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Author Hofer, C.; Gao, C.; Chennit, T.; Yuan, B.; Pennycook, T.J. pdf  url
doi  openurl
  Title Phase offset method of ptychographic contrast reversal correction Type A1 Journal Article
  Year 2024 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume Issue Pages (down) 113922  
  Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date 2024-01-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record  
  Impact Factor 2.2 Times cited Open Access  
  Notes FWO, G013122N ; Horizon 2020 Framework Programme; European Research Council, 802123-HDEM ; European Research Council; Approved Most recent IF: 2.2; 2024 IF: 2.843  
  Call Number EMAT @ emat @c:irua:202379 Serial 8988  
Permanent link to this record
 

 
Author Dobrynin, A.N.; Temst, K.; Lievens, P.; Margueritat, J.; Gonzalo, J.; Afonso, C.N.; Piscopiello, E.; Van Tendeloo, G. doi  openurl
  Title Observation of Co/CoO nanoparticles below the critical size for exchange bias Type A1 Journal article
  Year 2007 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 101 Issue 11 Pages (down) 113913-113917  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract We compare the magnetic properties of pure and oxidized Co nanoparticles embedded in an amorphous Al2O3 matrix. Nanoparticles with diameters of 2 or 3 nm were prepared by alternate pulsed laser deposition in high vacuum conditions, and some of them were exposed to O-2 after production and before being embedded. The nanoparticles are organized in layers, the effective edge-to-edge in-depth separation being 5 or 10 nm. The lower saturation magnetizations per Co atom for the samples containing oxidized nanoparticles provide evidence for the formation of antiferromagnetic CoO shells in the nanoparticles. None of the samples with Co/CoO nanoparticles show exchange bias, while vertical hysteresis loop shifts and enhanced coercivities (as compared to samples with pure Co nanoparticles) are observed. This constitutes evidence for the nanoparticles size being in all cases smaller than the critical size for exchange bias. The difference in coercivity versus temperature dependences for the samples with pure and oxidized Co nanoparticles shows that the exchange anisotropy in Co/CoO nanoparticles appears at temperatures lower than 50 K. (c) 2007 American Institute of Physics.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000247306000098 Publication Date 2007-06-12  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 27 Open Access  
  Notes Approved Most recent IF: 2.068; 2007 IF: 2.171  
  Call Number UA @ lucian @ c:irua:103596 Serial 2415  
Permanent link to this record
 

 
Author Papp, G.; Borza, S.; Peeters, F.M. doi  openurl
  Title Spin transport in a Mn-doped ZnSe asymmetric tunnel structure Type A1 Journal article
  Year 2005 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 97 Issue 11 Pages (down) 113901-113905  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Spin-dependent tunneling of electrons in a diluted magnetic semiconductor ZnSe/Zn1-xMnxSe/Zn1-yMnySe/ZnSe/Zn1-xMnxSe/ZnSe heterostructure is investigated theoretically in the presence of parallel magnetic and electric fields, but our modeling is appropriate for any dilute magnetic II-VI semiconductor system. In the studied asymmetric system the transmission of electrons and the degree of spin polarization depend on the strength of the magnetic and electric fields and on the direction of the applied bias. For suitable magnetic fields, the output current of the system exhibits a nearly 100% spin polarization and the device can be used as a spin filter. (C) 2005 American Institute of Physics.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000229804700072 Publication Date 2005-05-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 26 Open Access  
  Notes Approved Most recent IF: 2.068; 2005 IF: 2.498  
  Call Number UA @ lucian @ c:irua:102728 Serial 3102  
Permanent link to this record
 

 
Author Gao, C.; Hofer, C.; Pennycook, T.J. url  doi
openurl 
  Title On central focusing for contrast optimization in direct electron ptychography of thick samples Type A1 Journal article
  Year 2024 Publication Ultramicroscopy Abbreviated Journal  
  Volume 256 Issue Pages (down) 113879-7  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the projected potential becomes strong for both direct and iterative inversion ptychography methods. It has recently been shown that these reversals can often be counteracted in direct ptychography methods by adapting the focus. Here we provide an explanation of why the best contrast is often found with the probe focused to the middle of the sample. The phase contribution due to defocus at each sample slice above and below the central plane in this configuration effectively cancels out, which can prevent contrast reversals when dynamical scattering effects are not overly strong. In addition we show that the convergence angle can be an important consideration for removal of contrast reversals in relatively thin samples.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001112166400001 Publication Date 2023-11-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:202029 Serial 9066  
Permanent link to this record
 

 
Author Şentürk, DG.; Yu, CP.; De Backer, A.; Van Aert, S. pdf  url
doi  openurl
  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 (down) 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 Bafekry, A. doi  openurl
  Title Graphene-like BC₆N single-layer: tunable electronic and magnetic properties via thickness, gating, topological defects, and adatom/molecule Type A1 Journal article
  Year 2020 Publication Physica E-Low-Dimensional Systems & Nanostructures Abbreviated Journal Physica E  
  Volume 118 Issue Pages (down) 113850-15  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract By using density functional theory-based first-principles calculations, we investigate the structural, electronic, optical, and transport properties of pristine single-layer BC6N. Under different external actions and functionalization. Increasing the thickness of the structure results in a decrease of the band gap. Applying a perpendicular electric field decreases the band gap and a semiconductor-to-topological insulator transition is revealed. Uniaxial and biaxial strains of +8% result in a semiconductor-to-metal transition. Nanoribbons of BC6N having zigzag edge with even (odd) values of widths, become metal (semiconductor), while the armchair edge nanoribbons exhibit robust semiconducting behavior. In addition, we systematically investigate the effect of surface adatom and molecule, substitutional impurity and defect engineering on the electronic properties of single-layer BC6N and found transitions from metal to half-metal, to ferromagnetic metal, to dilute magnetic semiconductor, and even to spin-glass semiconductor. Furthermore we found that, topological defects including vacancies and Stone–Wales type, induce magnetism in single-layer BC6N.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000515321700032 Publication Date 2019-12-04  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1386-9477 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.3 Times cited 30 Open Access  
  Notes ; ; Approved Most recent IF: 3.3; 2020 IF: 2.221  
  Call Number UA @ admin @ c:irua:169750 Serial 6530  
Permanent link to this record
 

 
Author Van den Broek, W.; Jannis, D.; Verbeeck, J. pdf  url
doi  openurl
  Title Convexity constraints on linear background models for electron energy-loss spectra Type A1 Journal Article
  Year 2023 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 254 Issue Pages (down) 113830  
  Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;  
  Abstract In this paper convexity constraints are derived for a background model of electron energy loss spectra (EELS) that is linear in the fitting parameters. The model outperforms a power-law both on experimental and simulated backgrounds, especially for wide energy ranges, and thus improves elemental quantification results. Owing to the model’s linearity, the constraints can be imposed through fitting by quadratic programming. This has important advantages over conventional nonlinear power-law fitting such as high speed and a guaranteed unique solution without need for initial parameters. As such, the need for user input is significantly reduced, which is essential for unsupervised treatment of large datasets. This is demonstrated on a demanding spectrum image of a semiconductor device sample with a high number of elements over a wide energy range.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date 2023-08-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record  
  Impact Factor 2.2 Times cited Open Access Not_Open_Access  
  Notes ECSEL, 875999 ; Horizon 2020; Horizon 2020 Framework Programme; Electronic Components and Systems for European Leadership; Approved Most recent IF: 2.2; 2023 IF: 2.843  
  Call Number EMAT @ emat @c:irua:200588 Serial 8961  
Permanent link to this record
 

 
Author Hofer, C.; Pennycook, T.J. pdf  url
doi  openurl
  Title Reliable phase quantification in focused probe electron ptychography of thin materials Type A1 Journal Article
  Year 2023 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 254 Issue Pages (down) 113829  
  Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;  
  Abstract Electron ptychography provides highly sensitive, dose efficient phase images which can be corrected for aberrations after the data has been acquired. This is crucial when very precise quantification is required, such as with sensitivity to charge transfer due to bonding. Drift can now be essentially eliminated as a major impediment to focused probe ptychography, which benefits from the availability of easily interpretable simultaneous Z-contrast imaging. However challenges have remained when quantifying the ptychographic phases of atomic sites. The phase response of a single atom has a negative halo which can cause atoms to reduce in phase when brought closer together. When unaccounted for, as in integrating methods of quantification, this effect can completely obscure the effects of charge transfer. Here we provide a new method of quantification that overcomes this challenge, at least for 2D materials, and is robust to experimental parameters such as noise, sample tilt.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001071608700001 Publication Date 2023-08-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.2 Times cited Open Access  
  Notes FWO, G013122N ; Horizon 2020 Framework Programme; Horizon 2020; European Research Council, 802123-HDEM ; European Research Council; Approved Most recent IF: 2.2; 2023 IF: 2.843  
  Call Number EMAT @ emat @c:irua:200272 Serial 8987  
Permanent link to this record
 

 
Author Denisov, N.; Jannis, D.; Orekhov, A.; Müller-Caspary, K.; Verbeeck, J. pdf  url
doi  openurl
  Title Characterization of a Timepix detector for use in SEM acceleration voltage range Type A1 Journal Article
  Year 2023 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 253 Issue Pages (down) 113777  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Hybrid pixel direct electron detectors are gaining popularity in electron microscopy due to their excellent properties. Some commercial cameras based on this technology are relatively affordable which makes them attractive tools for experimentation especially in combination with an SEM setup. To support this, a detector characterization (Modulation Transfer Function, Detective Quantum Efficiency) of an Advacam Minipix and Advacam Advapix detector in the 15–30 keV range was made. In the current work we present images of Point Spread Function, plots of MTF/DQE curves and values of DQE(0) for these detectors. At low beam currents, the silicon detector layer behaviour should be dominant, which could make these findings transferable to any other available detector based on either Medipix2, Timepix or Timepix3 provided the same detector layer is used.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001026912700001 Publication Date 2023-06-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 2.2 Times cited Open Access OpenAccess  
  Notes The authors acknowledge the financial support of the Research Foundation Flanders (FWO, Belgium) project SBO S000121N. The authors are grateful to Dr. Lobato for productive discussion of methods. Approved Most recent IF: 2.2; 2023 IF: 2.843  
  Call Number EMAT @ emat @c:irua:198258 Serial 8815  
Permanent link to this record
 

 
Author Lobato, I.; De Backer, A.; Van Aert, S. pdf  url
doi  openurl
  Title Real-time simulations of ADF STEM probe position-integrated scattering cross-sections for single element fcc crystals in zone axis orientation using a densely connected neural network Type A1 Journal Article
  Year 2023 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 251 Issue Pages (down) 113769  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Quantification of annular dark field (ADF) scanning transmission electron microscopy (STEM) images in terms

of composition or thickness often relies on probe-position integrated scattering cross sections (PPISCS). In

order to compare experimental PPISCS with theoretically predicted ones, expensive simulations are needed for

a given specimen, zone axis orientation, and a variety of microscope settings. The computation time of such

simulations can be in the order of hours using a single GPU card. ADF STEM simulations can be efficiently

parallelized using multiple GPUs, as the calculation of each pixel is independent of other pixels. However, most

research groups do not have the necessary hardware, and, in the best-case scenario, the simulation time will

only be reduced proportionally to the number of GPUs used. In this manuscript, we use a learning approach and

present a densely connected neural network that is able to perform real-time ADF STEM PPISCS predictions as

a function of atomic column thickness for most common face-centered cubic (fcc) crystals (i.e., Al, Cu, Pd, Ag,

Pt, Au and Pb) along [100] and [111] zone axis orientations, root-mean-square displacements, and microscope

parameters. The proposed architecture is parameter efficient and yields accurate predictions for the PPISCS

values for a wide range of input parameters that are commonly used for aberration-corrected transmission

electron microscopes.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001011617200001 Publication Date 2023-06-01  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 2.2 Times cited Open Access 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 and G0A7723N) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF), Belgium. Approved Most recent IF: 2.2; 2023 IF: 2.843  
  Call Number EMAT @ emat @c:irua:197275 Serial 8812  
Permanent link to this record
 

 
Author Papp, G.; Peeters, F.M. url  doi
openurl 
  Title Resistance maps for a submicron Hall electrosensor in the diffusive regime Type A1 Journal article
  Year 2007 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 101 Issue 11 Pages (down) 113717,1-6  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000247306000084 Publication Date 2007-06-16  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 7 Open Access  
  Notes Approved Most recent IF: 2.068; 2007 IF: 2.171  
  Call Number UA @ lucian @ c:irua:69645 Serial 2879  
Permanent link to this record
 

 
Author Hezareh, T.; Razavi, F.S.; Kremer, R.K.; Habermeier, H.-U.; Lebedev, O.I.; Kirilenko, D.; Van Tendeloo, G. pdf  doi
openurl 
  Title Effect of PbZr0.52Ti0.48O3 thin layer on structure, electronic and magnetic properties of La0.65Sr0.35MnO3 and La0.65Ca0.30MnO3 thin-films Type A1 Journal article
  Year 2011 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 109 Issue 11 Pages (down) 113707,1-113707,8  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Epitaxial thin film heterostructures of high dielectric PbZr<sub>1-x</sub>Ti<sub>x</sub>O<sub>3</sub> (PZT) and La<sub>1-x</sub>A<sub>x</sub>MnO<sub>3</sub> (A-divalent alkaline earth metals such as Sr (LSMO) and Ca (LCMO)) were grown on SrTiO<sub>3</sub> substrates and their structure, temperature dependence of electrical resistivity, and magnetization were investigated as a function of the thickness of the LSMO(LCMO) layer. The microstructures of the samples were analyzed by TEM. By applying an electric field across the PZT layer, we applied a ferrodistortive pressure on the manganite layer and studied the correlations between lattice distortion and electric transport and magnetic properties of the CMR materials.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000292214700069 Publication Date 2011-06-06  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 4 Open Access  
  Notes Approved Most recent IF: 2.068; 2011 IF: 2.168  
  Call Number UA @ lucian @ c:irua:90964 Serial 843  
Permanent link to this record
 

 
Author Milovanovic, S.P.; Masir, M.R.; Peeters, F.M. pdf  doi
openurl 
  Title Bilayer graphene Hall bar with a pn-junction Type A1 Journal article
  Year 2013 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 114 Issue 11 Pages (down) 113706  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract We investigate the magnetic field dependence of the Hall and the bend resistances for a ballistic Hall bar structure containing a pn-junction sculptured from a bilayer of graphene. The electric response is obtained using the billiard model, and we investigate the cases of bilayer graphene with and without a band gap. Two different conduction regimes are possible: (i) both sides of the junction have the same carrier type and (ii) one side of the junction is n-type while the other one is p-type. The first case shows Hall plateau-like features in the Hall resistance that fade away as the band gap opens. The second case exhibits a bend resistance that is asymmetric in magnetic field as a consequence of snake states along the pn-interface, where the maximum is shifted away from zero magnetic field.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000324827200031 Publication Date 2013-09-17  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 3 Open Access  
  Notes This work was supported by the Flemish Science Foundation (FWO-Vl), the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN, and the Methusalem Foundation of the Flemish government. Approved Most recent IF: 2.068; 2013 IF: 2.185  
  Call Number UA @ lucian @ c:irua:111169 Serial 234  
Permanent link to this record
 

 
Author De Backer, A.; Bals, S.; Van Aert, S. pdf  url
doi  openurl
  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 (down) 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 Zhang, Z.; Lobato, I.; De Backer, A.; Van Aert, S.; Nellist, P. pdf  url
doi  openurl
  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 (down) 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 Thiruvottriyur Shanmugam, S.; Trashin, S.; De Wael, K. pdf  url
doi  openurl
  Title Singlet oxygen-based photoelectrochemical detection of DNA Type A1 Journal article
  Year 2022 Publication Biosensors and bioelectronics Abbreviated Journal  
  Volume 195 Issue Pages (down) 113652  
  Keywords A1 Journal article; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)  
  Abstract The current work, designed for the photoelectrochemical detection of DNA, evaluates light-responsive DNA probes carrying molecular photosensitizers generating singlet oxygen (1O2). We take advantage of their chromophore’s ability to produce 1O2 upon photoexcitation and subsequent photocurrent response. Type I, fluorescent and type II photosensitizers were studied using diode lasers at 406 nm blue, 532 nm green and 659 nm red lasers in the presensce and absence of a redox reporter, hydroquinone (HQ). Only type II photosensitizers (producing 1O2) resulted in a noticeable photocurrent in 1–4 nA range upon illumination, in particular, dissolved DNA probes labeled with chlorin e6 and erythrosine were found to give a well-detectable photocurrent response in the presence of HQ. Whereas, Type I photosensitizers and fluorescent chromophores generate negligible photocurrents (<0.15 nA). The analytical performance of the sensing system was evaluated using a magnetic beads-based DNA assay on disposable electrode platforms, with a focus to enhance the sensitivity and robustness of the technique in detecting complementary DNA targets. Amplified photocurrent responses in the range of 70–100 nA were obtained and detection limits of 17 pM and 10 pM were achieved using magnetic beads-captured chlorin e6 and erythrosine labeled DNA probes respectively. The presented novel photoelectrochemical detection can further be optimized and employed in applications for which enzymatic amplification such as polymerase chain reaction (PCR) is not applicable owing to their limitations and as an effective alternative to colorimetric detection when rapid detection of specific nucleic acid targets is required.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000705223300003 Publication Date 2021-09-23  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0956-5663 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access OpenAccess  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:181796 Serial 8930  
Permanent link to this record
 

 
Author Sentürk, D.G.; De Backer, A.; Friedrich, T.; Van Aert, S. pdf  url
doi  openurl
  Title Optimal experiment design for element specific atom counting using multiple annular dark field scanning transmission electron microscopy detectors Type A1 Journal article
  Year 2022 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 242 Issue Pages (down) 113626  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract This paper investigates the possible benefits for counting atoms of different chemical nature when analysing multiple 2D scanning transmission electron microscopy (STEM) images resulting from independent annular dark field (ADF) detector regimes. To reach this goal, the principles of statistical detection theory are used to quantify the probability of error when determining the number of atoms in atomic columns consisting of multiple types of elements. In order to apply this theory, atom-counting is formulated as a statistical hypothesis test, where each hypothesis corresponds to a specific number of atoms of each atom type in an atomic column. The probability of error, which is limited by the unavoidable presence of electron counting noise, can then be computed from scattering-cross sections extracted from multiple ADF STEM images. Minimisation of the probability of error as a function of the inner and outer angles of a specified number of independent ADF collection regimes results in optimal experimental designs. Based on simulations of spherical Au@Ag and Au@Pt core–shell nanoparticles, we investigate how the combination of two non-overlapping detector regimes helps to improve the probability of error when unscrambling two types of atoms. In particular, the combination of a narrow low angle ADF detector with a detector formed by the remaining annular collection regime is found to be optimal. The benefit is more significant if the atomic number Z difference becomes larger. In

addition, we show the benefit of subdividing the detector regime into three collection areas for heterogeneous nanostructures based on a structure consisting of three types of elements, e.g., a mixture of Au, Ag and Al atoms. Finally, these results are compared with the probability of error resulting when one would ultimately use a pixelated 4D STEM detector and how this could help to further reduce the incident electron dose.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000873778100001 Publication Date 0000-00-00  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.2 Times cited Open Access OpenAccess  
  Notes This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert and Grant 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0346.21N and EOS 30489208) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF).; esteem3reported; esteem3jra Approved Most recent IF: 2.2  
  Call Number EMAT @ emat @c:irua:190925 Serial 7118  
Permanent link to this record
 

 
Author de Sousa, A.A.; Chaves, A.; Pereira, T.A.S.; de Farias, G.A.; Peeters, F.M. pdf  doi
openurl 
  Title Wave packet propagation through branched quantum rings under applied magnetic fields Type A1 Journal article
  Year 2019 Publication Physica. E: Low-dimensional systems and nanostructures Abbreviated Journal Physica E  
  Volume 114 Issue 114 Pages (down) 113598  
  Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)  
  Abstract We investigate the effect of opening and closing pathways on the dynamics of electron wave packets in semiconductor quantum rings with different geometries. Our analysis is based on the time evolution of an electron wave packet, within the effective-mass approximation. We demonstrate that opening an extra channel in the quantum ring does not necessarily improve the electron transmission and, depending on the extra channel width, may even reduce it, either due to enhancement of quantum scattering or due to interference. In the latter case, transmission reduction can be controlled through the Aharonov-Bohm phase of the wave function, via an applied magnetic field. It is also shown that, closing one of the channels of the quantum ring, system improves the transmission probability under specific conditions, an effect which is a quantum analog of the Braess paradox.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000482637000039 Publication Date 2019-06-13  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1386-9477 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.221 Times cited Open Access  
  Notes ; This work was financially supported by PRONEX/CNPq/FUNCAP, Science Without Boards (Ciencias Sem Fronteiras) and the bilateral project CNPq-FWO. A. A. Sousa was financially supported by CAPES, under the PDSE contract BEX 7177/ 13-5. T. A. S. Pereira was financially supported by PRONEX/CNPq/FAPEMAT 850109/ 2009 and by CAPES under process BEX 3299/13-9. ; Approved Most recent IF: 2.221  
  Call Number UA @ admin @ c:irua:162777 Serial 5432  
Permanent link to this record
 

 
Author Jannis, D.; Velazco, A.; Béché, A.; Verbeeck, J. url  doi
openurl 
  Title Reducing electron beam damage through alternative STEM scanning strategies, Part II: Attempt towards an empirical model describing the damage process Type A1 Journal article
  Year 2022 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume Issue Pages (down) 113568  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract In this second part of a series we attempt to construct an empirical model that can mimick all experimental observations made regarding the role of an alternative interleaved scan pattern in STEM imaging on the beam damage in a specific zeolite sample. We make use of a 2D diffusion model that describes the dissipation of the deposited beam energy in the sequence of probe positions that are visited during the scan pattern. The diffusion process allows for the concept of trying to ‘outrun’ the beam damage by carefully tuning the dwell time and distance between consecutively visited probe positions. We add a non linear function to include a threshold effect and evaluate the accumulated damage in each part of the image as a function of scan pattern details. Together, these ingredients are able to describe qualitatively all aspects of the experimental data and provide us with a model that could guide a further optimisation towards even lower beam damage without lowering the applied electron dose. We deliberately remain vague on what is diffusing here which avoids introducing too many sample specific details. This provides hope that the model can be applied also in sample classes that were not yet studied in such great detail by adjusting higher level parameters: a sample dependent diffusion constant and damage threshold.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000832788000003 Publication Date 0000-00-00  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.2 Times cited 4 Open Access OpenAccess  
  Notes D.J., A.V, A.B. and J.V. acknowledge funding from FWO project G093417N (’Compressed sensing enabling low dose imaging in transmission electron microscopy’) and G042920N (’Coincident event detection for advanced spectroscopy in transmission electron microscopy’). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 823717 ESTEEM3. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. J.V. acknowledges funding from GOA project “Solarpaint” of the University of Antwerp .; esteem3reported; esteem3jra; Approved Most recent IF: 2.2  
  Call Number EMAT @ emat @c:irua:188535 Serial 7071  
Permanent link to this record
 

 
Author Chen, Y.Y.; Pourtois, G.; Adelmann, C.; Goux, L.; Govoreanu, B.; Degreave, R.; Jurczak, M.; Kittl, J.A.; Groeseneken, G.; Wouters, D.J. doi  openurl
  Title Insights into Ni-filament formation in unipolar-switching Ni/HfO2/TiN resistive random access memory device Type A1 Journal article
  Year 2012 Publication Applied physics letters Abbreviated Journal Appl Phys Lett  
  Volume 100 Issue 11 Pages (down) 113513-113513,4  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract In this letter, CMOS-compatible Ni/HfO2/TiN resistive random access memory stacks demonstrated attractive unipolar switching properties, showing >10(3) endurance and long retention at 150 degrees C. The Ni bottom electrode (BE) improved the switching yield over the NiSiPt BE. To better understand the unipolar forming mechanism, ab initio simulation and time of flight-secondary ion mass spectroscopy were utilized. Compared to the NiSiPt BE, Ni BE gives larger Ni diffusion in the HfO2 and lower formation enthalpy of Ni2+ species during electrical forming. Both the electrical and physical results supported a Ni-injection mechanism for the filament formation. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3695078]  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000302204900091 Publication Date 2012-03-17  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.411 Times cited 29 Open Access  
  Notes Approved Most recent IF: 3.411; 2012 IF: 3.794  
  Call Number UA @ lucian @ c:irua:98295 Serial 1674  
Permanent link to this record
 

 
Author Zhang, Y.-R.; Xu, X.; Zhao, S.-X.; Bogaerts, A.; Wang, Y.-N. pdf  doi
openurl 
  Title Comparison of electrostatic and electromagnetic simulations for very high frequency plasmas Type A1 Journal article
  Year 2010 Publication Physics of plasmas Abbreviated Journal Phys Plasmas  
  Volume 17 Issue 11 Pages (down) 113512-113512,11  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract A two-dimensional self-consistent fluid model combined with the full set of Maxwell equations is developed to investigate an argon capacitively coupled plasma, focusing on the electromagnetic effects on the discharge characteristics at various discharge conditions. The results indicate that there exist distinct differences in plasma characteristics calculated with the so-called electrostatic model (i.e., without taking into account the electromagnetic effects) and the electromagnetic model (which includes the electromagnetic effects), especially at very high frequencies. Indeed, when the excitation source is in the high frequency regime and the electromagnetic effects are taken into account, the plasma density increases significantly and meanwhile the ionization rate evolves to a very different distribution when the electromagnetic effects are dominant. Furthermore, the dependence of the plasma characteristics on the voltage and pressure is also investigated, at constant frequency. It is observed that when the voltage is low, the difference between these two models becomes more obvious than at higher voltages. As the pressure increases, the plasma density profiles obtained from the electromagnetic model smoothly shift from edge-peaked over uniform to a broad maximum in the center. In addition, the edge effect becomes less pronounced with increasing frequency and pressure, and the skin effect rather than the standing-wave effect becomes dominant when the voltage is high.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Woodbury, N.Y. Editor  
  Language Wos 000285486500105 Publication Date 2010-11-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1070-664X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.115 Times cited 30 Open Access  
  Notes Approved Most recent IF: 2.115; 2010 IF: 2.320  
  Call Number UA @ lucian @ c:irua:84763 Serial 429  
Permanent link to this record
 

 
Author Xiaoyan, S.; Zhang, Y.-R.; Wang, Y.-N.; He, J.-X. doi  openurl
  Title Fluid simulation of the superimposed dual-frequency source effect in inductively coupled discharges Type A1 Journal article
  Year 2021 Publication Physics Of Plasmas Abbreviated Journal Phys Plasmas  
  Volume 28 Issue 11 Pages (down) 113504-113510  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Superimposition of dual frequencies (DFs) is one of the methods used for controlling plasma distribution in an inductively coupled plasma (ICP) source. The effects of a superimposed DF on the argon plasma characteristics have been investigated using a two-dimensional self-consistent fluid model. When both currents are fixed at 6A, the plasma density drops with decrease in one of the source frequencies due to less efficient heating and the plasma uniformity improves significantly. Moreover, for ICP operated with superimposed DFs (i.e., 4.52MHz/13.56MHz and 2.26MHz/13.56MHz), the current source exhibits the same period as the low frequency (LF) component, and the plasma density is higher than that obtained at a single frequency (i.e., 4.52 and 2.26MHz) with the same total current of 12A. However, at superimposed current frequencies of 6.78MHz/13.56MHz, the plasma density is lower than that obtained at a single frequency of 6.78MHz due to the weaker negative azimuthal electric field between two positive maxima during one period of 6.78MHz. When the superimposed DF ICP operates at 2.26 and 13.56MHz, the rapid oscillations of the induced electric field become weaker during one period of 2.26MHz as the current ratio of 2.26MHz/13.56MHz rises from 24A/7 A to 30A/1 A, and the plasma density drops with the current ratio due to weakened electron heating. The uniformity of plasma increases due to sufficient diffusion under the low-density condition.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000760326100004 Publication Date 2021-11-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1070-664x ISBN Additional Links UA library record; WoS full record  
  Impact Factor 2.115 Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: 2.115  
  Call Number UA @ admin @ c:irua:187245 Serial 7974  
Permanent link to this record
 

 
Author Schweigert, I.V.; Schweigert, V.A.; Peeters, F.M. doi  openurl
  Title Perturbation of collisional plasma flow around a charged dust particle: kinetic analysis Type A1 Journal article
  Year 2005 Publication Physics of plasmas Abbreviated Journal Phys Plasmas  
  Volume 12 Issue 11 Pages (down) 113501,1-9  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Woodbury, N.Y. Editor  
  Language Wos 000233569600046 Publication Date 2005-11-07  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1070-664X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.115 Times cited 15 Open Access  
  Notes Approved Most recent IF: 2.115; 2005 IF: 2.182  
  Call Number UA @ lucian @ c:irua:56048 Serial 2575  
Permanent link to this record
 

 
Author Van Winckel, T.; Cools, J.; Vlaeminck, S.E.; Joos, P.; Van Meenen, E.; Borregán-Ochando, E.; Van Den Steen, K.; Geerts, R.; Vandermoere, F.; Blust, R. pdf  url
doi  openurl
  Title Towards harmonization of water quality management : a comparison of chemical drinking water and surface water quality standards around the globe Type A1 Journal article
  Year 2021 Publication Journal Of Environmental Management Abbreviated Journal J Environ Manage  
  Volume 298 Issue Pages (down) 113447-12  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Centre for Research on Environmental and Social Change  
  Abstract Water quality standards (WQS) set the legal definition for safe and desirable water. WQS impose regulatory concentration limits to act as a jurisdiction-specific legislative risk-management tool. Despite its importance in shaping a universal definition of safe, clean water, little information exists with respect to (dis)similarity of chemical WQS worldwide. Therefore, this paper compares chemical WQS for drinking and surface water matrices in eight jurisdictions representing a global geographic distribution: Australia, Brazil, Canada, China, the European Union, the region of Flanders in Belgium, the United States of America, and South Africa. The World Health Organization's list is used as a reference for drinking water standards. Sørensen–Dice indices (SDI) showed little qualitative similarity in the compounds that are regulated in drinking water (median SDI = 40%) and surface water (median SDI = 33%), indicating that the heterogeneity within a matrix is substantial at the level of the standard. Quantitative similarity for matching standards was higher than the qualitative per Kendall correlation (median = 0.73 and 0.58 for drinking water and surface water respectively), yet variance observed within standards remained inexplicably high for organic compounds. Variations in WQS were more pronounced for organic compounds. Most differences cannot be easily explained from a toxicological or risk-based point-of-view. Historical development, ease of measurement, and (toxicological) knowledge gaps on the risk of a vast number of organic compounds are theorized to be the drivers. Therefore, this study argues for a more tailored, risk-based approach in which standards incorporated into water safety plans are dynamically set for compounds that are persistent and could pose a risk for human health and/or aquatic ecosystems. Global variations in WQS should therefore not necessarily be avoided but rather globally harmonized with enough flexibility to ensure a global, up-to-date definition of safe and desirable water everywhere.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000700577400005 Publication Date 2021-08-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0301-4797 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.01 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 4.01  
  Call Number UA @ admin @ c:irua:180765 Serial 8681  
Permanent link to this record
 

 
Author Robert, Hl.; Lobato, I.; Lyu, Fj.; Chen, Q.; Van Aert, S.; Van Dyck, D.; Müller-Caspary, K. url  doi
openurl 
  Title Dynamical diffraction of high-energy electrons investigated by focal series momentum-resolved scanning transmission electron microscopy at atomic resolution Type A1 Journal article
  Year 2022 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 233 Issue Pages (down) 113425  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab  
  Abstract We report a study of scattering dynamics in crystals employing momentum-resolved scanning transmission

electron microscopy under varying illumination conditions. As we perform successive changes of the probe

focus, multiple real-space signals are obtained in dependence of the shape of the incident electron wave.

With support from extensive simulations, each signal is shown to be characterised by an optimum focus for

which the contrast is maximum and which differs among different signals. For instance, a systematic focus

mismatch is found between images formed by high-angle scattering, being sensitive to thickness and chemical

composition, and the first moment in diffraction space, being sensitive to electric fields. It follows that a single

recording at one specific probe focus is usually insufficient to characterise materials comprehensively. Most

importantly, we demonstrate in experiment and simulation that the second moment (
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000734396800009 Publication Date 2021-11-13  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.2 Times cited Open Access OpenAccess  
  Notes We thank Dr. Florian Winkler for valuable discussions and experimental work at the early stages of this study. This work was supported by the Initiative and Network Fund of the Helmholtz Association (Germany) under contracts VH-NG-1317 and ZT-I-0025. This project furthermore received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 770887). Approved Most recent IF: 2.2  
  Call Number EMAT @ emat @c:irua:184833 Serial 6898  
Permanent link to this record
 

 
Author Jannis, D.; Hofer, C.; Gao, C.; Xie, X.; Béché, A.; Pennycook, Tj.; Verbeeck, J. pdf  url
doi  openurl
  Title Event driven 4D STEM acquisition with a Timepix3 detector: Microsecond dwell time and faster scans for high precision and low dose applications Type A1 Journal article
  Year 2022 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 233 Issue Pages (down) 113423  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Four dimensional scanning transmission electron microscopy (4D STEM) records the scattering of electrons in a material in great detail. The benefits offered by 4D STEM are substantial, with the wealth of data it provides facilitating for instance high precision, high electron dose efficiency phase imaging via centre of mass or ptychography based analysis. However the requirement for a 2D image of the scattering to be recorded at each probe position has long placed a severe bottleneck on the speed at which 4D STEM can be performed. Recent advances in camera technology have greatly reduced this bottleneck, with the detection efficiency of direct electron detectors being especially well suited to the technique. However even the fastest frame driven pixelated detectors still significantly limit the scan speed which can be used in 4D STEM, making the resulting data susceptible to drift and hampering its use for low dose beam sensitive applications. Here we report the development of the use of an event driven Timepix3 direct electron camera that allows us to overcome this bottleneck and achieve 4D STEM dwell times down to 100 ns; orders of magnitude faster than what has been possible with frame based readout. We characterize the detector for different acceleration voltages and show that the method is especially well suited for low dose imaging and promises rich datasets without compromising dwell time when compared to conventional STEM imaging.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000734396800003 Publication Date 2021-11-13  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.2 Times cited 31 Open Access OpenAccess  
  Notes This project has received funding from the Euro- pean Union’s Horizon 2020 Research Infrastructure – Integrating Activities for Advanced Communities under grant agreement No 823717 – ESTEEM3. J.V. and A.B. acknowledge funding from FWO project G093417N (‘Compressed sensing enabling low dose imaging in transmission electron microscopy’). J.V. and D.J. ac- knowledge funding from FWO project G042920N ‘Co- incident event detection for advanced spectroscopy in transmission electron microscopy’. We acknowledge funding under the European Union’s Horizon 2020 re- search and innovation programme (J.V. and D.J un- der grant agreement No 101017720, FET-Proactive EBEAM, and C.H., C.G., X.X. and T.J.P. from the Eu- ropean Research Council (ERC) Grant agreement No. 802123-HDEM).; esteem3JRA; esteem3reported Approved Most recent IF: 2.2  
  Call Number EMAT @ emat @c:irua:183948 Serial 6828  
Permanent link to this record
 

 
Author Peelaers, H.; Partoens, B.; Peeters, F.M. url  doi
openurl 
  Title Electronic and dynamical properties of Si/Ge core-shell nanowires Type A1 Journal article
  Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B  
  Volume 82 Issue 11 Pages (down) 113411-113411,4  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Full ab initio techniques are applied to study the electronic and dynamical properties of free standing, hydrogen-passivated Si/Ge core-shell nanowires oriented along the [110] direction. All studied wires exhibit a direct band gap and are found to be structurally stable. The different contributions of the core and shell atoms to the phonon spectra are identified. The acoustic phonon velocities and the frequencies of some typical optical modes are compared with those of pure Si and Ge nanowires. These depend either on the concentration or on the type of core material. Optical modes are hardened and longitudinal acoustic velocities are softened with decreasing wire diameter.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000282270000001 Publication Date 2010-09-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 13 Open Access  
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and NOI-BOF (University of Antwerp). ; Approved Most recent IF: 3.836; 2010 IF: 3.774  
  Call Number UA @ lucian @ c:irua:85421 Serial 995  
Permanent link to this record
 

 
Author Velazco, A.; Béché, A.; Jannis, D.; Verbeeck, J. url  doi
openurl 
  Title Reducing electron beam damage through alternative STEM scanning strategies, Part I: Experimental findings Type A1 Journal article
  Year 2022 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume 232 Issue Pages (down) 113398  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The highly energetic electrons in a transmission electron microscope (TEM) can alter or even completely destroy the structure of samples before sufficient information can be obtained. This is especially problematic in the case of zeolites, organic and biological materials. As this effect depends on both the electron beam and the sample and can involve multiple damage pathways, its study remained difficult and is plagued with irreproducibility issues, circumstantial evidence, rumors, and a general lack of solid data. Here we take on the experimental challenge to investigate the role of the STEM scan pattern on the damage behavior of a commercially available zeolite sample with the clear aim to make our observations as reproducible as possible. We make use of a freely programmable scan engine that gives full control over the tempospatial distribution of the electron probe on the sample and we use its flexibility to obtain multiple repeated experiments under identical conditions comparing the difference in beam damage between a conventional raster scan pattern and a newly proposed interleaved scan pattern that provides exactly the same dose and dose rate and visits exactly the same scan points. We observe a significant difference in beam damage for both patterns with up to 11 % reduction in damage (measured from mass loss). These observations demonstrate without doubt that electron dose, dose rate and acceleration voltage are not the only parameters affecting beam damage in (S)TEM experiments and invite the community to rethink beam damage as an unavoidable consequence of applied electron dose.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000714819200002 Publication Date 2021-10-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.2 Times cited 18 Open Access OpenAccess  
  Notes A.V., D.J., A.B. and J.V. acknowledge funding from FWO project G093417N (’Compressed sensing enabling low dose imaging in transmission electron microscopy’) and G042920N (’Coincident event detection for advanced spectroscopy in transmission electron microscopy’). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 823717 ESTEEM3. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. J.V. acknowledges funding from GOA project “Solarpaint” of the University of Antwerp.; JRA; reported Approved Most recent IF: 2.2  
  Call Number EMAT @ emat @c:irua:183282 Serial 6818  
Permanent link to this record
 

 
Author De wael, A.; De Backer, A.; Lobato, I.; Van Aert, S. pdf  url
doi  openurl
  Title Modelling ADF STEM images using elliptical Gaussian peaks and its effects on the quantification of structure parameters in the presence of sample tilt Type A1 Journal article
  Year 2021 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy  
  Volume Issue Pages (down) 113391  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract A small sample tilt away from a main zone axis orientation results in an elongation of the atomic columns in ADF STEM images. An often posed research question is therefore whether the ADF STEM image intensities of tilted nanomaterials should be quantified using a parametric imaging model consisting of elliptical rather than the currently used symmetrical peaks. To this purpose, simulated ADF STEM images corresponding to different amounts of sample tilt are studied using a parametric imaging model that consists of superimposed 2D elliptical Gaussian peaks on the one hand and symmetrical Gaussian peaks on the other hand. We investigate the quantification of structural parameters such as atomic column positions and scattering cross sections using both parametric imaging models. In this manner, we quantitatively study what can be gained from this elliptical model for quantitative ADF STEM, despite the increased parameter space and computational effort. Although a qualitative improvement can be achieved, no significant quantitative improvement in the estimated structure parameters is achieved by the elliptical model as compared to the symmetrical model. The decrease in scattering cross sections with increasing sample tilt is even identical for both types of parametric imaging models. This impedes direct comparison with zone axis image simulations. Nonetheless, we demonstrate how reliable atom-counting can still be achieved in the presence of small sample tilt.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000704334200001 Publication Date 2021-09-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.843 Times cited Open Access OpenAccess  
  Notes This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887 and No. 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through grants to A.D.w. and A.D.B. and projects G.0502.18N, G.0267.18N, and EOS 30489208. S.V.A. acknowledges TOP BOF funding from the University of Antwerp.; esteem3JRA; esteem3reported Approved Most recent IF: 2.843  
  Call Number EMAT @ emat @c:irua:181462 Serial 6810  
Permanent link to this record
 

 
Author Depla, D.; Li, X.Y.; Mahieu, S.; van Aeken, K.; Leroy, W.P.; Haemers, J.; de Gryse, R.; Bogaerts, A. doi  openurl
  Title Rotating cylindrical magnetron sputtering: simulation of the reactive process Type A1 Journal article
  Year 2010 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 107 Issue 11 Pages (down) 113307,1-113307,9  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract A rotating cylindrical magnetron consists of a cylindrical tube, functioning as the cathode, which rotates around a stationary magnet assembly. In stationary mode, the cylindrical magnetron behaves similar to a planar magnetron with respect to the influence of reactive gas addition to the plasma. However, the transition from metallic mode to poisoned mode and vice versa depends on the rotation speed. An existing model has been modified to simulate the influence of target rotation on the well known hysteresis behavior during reactive magnetron sputtering. The model shows that the existing poisoning mechanisms, i.e., chemisorption, direct reactive ion implantation and knock on implantation, are insufficient to describe the poisoning behavior of the rotating target. A better description of the process is only possible by including the deposition of sputtered material on the target.  
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  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000278907100020 Publication Date 2010-06-07  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 15 Open Access  
  Notes Approved Most recent IF: 2.068; 2010 IF: 2.079  
  Call Number UA @ lucian @ c:irua:82631 Serial 2930  
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