:101217 Serial 72  
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Author Schattschneider, P.; Verbeeck, J. pdf  url
doi  openurl
  Title Theory of free electron vortices Type A1 Journal article
  Year 2011 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 111 Issue 9/10 Pages 1461-1468  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The recent creation of electron vortex beams and their first practical application motivates a better understanding of their properties. Here, we develop the theory of free electron vortices with quantized angular momentum, based on solutions of the Schrödinger equation for cylindrical boundary conditions. The principle of transformation of a plane wave into vortices with quantized angular momentum, their paraxial propagation through round magnetic lenses, and the effect of partial coherence are discussed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000300461200002 Publication Date 2011-07-26  
  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 57 Open Access  
  Notes Esteem 026019 Approved Most recent IF: 2.843; 2011 IF: 2.471  
  Call Number UA @ lucian @ c:irua:91882 Serial 3617  
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Author de Backer, A.; Van Aert, S.; van Dyck, D. pdf  url
doi  openurl
  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  
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Author Lumbeeck, G.; Delvaux, A.; Idrissi, H.; Proost, J.; Schryvers, D. url  doi
openurl 
  Title Analysis of internal stress build-up during deposition of nanocrystalline Ni thin films using transmission electron microscopy Type A1 Journal article
  Year 2020 Publication Thin solid films : an international journal on the science and technology of thin and thick films Abbreviated Journal Thin Solid Films  
  Volume 707 Issue Pages 138076  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Ni thin films sputter-deposited at room temperature with varying Ar pressures were investigated with automated crystal orientation mapping in a transmission electron microscope to uncover the mechanisms controlling the internal stress build-up recorded in-situ during deposition. Large grains were found to induce behaviour similar to a stress-free nucleation layer. The measurements of grain size in most of the Ni thin films are in agreement with the island coalescence model. Low internal stress was observed at low Ar pressure and was explained by the presence of large grains. Relaxation of high internal stress was also noticed at the highest Ar pressure, which was attributed to a decrease of Σ3 twin boundary density due to a low deposition rate. The results provide insightful information to better understand the relationship between structural boundaries and the evolution of internal stress upon deposition of thin films.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000539312200011 Publication Date 2020-05-12  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 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 Hercules Foundation [Grant No. AUHA13009], the Flemish Research Fund (FWO) [Grant No. G.0365.15N], and the Flemish Strategic Initiative for Materials (SIM) under the project InterPoCo. Thin film deposition has been realised as part of the WallonHY project, funded by the Public Service of Wallonia – Department of Energy and Sustainable Building. H. Idrissi is mandated by the Belgian National Fund for Scientific Research (FSR-FNRS). Approved Most recent IF: NA  
  Call Number EMAT @ emat @c:irua:169708 Serial 6370  
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Author Chizhov, A.S.; Rumyantseva, M.N.; Vasiliev, R.B.; Filatova, D.G.; Drozdov, K.A.; Krylov, I.V.; Marchevsky, A.V.; Karakulina, O.M.; Abakumov, A.M.; Gaskov, A.M. pdf  url
doi  openurl
  Title Visible light activation of room temperature NO2 gas sensors based on ZnO, SnO2 and In2O3 sensitized with CdSe quantum dots Type A1 Journal article
  Year 2016 Publication Thin solid films : an international journal on the science and technology of thin and thick films Abbreviated Journal Thin Solid Films  
  Volume 618 Issue 618 Pages 253-262  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract This work reports the analysis of visible light activation of room temperature NO2 gas sensitivity of metal oxide semiconductors (MOS): blank and CdSe quantum dots (QDs) sensitized nanocrystallinematrixes ZnO, SnO2 and In2O3. Nanocrystalline metal oxides (MOx) ZnO, SnO2, In2O3 were synthesized by the precipitation method. Colloidal CdSe QDs were obtained by high temperature colloidal synthesis. Sensitization was effectuated by direct adsorption of CdSe QDs stabilized with oleic acid on MOx surface. The role of illumination consists in generation of electrons, which can be transferred into MOx conduction band, and holes that can recombine with the electrons previously trapped by the chemisorbed acceptor species and thus activate desorption of analyte molecules. Under green light illumination for blank SnO2 and In2O3 matrixes the indirect consequential mechanism for the generation of holes is proposed. Anothermechanismis realized in the presence of CdSe QDs. In this case the electron-hole pair is generated in the CdSe quantum dot. Sensor measurements demonstrated that synthesizedmaterials can be used for NO2 detection under visible (green) light illumination at room temperature without any thermal heating.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000389164400005 Publication Date 2016-09-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0040-6090 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.879 Times cited 19 Open Access  
  Notes The work was financially supported by Russian Foundation for Basic Research grant no. 15-03-03026. Approved Most recent IF: 1.879  
  Call Number EMAT @ emat @ c:irua:138598 Serial 4321  
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Author Vladimirova, N.V.; Frolov, A.S.; Sanchez-Barriga, J.; Clark, O.J.; Matsui, F.; Usachov, D.Y.; Muntwiler, M.; Callaert, C.; Hadermann, J.; Neudachina, V.S.; Tamm, M.E.; Yashina, L.V. pdf  url
doi  openurl
  Title Occupancy of lattice positions probed by X-ray photoelectron diffraction : a case study of tetradymite topological insulators Type A1 Journal article
  Year 2023 Publication Surfaces and interfaces Abbreviated Journal  
  Volume 36 Issue Pages 102516-10  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Occupancy of different structural positions in a crystal lattice often seems to play a key role in material prop-erties. Several experimental techniques have been developed to uncover this issue, all of them being mostly bulk sensitive. However, many materials including topological insulators (TIs), which are among the most intriguing modern materials, are intended to be used in devices as thin films, for which the sublattice occupancy may differ from the bulk. One of the possible approaches to occupancy analysis is X-ray Photoelectron Diffraction (XPD), a structural method in surface science with chemical sensitivity. We applied this method in a case study of Sb2(Te1-xSex)3 mixed crystals, which belong to prototypical TIs. We used high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) as a reference method to verify our analysis. We revealed that the XPD data for vacuum cleaved bulk crystals are in excellent agreement with the reference ones. Also, we demonstrate that the anion occupancy near a naturally formed surface can be rather different from that of the bulk. The present results are relevant for a wide range of compositions where the system remains a topological phase, as we ultimately show by probing the transiently occupied topological surface state above the Fermi level by ultrafast photoemission.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000901694900001 Publication Date 2022-11-28  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2468-0230 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 6.2 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 6.2; 2023 IF: NA  
  Call Number UA @ admin @ c:irua:193502 Serial 7327  
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Author Sharp, J.; Mueller, I.C.; Mandal, P.; Abbas, A.; Nord, M.; Doye, A.; Ehiasarian, A.; Hovsepian, P.; MacLaren, I.; Rainforth, W.M. url  doi
openurl 
  Title Characterisation of a high-power impulse magnetron sputtered C/Mo/W wear resistant coating by transmission electron microscopy Type A1 Journal article
  Year 2019 Publication Surface and coatings technology Abbreviated Journal Surf Coat Tech  
  Volume 377 Issue 377 Pages 124853  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Thin films of C/Mo/W deposited using combined UBM/HIPIMS sputtering show 2-8 nm clusters of material richer in Mo and W than the matrix (found by EDS microanalysis), with structures that resemble graphitic onions with the metal atoms arranged regularly within them. EELS microanalysis showed the clusters to be rich in W and Mo. As the time averaged power used in the pulsed HIPIMS magnetron was increased, the clusters became more defined, larger, and arranged into layers with amorphous matrix between them. Films deposited with average HIPIMS powers of 4 kW and 6 kW also showed a periodic modulation of the cluster density within the finer layers giving secondary, wider stripes in TEM. By analysing the ratio between the finer and coarser layers, it was found that this meta-layering is related to the substrate rotation in the deposition chamber but in a non-straightforward way. Reasons for this are proposed. The detailed structure of the clusters remains unknown and is the subject of further work. Fluctuation electron microscopy results indicated the presence of crystal planes with the graphite interlayer spacing, crystal planes in hexagonal WC perpendicular to the basal plane, and some plane spacings found in Mo2C. Other peaks in the FEM results suggested symmetry-related starting points for future determination of the structure of the clusters.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000488417800015 Publication Date 2019-08-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0257-8972 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.589 Times cited 1 Open Access  
  Notes ; J.S. thanks the Mercury Centre at the University of Sheffield for funding, which was part funded by the ERDF under grant MERCURY 904467. I.C.M. acknowledges support from CONACyT and RobertoRocca Education Fellowship. We gratefully acknowledge funding from EPSRC for the pixelated STEM detector and the software used in its operation for the fluctuation microscopy (EP/M009963/ 1, EP/K503903/1 & EP/R511705/1). AD was supported by the EPSRC CDT in Integrative Sensing and Measurement, Grant Number EP/L016753/1. Funding sources did not influence the planning or execution of this work except to enable it. ; Approved Most recent IF: 2.589  
  Call Number UA @ admin @ c:irua:163700 Serial 5383  
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Author Cremers, V.; Rampelberg, G.; Barhoum, A.; Walters, P.; Claes, N.; Oliveira, T.M. de; Assche, G.V.; Bals, S.; Dendooven, J.; Detavernier, C. pdf  url
doi  openurl
  Title Oxidation barrier of Cu and Fe powder by Atomic Layer Deposition Type A1 Journal article
  Year 2018 Publication Surface and coatings technology Abbreviated Journal Surf Coat Tech  
  Volume 349 Issue 349 Pages 1032-1041  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Atomic layer deposition (ALD) is a vapor based technique which allows to deposit uniform, conformal films with a thickness control at the atomic scale. In this research, Al 2 O 3 coatings were deposited on micrometer-sized Fe and Cu powder (particles) using the thermal trimethylaluminum (TMA)/ water (H 2 O) process in a rotary pump-type ALD reactor. Rotation of the powder during deposition was required to obtain a pinhole-free ALD coating. The protective nature of the coating was evaluated by quantifying its effectiveness in protecting the metal particles during oxidative annealing treatments. The Al 2 O 3 coated powders were annealed in ambient air while in-situ thermogravimetric analysis (TGA) and in-situ x-ray diffraction (XRD) data were acquired. The thermal stability of a series of Cu and Fe powder with different Al 2 O 3 thicknesses were determined with TGA. In both samples a clear shift in oxidation temperature is visible. For Cu and Fe powder coated with 25 nm Al 2 O 3 , we observed an increase of the oxidation temperature with 300-400°C. For the Cu powder a thin film of only 8 nm is required to obtain an initial increase in oxidation temperature of 200°C. In contrast, for Fe powder a thicker coating of 25 nm is required. In both cases, the oxidation temperature increases with increasing thickness of the Al 2 O 3 coating. These results illustrate that the Al 2 O 3 thin film, deposited by the thermal ALD process (TMA/H 2 O) can be an efficient and pinhole-free barrier layer for micrometer-sized powder particles, provided that the powder is properly agitated during the process to ensure sufficient vapour-solid interaction.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000441492600108 Publication Date 2018-06-25  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0257-8972 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.589 Times cited 10 Open Access OpenAccess  
  Notes The authors acknowledge financial support from the Strategic Initiative Materials in Flanders (SIM, SBO-FUNC project) and the Special Research Fund BOF of Ghent University (GOA 01G01513). J. D. acknowledges the Research Foundation Flanders (FWO-Vlaanderen) for a postdoctoral fellowship. N.C. and S.B. acknowledge financial support from European Research Council (ERC Starting Grant 335078-COLOURATOMS). The authors acknowledge S. Goeteyn for the assistance in preliminary depositions. (ROMEO:green; preprint:; postprint:can ; pdfversion:cannot); ecas_sara Approved Most recent IF: 2.589  
  Call Number EMAT @ emat @c:irua:152174UA @ admin @ c:irua:152174 Serial 4994  
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Author Saniz, R.; Bekaert, J.; Partoens, B.; Lamoen, D. pdf  url
doi  openurl
  Title First-principles study of defects at Σ3 grain boundaries in CuGaSe2 Type A1 Journal article
  Year 2021 Publication Solid State Communications Abbreviated Journal Solid State Commun  
  Volume Issue Pages 114263  
  Keywords A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)  
  Abstract We present a first-principles computational study of cation–Se 3 (112) grain boundaries in CuGaSe. We discuss the structure of these grain boundaries, as well as the effect of native defects and Na impurities on their electronic properties. The formation energies show that the defects will tend to form preferentially at the grain boundaries, rather than in the grain interiors. We find that in Ga-rich growth conditions Cu vacancies as well as Ga at Cu and Cu at Ga antisites are mainly responsible for having the equilibrium Fermi level pinned toward the middle of the gap, resulting in carrier depletion. The Na at Cu impurity in its +1 charge state contributes to this. In Ga-poor growth conditions, on the other hand, the formation energies of Cu vacancies and Ga at Cu antisites are comparatively too high for any significant influence on carrier density or on the equilibrium Fermi level position. Thus, under these conditions, the Cu at Ga antisites give rise to a -type grain boundary. Also, their formation energy is lower than the formation energy of Na at Cu impurities. Thus, the latter will fail to act as a hole barrier preventing recombination at the grain boundary, in contrast to what occurs in CuInSe grain boundaries. We also discuss the effect of the defects on the electronic properties of bulk CuGaSe, which we assume reflect the properties of the grain interiors.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000652668500013 Publication Date 2021-03-12  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0038-1098 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.554 Times cited 1 Open Access OpenAccess  
  Notes Fwo; We acknowledge the financial support of FWO-Vlaanderen, Belgium through project G.0150.13. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by FWO-Vlaanderen and the Flemish Government-department EWI. Approved Most recent IF: 1.554  
  Call Number EMAT @ emat @c:irua:176544 Serial 6703  
Permanent link to this record
 

 
Author Govaerts, K.; Partoens, B.; Lamoen, D. pdf  url
doi  openurl
  Title Extended homologous series of Sn–O layered systems: A first-principles study Type A1 Journal article
  Year 2016 Publication Solid state communications Abbreviated Journal Solid State Commun  
  Volume 243 Issue 243 Pages 36-43  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)  
  Abstract Apart from the most studied tin-oxide compounds, SnO and SnO2, intermediate states have been claimed to exist for more than a hundred years. In addition to the known homologous series (Seko et al., Phys. Rev. Lett. 100, 045702 (2008)), we here predict the existence of several new compounds with an O concentration between 50 % (SnO) and 67 % (SnO2). All these intermediate compounds are constructed from removing one or more (101) oxygen layers of SnO2. Since the van der Waals (vdW) interaction is known to be important for the Sn-Sn interlayer distances, we use a vdW-corrected functional, and compare these results with results obtained with PBE and hybrid functionals. We present the electronic properties of the intermediate structures and we observe a decrease of the band gap when (i) the O concentration increases and (ii) more SnO-like units are present for a given concentration. The contribution of the different atoms to the valence and conduction band is also investigated.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000381544200007 Publication Date 2016-06-12  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0038-1098 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.554 Times cited 10 Open Access  
  Notes We gratefully acknowledge financial support from a GOA fund of the University of Antwerp. K.G. thanks the University of Antwerp for a PhD fellowship. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the Hercules Foundation and the Flemish Government – department EWI. Approved Most recent IF: 1.554  
  Call Number c:irua:134037 Serial 4085  
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Author Khelifi, S.; Brammertz, G.; Choubrac, L.; Batuk, M.; Yang, S.; Meuris, M.; Barreau, N.; Hadermann, J.; Vrielinck, H.; Poelman, D.; Neyts, K.; Vermang, B.; Lauwaert, J. pdf  url
doi  openurl
  Title The path towards efficient wide band gap thin-film kesterite solar cells with transparent back contact for viable tandem application Type A1 Journal article
  Year 2021 Publication Solar Energy Materials And Solar Cells Abbreviated Journal Sol Energ Mat Sol C  
  Volume 219 Issue Pages 110824  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Wide band gap thin-film kesterite solar cell based on non-toxic and earth-abundant materials might be a suitable candidate as a top cell for tandem configuration in combination with crystalline silicon as a bottom solar cell. For this purpose and based on parameters we have extracted from electrical and optical characterization techniques of Cu2ZnGeSe4 absorbers and solar cells, a model has been developed to describe the kesterite top cell efficiency limitations and to investigate the different possible configurations with transparent back contact for fourterminal tandem solar cell application. Furthermore, we have studied the tandem solar cell performance in view of the band gap and the transparency of the kesterite top cell and back contact engineering. Our detailed analysis shows that a kesterite top cell with efficiency > 14%, a band gap in the range of 1.5-1.7 eV and transparency above 80% at the sub-band gaps photons energies are required to achieve a tandem cell with higher efficiency than with a single silicon solar cell.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000591683500002 Publication Date 2020-10-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0927-0248 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.784 Times cited Open Access OpenAccess  
  Notes The authors would like to acknowledge the SWInG project financed by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 640868 and the Research Foundation Flanders-Hercules Foundation (FWO-Vlaanderen, project No AUGE/13/16:FT-IMAGER). Approved Most recent IF: 4.784  
  Call Number EMAT @ emat @c:irua:174337 Serial 6706  
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Author Erfurt, D.; Koida, T.; Heinemann, M.D.; Li, C.; Bertram, T.; Nishinaga, J.; Szyszka, B.; Shibata, H.; Klenk, R.; Schlatmann, R. url  doi
openurl 
  Title Impact of rough substrates on hydrogen-doped indium oxides for the application in CIGS devices Type A1 Journal article
  Year 2020 Publication Solar Energy Materials And Solar Cells Abbreviated Journal Sol Energ Mat Sol C  
  Volume 206 Issue Pages 110300  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Indium oxide based transparent conductive oxides (TCOs) are promising contact layers in solar cells due to their outstanding electrical and optical properties. However, when applied in Cu(In,Ga)Se-2 or Si-hetero-junction solar cells the specific roughness of the material beneath can affect the growth and the properties of the TCO. We investigated the electrical properties of hydrogen doped and hydrogen-tungsten co-doped indium oxides grown on rough Cu(In,Ga)Se-2 samples as well as on textured and planar glass. At sharp ridges and V-shaped valleys crack-shaped voids form inside the indium oxide films, which limit the effective electron mobility of the In2O3:H and In2O3:H,W thin films. This was found for films deposited by magnetron sputtering and reactive plasma deposition at several deposition parameters, before as well as after annealing and solid phase crystallization. This suggests universal behavior that will have a wide impact on solar cell devices.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000519653800038 Publication Date 2019-11-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0927-0248 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 6.9 Times cited 5 Open Access OpenAccess  
  Notes ; This work was supported by the German Federal Ministry for Economic Affairs and Energy under contract number 0325762G (TCO4CIGS). The authors thank M. Hartig, K. Mayer-Stillrich, I. Dorbandt, B. Bunn, M. Kirsch for technical support. C. Li is grateful for financial support from Max Planck Society, Germany and technical support from the MPI FKF StEM group members. ; Approved Most recent IF: 6.9; 2020 IF: 4.784  
  Call Number UA @ admin @ c:irua:168668 Serial 6544  
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Author D'Olieslaeger, L.; Pfannmöller, M.; Fron, E.; Cardinaletti, I.; Van der Auweraer, M.; Van Tendeloo, G.; Bals, S.; Maes, W.; Vanderzande, D.; Manca, J.; Ethirajan, A. pdf  url
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  Title Tuning of PCDTBT : PC71BM blend nanoparticles for eco-friendly processing of polymer solar cells Type A1 Journal article
  Year 2017 Publication Solar energy materials and solar cells Abbreviated Journal Sol Energ Mat Sol C  
  Volume 159 Issue 159 Pages 179-188  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract We report the controlled preparation of water processable nanoparticles (NPs) employing the push-pull polymer PCDTBT and the fullerene acceptor PC71BM in order to enable solar cell processing using eco-friendly solvent (i.e. water). The presented method provides the possibility to separate the formation of the active layer blend and the deposition of the active layer into two different processes. For the first time, the benefits of aqueous processability for the high-potential class of push-pull polymers, generally requiring high boiling solvents, are made accessible. With our method we demonstrate excellent control over the blend stoichiometry and efficient mixing. Furthermore, we provide visualization of the nano morphology of the different NPs to obtain structural information down to similar to 2 nm resolution using advanced analytical electron microscopy. The imaging directly reveals very small compositional demixing in the PCDTBT:PC71BM blend NPs, in the size range of about <5 nm, indicating fine mixing at the molecular level. The suitability of the proposed methodology and materials towards the aspects of eco-friendly processing of organic solar cells is demonstrated through a processing of lab scale NPs solar cell prototypes reaching a power conversion efficiency of 1.9%. (C) 2016 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000388053600021 Publication Date 2016-09-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0927-0248 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.784 Times cited 32 Open Access OpenAccess  
  Notes ; This work was supported by BOF funding of Hasselt University, the Interreg project Organext, and the IAP 7/05 project FS2 (Functional Supramolecular Systems), granted by the Science Policy Office of the Belgian Federal Government (BELSPO). A.E. is a post-doctoral fellow of the Flanders Research Foundation (FWO). M.P. gratefully acknowledges the SIM NanoForce program for financial support. S.B. further acknowledges financial support from the European Research Council (ERC Starting Grant #335078-COLOURATOMS). The authors are thankful for technical support by J. Smits, T. Vangerven, and J. Baccus. ; ecas_sara Approved Most recent IF: 4.784  
  Call Number UA @ lucian @ c:irua:139157UA @ admin @ c:irua:139157 Serial 4450  
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