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Author (down) Quintelier, M.; Perkisas, T.; Poppe, R.; Batuk, M.; Hendrickx, M.; Hadermann, J.
Title Determination of spinel content in cycled Li1.2Ni0.13Mn0.54Co0.13O2 using three-dimensional electron diffraction and precession electron diffraction Type A1 Journal article
Year 2021 Publication Symmetry-Basel Abbreviated Journal Symmetry-Basel
Volume 13 Issue 11 Pages 1989-17
Keywords A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM); Electron microscopy for materials research (EMAT)
Abstract Among lithium battery cathode materials, Li1.2Ni0.13Mn0.54Co0.13O2 (LR-NMC) has a high theoretical capacity, but suffers from voltage and capacity fade during cycling. This is partially ascribed to transition metal cation migration, which involves the local transformation of the honeycomb layered structure to spinel-like nano-domains. Determination of the honeycomb layered/spinel phase ratio from powder X-ray diffraction data is hindered by the nanoscale of the functional material and the domains, diverse types of twinning, stacking faults, and the possible presence of the rock salt phase. Determining the phase ratio from transmission electron microscopy imaging can only be done for thin regions near the surfaces of the crystals, and the intense beam that is needed for imaging induces the same transformation to spinel as cycling does. In this article, it is demonstrated that the low electron dose sufficient for electron diffraction allows the collection of data without inducing a phase transformation. Using calculated electron diffraction patterns, we demonstrate that it is possible to determine the volume ratio of the different phases in the particles using a pair-wise comparison of the intensities of the reflections. Using this method, the volume ratio of spinel structure to honeycomb layered structure is determined for a submicron sized crystal from experimental three-dimensional electron diffraction (3D ED) and precession electron diffraction (PED) data. Both twinning and the possible presence of the rock salt phase are taken into account. After 150 charge-discharge cycles, 4% of the volume in LR-NMC particles was transformed irreversibly from the honeycomb layered structure to the spinel structure. The proposed method would be applicable to other multi-phase materials as well.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000815310500001 Publication Date 2021-10-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2073-8994 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.457 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 1.457
Call Number UA @ admin @ c:irua:189468 Serial 7080
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Author (down) Quintanilla, M.; Zhang, Y.; Liz-Marzan, L.M.
Title Subtissue plasmonic heating monitored with CaF2:Nd3+,Y3+ nanothermometers in the second biological window Type A1 Journal article
Year 2018 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 30 Issue 8 Pages 2819-2828
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Measuring temperature in biological environments is an ambitious goal toward supporting medical treatment and diagnosis. Minimally invasive techniques based on optical probes require very specific properties that are difficult to combine within a single material. These include high chemical stability in aqueous environments, optical signal stability, low toxicity, high emission intensity, and, essential, working at wavelengths within the biological transparency windows so as to minimize invasiveness while maximizing penetration depth. We propose CaF2:Nd3+,Y3+ as a candidate for thermometry based on an intraband ratiometric approach, fully working within the biological windows (excitation at 808 nm; emission around 1050 nm). We optimized the thermal probes through the addition of Y3+ as a dopant to improve both emission intensity and thermal sensitivity. To define the conditions under which the proposed technique can be applied, gold nanorods were used to optically generate subtissue hot areas, while the resulting temperature variation was monitored with the new nanothermometers.
Address
Corporate Author Thesis
Publisher American Chemical Society Place of Publication Washington, D.C Editor
Language Wos 000431088400038 Publication Date 2018-03-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 28 Open Access Not_Open_Access
Notes ; The authors would like to thank Dr. Guillermo Gonzalez Rubio for the kind support with the synthesis of gold nanorods. M.Q and L.M.L.-M. acknowledge financial support from the European Commission under the Marie Sklodowska-Curie program (H2020-MSCA-IF-2014_659021 – PHELLINI). Y.Z. acknowledges financial support from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 665501 through a FWO [PEGASUS]^2 Marie Sklodowska-Curie fellowship (12U4917N). ; Approved Most recent IF: 9.466
Call Number UA @ lucian @ c:irua:151576 Serial 5042
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Author (down) Quintana, M.; Montellano, A.; Esau del Rio Castillo, A.; Van Tendeloo, G.; Bittencourt, C.; Prato, M.
Title Selective organic functionalization of graphene bulk or graphene edges Type A1 Journal article
Year 2011 Publication Chemical communications Abbreviated Journal Chem Commun
Volume 47 Issue 33 Pages 9330-9332
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Graphene sheets have been functionalized with a PAMAM dendron, finding that graphene can be efficiently functionalized all over the surface, or only at the edges, depending on the reactions used in the functionalization process.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000293648200010 Publication Date 2011-07-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-7345;1364-548X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.319 Times cited 84 Open Access
Notes Approved Most recent IF: 6.319; 2011 IF: 6.169
Call Number UA @ lucian @ c:irua:91892 Serial 2968
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Author (down) Quintana, M.; Ke, X.; Van Tendeloo, G.; Meneghetti, M.; Bittencourt, C.; Prato, M.
Title Light-induced selective deposition of Au nanoparticles on single-wall carbon nanotubes Type A1 Journal article
Year 2010 Publication ACS nano Abbreviated Journal Acs Nano
Volume 4 Issue 10 Pages 6105-6113
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Novel applications of single-walled carbon nanotubes (SWNT) rely on the development of new strategies to make them easier to handle without affecting their structural properties. In this work, we have selectively deposited Au nanoparticles (Au NP) on SWNT assisted by UV light irradiation. XPS analysis and UV-vis spectroscopy indicate that the deposition occurs at the defects generated after oxidation of the SWNT. By addition of n-dodecylthiol, the separation of oxidized tubes with Au NP (Au-ox-SWNT) from tubes devoid of Au NP (bare tubes, b-SWNT) was achieved. Raman and UV-vis-NIR spectra indicate that UV irradiation induces a faster nucleation of Au NP on metallic SWNT. This new technique can be useful for the preparation of nanohybrid composites with enhanced properties, as increased thermal stability, and to obtain purified SWNT.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000283453700081 Publication Date 2010-09-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.942 Times cited 26 Open Access
Notes Approved Most recent IF: 13.942; 2010 IF: 9.865
Call Number UA @ lucian @ c:irua:99202 Serial 1819
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Author (down) Quintana, M.; Grzelczak, M.; Spyrou, K.; Kooi, B.; Bals, S.; Van Tendeloo, G.; Rudolf, P.; Prato, M.
Title Production of large graphene sheets by exfoliation of graphite under high power ultrasound in the presence of tiopronin Type A1 Journal article
Year 2012 Publication Chemical communications Abbreviated Journal Chem Commun
Volume 48 Issue 100 Pages 12159-12161
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Under ultrasonication, the production of high quality graphene layers by exfoliation of graphite was achieved via addition of tiopronin as an antioxidant.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000311411100003 Publication Date 2012-10-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-7345;1364-548X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.319 Times cited 39 Open Access
Notes This work was financially supported by the University of Trieste, INSTM, Italian Ministry of Education MIUR (cofin Prot. 20085M27SS) and by the "Graphene-based electronics'' research program of the Foundation for Fundamental Research on Matter (FOM). Part of this work was supported by funding from the ERC grant No 246791COUNTATOMS. MQ acknowledges the financial support from CONACyT CB-2011-01-166914 and FAI-UASLP. Approved Most recent IF: 6.319; 2012 IF: 6.378
Call Number UA @ lucian @ c:irua:105230 Serial 2724
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Author (down) Quintana, M.; Grzelczak, M.; Spyrou, K.; Calvaresi, M.; Bals, S.; Kooi, B.; Van Tendeloo, G.; Rudolf, P.; Zerbetto, F.; Prato, M.
Title A simple road for the transformation of few-layer graphene into MWNTs Type A1 Journal article
Year 2012 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 134 Issue 32 Pages 13310-13315
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We report the direct formation of multiwalled carbon nanotubes (MWNT) by ultrasonication of graphite in dimethylformamide (DMF) upon addition of ferrocene aldehyde (Fc-CHO). The tubular structures appear exclusively at the edges of graphene layers and contain Fe clusters. Pc in conjunction with benzyl aldehyde, or other Fc derivatives, does not induce formation of NT. Higher amounts of Fc-CHO added to the dispersion do not increase significantly MWNT formation. Increasing the temperature reduces the amount of formation of MWNTs and shows the key role of ultrasound-induced cavitation energy. It is concluded that Fc-CHO first reduces the concentration of radical reactive species that slice graphene into small moieties, localizes itself at the edges of graphene, templates the rolling up of a sheet to form a nanoscroll, where it remains trapped, and finally accepts and donates unpaired electron to the graphene edges and converts the less stable scroll into a MWNT. This new methodology matches the long held notion that CNTs are rolled up graphene layers. The proposed mechanism is general and will lead to control the production of carbon nanostructures by simple ultrasonication treatments.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000307487200034 Publication Date 2012-05-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863;1520-5126; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.858 Times cited 56 Open Access
Notes This work was supported by the University of Trieste, the Italian Ministry of Education MIUR (cofin Prot. 20085M27SS), the European Union through the ERC grant No. 246791 – COUNTATOMS, the grant agreement for an Integrated Infrastructure Initiative N. 262348 ESMI, and the “Graphene-based electronics” research program of the Foundation for Fundamental Research on Matter (FOM). Approved Most recent IF: 13.858; 2012 IF: 10.677
Call Number UA @ lucian @ c:irua:101109 Serial 3003
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Author (down) Queralto, A.; Graf, D.; Frohnhoven, R.; Fischer, T.; Vanrompay, H.; Bals, S.; Bartasyte, A.; Mathur, S.
Title LaFeO3 nanofibers for high detection of sulfur-containing gases Type A1 Journal article
Year 2019 Publication ACS Sustainable Chemistry and Engineering Abbreviated Journal Acs Sustain Chem Eng
Volume 7 Issue 7 Pages 6023-6032
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Lanthanum ferrite nanofibers were electrospun from a chemical sol and calcined at 600 degrees C to obtain singlephase LaFeO3 (LFO) perovskite. High-resolution transmission electron microscopy in conjunction with 3D tomographic analysis confirmed an interwoven network of hollow and porous (surface) LFO nanofibers. Owing to their high surface area and p-type behavior, the nanofiber meshes showed high chemoselectivity toward reducing toxic gases (SO2, H2S) that could be reproducibly detected at very low concentrations (<1 ppm), well below the threshold values for occupational safety and health. An increased sensitivity was observed in the temperature range of 150-300 degrees C with maximum sensor response at 250 degrees C. The surface reaction at the heterogeneous solid (LFO)/gas (SO2) interface that confirmed the formation of La-2(SO4)(3) was investigated by X-ray photoelectron spectroscopy. Moreover, the LFO fibers showed a high selectivity in the detection of oxidizing and reducing gases. Whereas superior detection of NH3 and H2S was measured, little response was observed for CO and NO2. Finally, the integration of nanowire meshes in commercial sensor platforms was successfully demonstrated.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000461978200047 Publication Date 2019-02-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2168-0485 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.951 Times cited 41 Open Access OpenAccess
Notes ; The authors kindly acknowledge the ERA.Net RUS Plus project FONSENS funded by the German Federal Ministry of Education and Research (BMBF) under the grant no. 01DJ16017. A.Q. highly appreciates the support of the Alexander von Humboldt Foundation (grant no. AVH 1184642) and the BMBF for his postdoctoral fellowship. A.Q., D.G., R.F., T.F., and S.M. also kindly acknowledge the financial support of the University of Cologne. H.V. acknowledges financial support by the Research Foundation Flanders (FWO grant 1S32617N). S.B. acknowledges financial support from European Research Council (ERC Starting Grant #335078-COLOURATOMS). We also express our gratitude to Prof. Dr. J. Hadermann from the Electron Microscopy for Materials Science group at the University of Antwerp for her assistance. A.B. is grateful for the EUR EIPHI program (grant no. ANR-17-EURE-0002). ; Approved Most recent IF: 5.951
Call Number UA @ admin @ c:irua:158535 Serial 5263
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Author (down) Quan, L.N.; Ma, D.; Zhao, Y.; Voznyy, O.; Yuan, H.; Bladt, E.; Pan, J.; de Arquer, F.P.G.; Sabatini, R.; Piontkowski, Z.; Emwas, A.-H.; Todorovic, P.; Quintero-Bermudez, R.; Walters, G.; Fan, J.Z.; Liu, M.; Tan, H.; Saidaminov, M., I; Gao, L.; Li, Y.; Anjum, D.H.; Wei, N.; Tang, J.; McCamant, D.W.; Roeffaers, M.B.J.; Bals, S.; Hofkens, J.; Bakr, O.M.; Lu, Z.-H.; Sargent, E.H.
Title Edge stabilization in reduced-dimensional perovskites Type A1 Journal article
Year 2020 Publication Nature Communications Abbreviated Journal Nat Commun
Volume 11 Issue 1 Pages 170
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Reduced-dimensional perovskites are attractive light-emitting materials due to their efficient luminescence, color purity, tunable bandgap, and structural diversity. A major limitation in perovskite light-emitting diodes is their limited operational stability. Here we demonstrate that rapid photodegradation arises from edge-initiated photooxidation, wherein oxidative attack is powered by photogenerated and electrically-injected carriers that diffuse to the nanoplatelet edges and produce superoxide. We report an edge-stabilization strategy wherein phosphine oxides passivate unsaturated lead sites during perovskite crystallization. With this approach, we synthesize reduced-dimensional perovskites that exhibit 97 +/- 3% photoluminescence quantum yields and stabilities that exceed 300 h upon continuous illumination in an air ambient. We achieve green-emitting devices with a peak external quantum efficiency (EQE) of 14% at 1000 cd m(-2); their maximum luminance is 4.5 x 10(4) cd m(-2) (corresponding to an EQE of 5%); and, at 4000 cd m(-2), they achieve an operational half-lifetime of 3.5 h.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000551458200001 Publication Date 2020-01-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-1723 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 16.6 Times cited 147 Open Access OpenAccess
Notes ; This publication is based in part on work supported by an award (KUS-11-009-21) from the King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program, by the Ontario Research Fund (ORF), by the Natural Sciences and Engineering Research Council (NSERC) of Canada, and by the US Department of Navy, Office of Naval Research (Grant Award No. N00014-17-12524). H.Y. acknowledges the Research Foundation-Flanders (FWO Vlaanderen) for a postdoctoral fellowship. E.B. gratefully acknowledges financial support by the Research Foundation-Flanders (FWO Vlaanderen). S.B. acknowledges financial support from European Research Council (ERC Starting Grant #815128-REALNANO). M.B.J.R. and J.H. acknowledge the Research Foundation-Flanders (FWO, Grants G.0962.13, G.0B39.15, AKUL/11/14 and G0H6316N), KU Leuven Research Fund (C14/15/053) and the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ ERC Grant Agreement No. [307523], ERC-Stg LIGHT to M.B.J.R. DFT calculations were performed on the IBM BlueGene Q supercomputer with support from the Southern Ontario Smart Computing Innovation Platform (SOSCIP). M.I.S. acknowledges the Banting Postdoctoral Fellowship program from the Natural Sciences and Engineering Research Council of Canada (NSERC). H.T. acknowledges the Netherlands Organisation for Scientific Research (NWO) for a Rubicon grant (680-50-1511). ; sygma Approved Most recent IF: 16.6; 2020 IF: 12.124
Call Number UA @ admin @ c:irua:171327 Serial 6496
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Author (down) Pullini, D.; Sgroi, M.; Mahmoud, A.; Gauquelin, N.; Maschio, L.; Lorenzo-Ferrari, A.M.; Groenen, R.; Damen, C.; Rijnders, G.; van den Bos, K.H.W.; Van Aert, S.; Verbeeck, J.
Title One step toward a new generation of C-MOS compatible oxide p-n junctions: Structure of the LSMO/ZnO interface elucidated by an experimental and theoretical synergic work Type A1 Journal article
Year 2017 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
Volume 9 Issue 9 Pages 20974-20980
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Heterostructures formed by La0.7Sr0.3MnO3/ZnO (LSMO/ZnO) interfaces exhibit extremely interesting electronic properties making them promising candidates for novel oxide p–n junctions, with multifunctional features. In this work, the structure of the interface is studied through a combined experimental/theoretical approach. Heterostructures were grown epitaxially and homogeneously on 4″ silicon wafers, characterized by advanced electron microscopy imaging and spectroscopy and simulated by ab initio density functional theory calculations. The simulation results suggest that the most stable interface configuration is composed of the (001) face of LSMO, with the LaO planes exposed, in contact with the (112̅0) face of ZnO. The ab initio predictions agree well with experimental high-angle annular dark field scanning transmission electron microscopy images and confirm the validity of the suggested structural model. Electron energy loss spectroscopy confirms the atomic sharpness of the interface. From statistical parameter estimation theory, it has been found that the distances between the interfacial planes are displaced from the respective ones of the bulk material. This can be ascribed to the strain induced by the mismatch between the lattices of the two materials employed
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000404090000079 Publication Date 2017-05-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1944-8244 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.504 Times cited 4 Open Access OpenAccess
Notes Financial support is acknowledged from the European Commission – DG research and innovation to the collaborative research project named Interfacing oxides (IFOX, Contract No. NMP3-LA-2010-246102). N.G. and J.V. acknowledge the European Union (EU) Council under the 7th Framework Program (FP7) ERC Starting Grant 278510 VORTEX for support. S.V.A. and K.H.W.B. acknowledge financial support from the Research Foundation Flanders through project fundings (G.0374.13N , G.0368.15N, and G.0369.15N) and a Ph.D. research grant to K.H.W.B. The microscope was partly funded by the Hercules Fund from the Flemish Government. The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. CINECA is acknowledged for computational facilities (Iscra project HP10CMO1UP). Approved Most recent IF: 7.504
Call Number EMAT @ emat @ c:irua:144431UA @ admin @ c:irua:144431 Serial 4621
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Author (down) Pulinthanathu Sree, S.; Dendooven, J.; Geerts, L.; Ramachandran, R.K.; Javon, E.; Ceyssens, F.; Breynaert, E.; Kirschhock, C.E.A.; Puers, R.; Altantzis, T.; Van Tendeloo, G.; Bals, S.; Detavernier, C.; Martens, J.A.
Title 3D porous nanostructured platinum prepared using atomic layer deposition Type A1 Journal article
Year 2017 Publication Journal of materials chemistry A : materials for energy and sustainability Abbreviated Journal J Mater Chem A
Volume 5 Issue 5 Pages 19007-19016
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract A robust and easy to handle 3D porous platinum structure was created via replicating the 3D channel system

of an ordered mesoporous silica material using atomic layer deposition (ALD) over micrometer distances.

After ALD of Pt in the silica material, the host template was digested using hydrogen fluoride (HF). A fully

connected ordered Pt nanostructure was obtained with morphology and sizes corresponding to that of

the pores of the host matrix, as revealed with high-resolution scanning transmission electron

microscopy and electron tomography. The Pt nanostructure consisted of hexagonal Pt rods originating

from the straight mesopores (11 nm) of the host structure and linking features resulting from Pt

replication of the interconnecting mesopore segments (2–4 nm) present in the silica host structure.

Electron tomography of partial replicas, made by incomplete infilling of Zeotile-4 material with Pt,

provided insight in the connectivity and formation mechanism of the Pt nanostructure by ALD. The Pt

replica was evaluated for its potential use as electrocatalyst for the hydrogen evolution reaction, one of

the half-reactions of water electrolysis, and as microelectrode for biomedical sensing. The Pt replica

showed high activity for the hydrogen evolution reaction and electrochemical characterization revealed

a large impedance improvement in comparison with reference Pt electrodes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000411232100010 Publication Date 2017-06-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2050-7488 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.867 Times cited 9 Open Access OpenAccess
Notes This work was supported by the Flemish government through long-term structural funding (Methusalem) to JAM and FWO for a research project (G0A5417N). JD, TA and FC acknowledge Flemish FWO for a post-doctoral fellowship. S. B. acknowledges funding from ERC Starting Grant COLOURATOMS (335078). (ROMEO:yellow; preprint:; postprint:restricted ; pdfversion:cannot); saraecas; ECAS_Sara; Approved Most recent IF: 8.867
Call Number EMAT @ emat @ c:irua:144624 c:irua:144624 c:irua:144624UA @ admin @ c:irua:144624 Serial 4634
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Author (down) Psilodimitrakopoulos, S.; Orekhov, A.; Mouchliadis, L.; Jannis, D.; Maragkakis, G.M.; Kourmoulakis, G.; Gauquelin, N.; Kioseoglou, G.; Verbeeck, J.; Stratakis, E.
Title Optical versus electron diffraction imaging of Twist-angle in 2D transition metal dichalcogenide bilayers Type A1 Journal article
Year 2021 Publication npj 2D Materials and Applications Abbreviated Journal
Volume 5 Issue 1 Pages 77
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Atomically thin two-dimensional (2D) materials can be vertically stacked with van der Waals bonds, which enable interlayer coupling. In the particular case of transition metal dichalcogenide (TMD) bilayers, the relative direction between the two monolayers, coined as twist-angle, modifies the crystal symmetry and creates a superlattice with exciting properties. Here, we demonstrate an all-optical method for pixel-by-pixel mapping of the twist-angle with a resolution of 0.55(degrees), via polarization-resolved second harmonic generation (P-SHG) microscopy and we compare it with four-dimensional scanning transmission electron microscopy (4D STEM). It is found that the twist-angle imaging of WS2 bilayers, using the P-SHG technique is in excellent agreement with that obtained using electron diffraction. The main advantages of the optical approach are that the characterization is performed on the same substrate that the device is created on and that it is three orders of magnitude faster than the 4D STEM. We envisage that the optical P-SHG imaging could become the gold standard for the quality examination of TMD superlattice-based devices.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000694849200001 Publication Date 2021-09-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2397-7132 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 4 Open Access OpenAccess
Notes This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call European R & T Cooperation-Grant Act of Hellenic Institutions that have successfully participated in Joint Calls for Proposals of European Networks ERA NETS (National project code: GRAPH-EYE T8 Epsilon Rho Alpha 2-00009 and European code: 26632, FLAGERA). L.M., G.Ko. and G.Ki. acknowledge funding by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “First Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant” (Project No: HFRI-FM17-3034). GKi, S.P. and G.M.M. acknowledge funding from a research co-financed by Greece and the European Union (European Social Fund-ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning 2014-2020” in the context of the project “Crystal quality control of two-dimensional materials and their heterostructures via imaging of their non-linear optical properties” (MIS 5050340)“. J.V acknowledges funding from FWO G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund, EU. J.V. and N.G. acknowledge funding from the European Union under the Horizon 2020 programme within a contract for Integrating Activities for Advanced Communities No 823717-ESTEEM3. J.V. N.G. and A.O. acknowledge funding through a GOA project ”Solarpaint" of the University of Antwerp. Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:181610 Serial 6877
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Author (down) Pshirkov, J.S.; Kazakov, S.M.; Abakumov, A.M.; Putilin, S.N.; Antipov, E.V.; Bougerol-Chaillout, C.; Lebedev, O.I.; Van Tendeloo, G.
Title Synthesis and characterization of new phases: Sr3.75K1.75Bi3O12 and Sr3.1Na2.9Bi3O12 Type A1 Journal article
Year 2000 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 152 Issue 2 Pages 492-502
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000088056400025 Publication Date 2002-09-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 2 Open Access
Notes Approved Most recent IF: 2.299; 2000 IF: 1.527
Call Number UA @ lucian @ c:irua:54706 Serial 3414
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Author (down) Prouteau, C.; Verbist, K.; Hamet, J.F.; Mercey, B.; Hervieu, M.; Raveau, B.; Van Tendeloo, G.
Title Microstructure of α-axis oriented YBCO films on SrTiO3 substrates using a new template layer La4BaCu5O13 Type A1 Journal article
Year 1997 Publication Physica: C : superconductivity Abbreviated Journal Physica C
Volume 288 Issue Pages 231-242
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1997YE53600013 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4534 ISBN Additional Links UA library record; WoS full record;
Impact Factor 1.404 Times cited Open Access
Notes Approved Most recent IF: 1.404; 1997 IF: 2.199
Call Number UA @ lucian @ c:irua:22113 Serial 2063
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Author (down) Proost, J.; Blaffart, F.; Turner, S.; Idrissi, H.
Title On the Origin of Damped Electrochemical Oscillations at Silicon Anodes (Revisited) Type A1 Journal article
Year 2014 Publication ChemPhysChem : a European journal of chemical physics and physical chemistry Abbreviated Journal Chemphyschem
Volume 15 Issue 14 Pages 3116-3124
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Electrochemical oscillations accompanying the formation of anodic silica have been shown in the past to be correlated with rather abrupt changes in the mechanical stress state of the silica film, commonly associated with some kind of fracture or porosification of the oxide. To advance the understanding on the origin of such oscillations in fluoride-free electrolytes, we have revisited a seminal experiment reported by Lehmann almost two decades ago. We thereby demonstrate that the oscillations are not stress-induced, and do not originate from a morphological transformation of the oxide in the course of anodisation. Alternatively, the mechanical features accompanying the oscillations can be explained by a partial relaxation of the field-induced electrostrictive stress. Furthermore, our observations suggest that the oscillation mechanism more likely results from a periodic depolarisation of the anodic silica.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000342770500029 Publication Date 2014-08-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1439-4235; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.075 Times cited 5 Open Access
Notes Approved Most recent IF: 3.075; 2014 IF: 3.419
Call Number UA @ lucian @ c:irua:121086 Serial 2444
Permanent link to this record
 
 
Author (down) Prituzhalov, V.A.; Ardashnikova, E.I.; Vinogradov, A.A.; Dolgikh, V.A.; Videau, J.-J.; Fargin, E.; Abakumov, A.M.; Tarakina, N.V.; Van Tendeloo, G.
Title New anion-conducting solid solutions Bi1-xTex(O,F)2+\delta (x > 0.5) and glassceramic material on their base Type A1 Journal article
Year 2011 Publication Journal of fluorine chemistry Abbreviated Journal J Fluorine Chem
Volume 132 Issue 12 Pages 1110-1116
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The anion-excess fluorite-like solid solutions with general composition Bi1−xTex(O,F)2+δ (x > 0.5) have been synthesized by a solid state reaction of TeO2, BiF3 and Bi2O3 at 873 K with following quenching. The homogeneity areas and polymorphism of the I ↔ IV Bi1−xTex(O,F)2+δ phases were investigated. The crystal structure of the low temperature IV-Bi1−xTex(O,F)2+δ phase has been solved using electron diffraction and X-ray powder diffraction (a = 11.53051(9) Å, S.G. Ia-3, RI = 0.046, RP = 0.041). Glass formation area in the Bi2O3BiF3TeO2 (10% TiO2) system was investigated. IVBi1−xTex(O,F)2+δ phase starts to crystallize at short-time (0.53 h) annealing of oxyfluoride glasses at temperatures above Tg (600615 K). The ionic conductivity of the crystalline Bi1−xTex(O,F)2+δ phase and corresponding glass-ceramics was investigated. Activation energy of conductivity Ea = 0.41(2) eV for the IV-Bi1−xTex(O,F)2+δ crystalline samples and Ea = 0.73 eV for the glass-ceramic samples were obtained. Investigation of the oxyfluoride samples with a constant cation ratio demonstrates essential influence of excess fluorine anions on the ionic conductivity.
Address
Corporate Author Thesis
Publisher Place of Publication Lausanne Editor
Language Wos 000296936300011 Publication Date 2011-07-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-1139; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.101 Times cited 2 Open Access
Notes Approved Most recent IF: 2.101; 2011 IF: 2.033
Call Number UA @ lucian @ c:irua:93687 Serial 2305
Permanent link to this record
 
 
Author (down) Prituzhalov, V.A.; Abakumov, A.M.; Ardashnikova, E.I.; Dolgikh, V.A.; Van Tendeloo, G.
Title :Ba2.1Bi0.9(O, F)6.8-\delta: a new ordered anion-excess fluorite Type A1 Journal article
Year 2007 Publication Materials research bulletin Abbreviated Journal Mater Res Bull
Volume 42 Issue 5 Pages 861-869
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000245842600010 Publication Date 2006-10-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0025-5408; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.446 Times cited 4 Open Access
Notes Approved Most recent IF: 2.446; 2007 IF: 1.484
Call Number UA @ lucian @ c:irua:64724 Serial 3515
Permanent link to this record
 
 
Author (down) Pramanik, G.; Kvakova, K.; Thottappali, M.A.; Rais, D.; Pfleger, J.; Greben, M.; El-Zoka, A.; Bals, S.; Dracinsky, M.; Valenta, J.; Cigler, P.
Title Inverse heavy-atom effect in near infrared photoluminescent gold nanoclusters Type A1 Journal article
Year 2021 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 12 Issue 23 Pages 10462-10467
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Fluorophores functionalized with heavy elements show enhanced intersystem crossing due to increased spin-orbit coupling, which in turn shortens the fluorescence decay lifetime (tau(PL)). This phenomenon is known as the heavy-atom effect (HAE). Here, we report the observation of increased tau(PL) upon functionalisation of near-infrared photoluminescent gold nanoclusters with iodine. The heavy atom-mediated increase in tau(PL) is in striking contrast with the HAE and referred to as inverse HAE. Femtosecond and nanosecond transient absorption spectroscopy revealed overcompensation of a slight decrease in lifetime of the transition associated with the Au core (ps) by a large increase in the long-lived triplet state lifetime associated with the Au shell, which contributed to the observed inverse HAE. This unique observation of inverse HAE in gold nanoclusters provides the means to enhance the triplet excited state lifetime.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000657052500001 Publication Date 2021-06-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 1 Open Access OpenAccess
Notes The authors acknowledge support from GACR project no. 18-12533S. G. P. acknowledges support from EUSMI project no. E180200060; J. P. from the Ministry of Education, Youth and Sports of the Czech Republic – Program INTER-EXCELLENCE (LTAUSA19066). Approved Most recent IF: 7.367
Call Number UA @ admin @ c:irua:179052 Serial 6843
Permanent link to this record
 
 
Author (down) Pramanik, G.; Kvakova, K.; Thottappali, M.A.; Rais, D.; Pfleger, J.; Greben, M.; El-Zoka, A.; Bals, S.; Dracinsky, M.; Valenta, J.; Cigler, P.
Title Inverse heavy-atom effect in near infrared photoluminescent gold nanoclusters Type A1 Journal Article
Year 2021 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 13 Issue 23 Pages 10462-10467
Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Abstract Fluorophores functionalized with heavy elements show enhanced intersystem crossing due to increased spin–orbit coupling, which in turn shortens the fluorescence decay lifetime (<italic>τ</italic><sup>PL</sup>). This phenomenon is known as the heavy-atom effect (HAE). Here, we report the observation of increased<italic>τ</italic><sup>PL</sup>upon functionalisation of near-infrared photoluminescent gold nanoclusters with iodine. The heavy atom-mediated increase in<italic>τ</italic><sup>PL</sup>is in striking contrast with the HAE and referred to as inverse HAE. Femtosecond and nanosecond transient absorption spectroscopy revealed overcompensation of a slight decrease in lifetime of the transition associated with the Au core (ps) by a large increase in the long-lived triplet state lifetime associated with the Au shell, which contributed to the observed inverse HAE. This unique observation of inverse HAE in gold nanoclusters provides the means to enhance the triplet excited state lifetime.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2021-05-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364 ISBN Additional Links
Impact Factor 7.367 Times cited 7 Open Access OpenAccess
Notes The authors acknowledge support from GACR project Nr.18- 12533S. G. P. acknowledges support from EUSMI project No. E180200060; J.P. from the Ministry of Education, Youth and Sports of the Czech Republic – Program INTER-EXCELLENCE (LTAUSA19066). Approved Most recent IF: 7.367
Call Number EMAT @ emat @ Serial 6950
Permanent link to this record
 
 
Author (down) Pramanik, G.; Humpolickova, J.; Valenta, J.; Kundu, P.; Bals, S.; Bour, P.; Dracinsky, M.; Cigler, P.
Title Gold nanoclusters with bright near-infrared photoluminescence Type A1 Journal article
Year 2018 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 10 Issue 10 Pages 3792-3798
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The increase in nonradiative pathways with decreasing emission energy reduces the luminescence quantum yield (QY) of near-infrared photoluminescent (NIR PL) metal nanoclusters. Efficient surface ligand chemistry can significantly improve the luminescence QY of NIR PL metal nanoclusters. In contrast to the widely reported but modestly effective thiolate ligand-to-metal core charge transfer, we show that metal-to-ligand charge transfer (MLCT) can be used to greatly enhance the luminescence QY of NIR PL gold nanoclusters (AuNCs). We synthesized water-soluble and colloidally stable NIR PL AuNCs with unprecedentedly high QY (similar to 25%) upon introduction of triphenylphosphonium moieties into the surface capping layer. By using a combination of spectroscopic and theoretical methods, we provide evidence for gold core-to-ligand charge transfer occurring in AuNCs. We envision that this work can stimulate the development of these unusually bright AuNCs for promising optoelectronic, bioimaging, and other applications.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000426148500026 Publication Date 2018-01-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 97 Open Access OpenAccess
Notes ; The authors acknowledge support from the GACR project Nr. 18-12533S. J. V. acknowledges funding from the Ministry of Education, Youth and Sports of the Czech Republic via the V4+Japan project No. 8F15001 (cofinanced by the International Visegrad Fund). P. B. acknowledges GACR project No. 16-05935S and Ministry of Education, Youth and Sports of the Czech Republic project No. LTC17012. ; Approved Most recent IF: 7.367
Call Number UA @ lucian @ c:irua:149901UA @ admin @ c:irua:149901 Serial 4935
Permanent link to this record
 
 
Author (down) Prabhakara, V.; Nuytten, T.; Bender, H.; Vandervorst, W.; Bals, S.; Verbeeck, J.
Title Linearized radially polarized light for improved precision in strain measurements using micro-Raman spectroscopy Type A1 Journal article
Year 2021 Publication Optics Express Abbreviated Journal Opt Express
Volume 29 Issue 21 Pages 34531
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Strain engineering in semiconductor transistor devices has become vital in the semiconductor industry due to the ever-increasing need for performance enhancement at the nanoscale. Raman spectroscopy is a non-invasive measurement technique with high sensitivity to mechanical stress that does not require any special sample preparation procedures in comparison to characterization involving transmission electron microscopy (TEM), making it suitable for inline strain measurement in the semiconductor industry. Indeed, at present, strain measurements using Raman spectroscopy are already routinely carried out in semiconductor devices as it is cost effective, fast and non-destructive. In this paper we explore the usage of linearized radially polarized light as an excitation source, which does provide significantly enhanced accuracy and precision as compared to linearly polarized light for this application. Numerical simulations are done to quantitatively evaluate the electric field intensities that contribute to this enhanced sensitivity. We benchmark the experimental results against TEM diffraction-based techniques like nano-beam diffraction and Bessel diffraction. Differences between both approaches are assigned to strain relaxation due to sample thinning required in TEM setups, demonstrating the benefit of Raman for nondestructive inline testing.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000708940500144 Publication Date 2021-10-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1094-4087 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.307 Times cited 2 Open Access OpenAccess
Notes Horizon 2020 Framework Programme, 823717 – ESTEEM3 ; GOA project, “Solarpaint” ; Herculesstichting;; esteem3jra; esteem3reported; Approved Most recent IF: 3.307
Call Number EMAT @ emat @c:irua:182472 Serial 6816
Permanent link to this record
 
 
Author (down) Prabhakara, V.; Jannis, D.; Guzzinati, G.; Béché, A.; Bender, H.; Verbeeck, J.
Title HAADF-STEM block-scanning strategy for local measurement of strain at the nanoscale Type A1 Journal article
Year 2020 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 219 Issue Pages 113099
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Lattice strain measurement of nanoscale semiconductor devices is crucial for the semiconductor industry as strain substantially improves the electrical performance of transistors. High resolution scanning transmission electron microscopy (HR-STEM) imaging is an excellent tool that provides spatial resolution at the atomic scale and strain information by applying Geometric Phase Analysis or image fitting procedures. However, HR-STEM images regularly suffer from scanning distortions and sample drift during image acquisition. In this paper, we propose a new scanning strategy that drastically reduces artefacts due to drift and scanning distortion, along with extending the field of view. It consists of the acquisition of a series of independent small subimages containing an atomic resolution image of the local lattice. All subimages are then analysed individually for strain by fitting a nonlinear model to the lattice images. The method allows flexible tuning of spatial resolution and the field of view within the limits of the dynamic range of the scan engine while maintaining atomic resolution sampling within the subimages. The obtained experimental strain maps are quantitatively benchmarked against the Bessel diffraction technique. We demonstrate that the proposed scanning strategy approaches the performance of the diffraction technique while having the advantage that it does not require specialized diffraction cameras.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000594768500006 Publication Date 2020-09-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.2 Times cited 4 Open Access OpenAccess
Notes A.B. D.J. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. The Qu-Ant-EM microscope and the direct electron detector used in the diffraction experiments was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the GOA project “Solarpaint” of the University of Antwerp. GG acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek – Vlaanderen (FWO). Special thanks to Dr. Thomas Nuytten, Prof. Dr. Wilfried Vandervorst, Dr. Paola Favia, Dr. Olivier Richard from IMEC, Leuven and Prof. Dr. Sara Bals from EMAT, Antwerp for their continuous support and collaboration with the project and to the IMEC processing group for the device fabrication. Approved Most recent IF: 2.2; 2020 IF: 2.843
Call Number EMAT @ emat @c:irua:172485 Serial 6404
Permanent link to this record
 
 
Author (down) Prabhakara, V.; Jannis, D.; Béché, A.; Bender, H.; Verbeeck, J.
Title Strain measurement in semiconductor FinFET devices using a novel moiré demodulation technique Type A1 Journal article
Year 2019 Publication Semiconductor science and technology Abbreviated Journal Semicond Sci Tech
Volume Issue Pages
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Moiré fringes are used throughout a wide variety of applications in physics and

engineering to bring out small variations in an underlying lattice by comparing with another reference lattice. This method was recently demonstrated in Scanning Transmission Electron Microscopy imaging to provide local strain measurement in crystals by comparing the crystal lattice with the scanning raster that then serves as the reference. The images obtained in this way contain a beating fringe pattern with a local period that represents the deviation of the lattice from the reference. In order to obtain the actual strain value, a region containing a full period of the fringe is required, which results in a compromise between strain sensitivity and spatial resolution. In this paper we propose an advanced setup making use of an optimised scanning pattern and a novel phase stepping demodulation scheme. We demonstrate the novel method on a series of 16 nm Si-Ge semiconductor FinFET devices in which strain plays a crucial role in modulating the charge carrier mobility. The obtained results are compared with both Nano-beam diffraction and the recently proposed Bessel beam diffraction technique. The setup provides a much improved spatial resolution over conventional moiré imaging in STEM while at the same time being fast and requiring no specialised diffraction camera as opposed to the diffraction techniques we compare to.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000537721200002 Publication Date 2019-11-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0268-1242 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.305 Times cited 8 Open Access
Notes The Qu-Ant-EM microscope and the direct electron detector used in the diffraction experiments was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the GOA project “Solarpaint” of the University of Antwerp. We would also like to thank Dr. Thomas Nuytten and Prof. Dr. Wilfried Vandervorst from IMEC, Leuven for their continuous support and collaboration with the project. Approved Most recent IF: 2.305
Call Number EMAT @ emat @c:irua:165794 Serial 5445
Permanent link to this record
 
 
Author (down) Prabhakara, V.
Title Strain measurement for semiconductor applications with Raman spectroscopy and Transmission electron microscopy Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages 149 p.
Keywords Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Scaling down the size of transistors has been a trend for several decades which has led to improved transistor performance, increased transistor density and hence the overall computation power of IC chips. The trend slowed in recent years due to reliability and power consumption issues at the nanoscale. Hence strain is introduced into transistor channels that has beneficial effects on improving the mobility of charge carriers, providing an alternative pathway for enhancing transistor performance. Therefore, monitoring strain is vital for the semiconductor industry. With the recent trend of decreasing device dimensions (FinFETS ~ 10-20nm) and strain modulation being used throughout, industry needs a reliable and fast method as quality control or defect characterisation. Such a universal strain measurement method does not exist, and one relies on a combination of quantitative in-line methods and complex off-line approaches. In this thesis, I investigated TEM and Raman spectroscopy-based methodologies for strain measurement. In terms of TEM methodologies, advancements are made for the STEM moiré imaging, targeting strain spatial resolution enhancement. I introduce advanced quadrature demodulation and phase stepping interferometry applied to STEM moiré that greatly enhances the spatial resolution while providing enhanced field of view and sensitivity for strain measurement. We introduce ways to reduce scan distortions in strain maps using an alternative scan strategy called “Block scanning” and the non-linear regression applied for strain extraction. Prospects for 3D strain analysis using high-resolution tomography is also investigated which gives direct access for the full second order strain tensors calculation. Finally, we compare strain measurements from TEM techniques with inline techniques like Raman spectroscopy. Raman stress measurement involves sensitive identification of the TO and LO phonon peaks. Raman spectrum of strained Ge transistor channel consists of strongly overlapping peaks within the spectral resolution of the spectrometer. Hence, the process of deconvolution of the two peaks is rather challenging. Hence, we explore new polarisation geometries like radially polarised incoming light which was shown to ease the deconvolution problem resulting in improved precision for Raman stress–strain measurements.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:182261 Serial 6847
Permanent link to this record
 
 
Author (down) Pourbabak, S.; Wang, X.; Van Dyck, D.; Verlinden, B.; Schryvers, D.
Title Ni cluster formation in low temperature annealed Ni50.6Ti49.4 Type A1 Journal article
Year 2017 Publication Functional materials letters Abbreviated Journal Funct Mater Lett
Volume 10 Issue 10 Pages 1740005
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Various low temperature treatments of Ni50.6Ti49.4 have shown an unexpected effect on the martensitic start temperature. Periodic diffuse intensity distributions in reciprocal space indicate the formation of short pure Ni strings along the <111> directions in the B2 ordered lattice, precursing the formation of Ni4Ti3 precipitates formed at higher annealing temperatures.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000395164100006 Publication Date 2017-01-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1793-6047 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.234 Times cited 4 Open Access Not_Open_Access
Notes The authors like to thank the Flemish Science Foundation FWO for financial support under project G.0366.15N “Influence of nano- and microstructural features and defects in fine-grained Ni-Ti on the thermal and mechanical reversibility of the martensitic transformation and the shape memory and superelastic behavior”. We are also very grateful to Prof. Dr. Jan Van Humbeeck for initiating this work, for his continuous support and inspiring discussions. Approved Most recent IF: 1.234
Call Number EMAT @ emat @ c:irua:142545 Serial 4619
Permanent link to this record
 
 
Author (down) Pourbabak, S.; Verlinden, B.; Van Humbeeck, J.; Schryvers, D.
Title DSC cycling effects on phase transformation temperatures of micron and submicron grain Ni50.8Ti49.2 microwires Type A1 Journal article
Year 2020 Publication Shape memory and superelasticity Abbreviated Journal
Volume Issue Pages 1-10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The effect of thermal cycling parameters on the phase transformation temperatures of micron and submicron grain size recrystallized Ni-Ti microwires was investigated. The suppression of martensitic transformation by thermal cycling was found to enhance when combined with room temperature aging between the cycles and enhances even more when aged at elevated temperature of 100 degrees C. While aging at room temperature alone has no clear effect on the martensitic transformation, elevated temperature aging at 100 degrees C alone suppresses the martensitic transformation. All aforementioned effects were found to be stronger in large grain samples than in small grain samples. Martensitic transformation suppression in all cases was in line with the formation of Ni4Ti3 precursors in the form of < 111 & rang;(B2) Ni clusters as concluded from the observed diffuse intensity in the electron diffraction patterns revealing short-range ordering enhancement. Performing thermal cycling in some different temperature ranges to separate the effect of martensitic transformation and high temperature range of DSC cycling revealed that both high temperature- and martensitic transformation-included cycles enhance the short-range ordering.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000530232800001 Publication Date 2020-05-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2199-384x; 2199-3858 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 1 Open Access Not_Open_Access
Notes ; S.P. would like to thank the Flemish Science Foundation FWO for financial support under Project G.0366.15N. ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:169514 Serial 6492
Permanent link to this record
 
 
Author (down) Pourbabak, S.; Orekhov, A.; Schryvers, D.
Title Twin-jet electropolishing for damage-free transmission electron microscopy specimen preparation of metallic microwires Type A1 Journal article
Year 2020 Publication Microscopy Research And Technique Abbreviated Journal Microsc Res Techniq
Volume Issue Pages 1-7
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A method to prepare TEM specimens from metallic microwires and based on conventional twin-jet electropolishing is introduced. The wire is embedded in an opaque epoxy resin medium and the hardened resin is mechanically polished to reveal the wire on both sides. The resin containing wire is then cut into discs of the appropriate size. The obtained embedded wire is electropolished in a conventional twin-jet electropolishing machine until electron transparency in large areas without radiation damage is achieved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000567944200001 Publication Date 2020-09-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1059-910x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.5 Times cited Open Access OpenAccess
Notes ; Fonds Wetenschappelijk Onderzoek, Grant/Award Number: G.0366.15N ; Approved Most recent IF: 2.5; 2020 IF: 1.147
Call Number UA @ admin @ c:irua:171969 Serial 6642
Permanent link to this record
 
 
Author (down) Pourbabak, S.; Orekhov, A.; Samaee, V.; Verlinden, B.; Van Humbeeck, J.; Schryvers, D.
Title In-Situ TEM Stress Induced Martensitic Transformation in Ni50.8Ti49.2 Microwires Type A1 Journal article
Year 2019 Publication Shape memory and superelasticity Abbreviated Journal Shap. Mem. Superelasticity
Volume 5 Issue 2 Pages 154-162
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In-situ transmission electron microscopy tensile straining is used to study the stress induced martensitic transformation in Ni50.8Ti49.2. Two microwire samples with different heat treatment are investigated from which one single crystal and three polycrystalline TEM specimens, the latter with micro- and nano-size grains, have been produced. The measured Young’s modulus for all TEM specimens is around 70 GPa, considerably higher than the averaged 55 GPa of the original microwire sample. The height of the superelastic stress plateau shows an inverse relationship with the specimen thickness for the polycrystalline specimens. Martensite starts nucleating within the elastic region of the stress–strain curve and on the edges of the specimens while also grain boundaries act as nucleation sites in the polycrystalline specimens. When a martensite plate reaches a grain boundary in the polycrystalline specimen, it initiates the transformation in the neighboring grain at the other side of the grain boundary. In later stages martensite plates coalesce at higher loads in the stress plateau. In highly strained specimens, residual martensite remains after release.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000472940200002 Publication Date 2019-05-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2199-384X ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access Not_Open_Access
Notes Saeid Pourbabak likes to thank the Flemish Science Foundation FWO for financial support under Project G.0366.15N. This work was also made possible through the AUHA13009 Grant “TopSPIN for TEM nanostatistics” of the Flemish HERCULES foundation. Approved Most recent IF: NA
Call Number EMAT @ emat @UA @ admin @ c:irua:159989 Serial 5177
Permanent link to this record
 
 
Author (down) Pourbabak, S.; Montero-Sistiaga, M.L.; Schryvers, D.; Van Humbeeck, J.; Vanmeensel, K.
Title Microscopic investigation of as built and hot isostatic pressed Hastelloy X processed by Selective Laser Melting Type A1 Journal article
Year 2019 Publication Materials characterization Abbreviated Journal Mater Charact
Volume 153 Issue Pages 366-371
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Microstructural characteristics of Hastelloy X produced by Selective Laser Melting have been investigated by various microscopic techniques in the as built (AB) condition and after hot isostatic pressing (HIP). At sub-grain level the AB material consists of columnar high density dislocation cells while the HIP sample consists of columnar sub-grains with lower dislocation density that originate from the original dislocation cells, contradicting existing models. The sub-grains contain nanoscale precipitates enriched in Al, Ti, Cr and O, located at sub-grain boundaries in the AB condition and within the grains after HIP. At some grain boundaries, micrometer sized chromium carbides are detected after HIP. Micro hardness within the grains was found to decrease after HIP, which was attributed to the decrease in dislocation density due to recovery annealing.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000472696900040 Publication Date 2019-05-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1044-5803 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.714 Times cited 2 Open Access Not_Open_Access
Notes S.P. likes to thank the Flemish Science Foundation FWO for financial support under Project G.0366.15N. The authors acknowledge ENGIE Research and Technology Division for the use of the SLM280HL machine and financial support. This work was also made possible through the AUHA13009 grant “TopSPIN for TEM nanostatistics” of the Flemish HERCULES foundation. Approved Most recent IF: 2.714
Call Number EMAT @ emat @UA @ admin @ c:irua:159974 Serial 5178
Permanent link to this record
 
 
Author (down) Pourbabak, S.
Title Influence of nano and microstructural features and defects in finegrained NiTi on the thermal and mechanical reversibility of the martensitic transformation Type Doctoral thesis
Year 2020 Publication Abbreviated Journal
Volume Issue Pages 166 p.
Keywords Doctoral thesis; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:165919 Serial 6305
Permanent link to this record
 
 
Author (down) Poulain, R.; Lumbeeck, G.; Hunka, J.; Proost, J.; Savolainen, H.; Idrissi, H.; Schryvers, D.; Gauquelin, N.; Klein, A.
Title Electronic and chemical properties of nickel oxide thin films and the intrinsic defects compensation mechanism Type A1 Journal article
Year 2022 Publication ACS applied electronic materials Abbreviated Journal
Volume 4 Issue 6 Pages 2718-2728
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Although largely studied, contradictory results on nickel oxide (NiO) properties can be found in the literature. We herein propose a comprehensive study that aims at leveling contradictions related to NiO materials with a focus on its conductivity, surface properties, and the intrinsic charge defects compensation mechanism with regards to the conditions preparation. The experiments were performed by in situ photo-electron spectroscopy, electron energy loss spectroscopy, and optical as well as electrical measurements on polycrystalline NiO thin films prepared under various preparation conditions by reactive sputtering. The results show that surface and bulk properties were strongly related to the deposition temperature with in particular the observation of Fermi level pinning, high work function, and unstable oxygen-rich grain boundaries for the thin films produced at room temperature but not at high temperature (>200 degrees C). Finally, this study provides substantial information about surface and bulk NiO properties enabling to unveil the origin of the high electrical conductivity of room temperature NiO thin films and also for supporting a general electronic charge compensation mechanism of intrinsic defects according to the deposition temperature.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000819431200001 Publication Date 2022-06-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2637-6113 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:189555 Serial 7081
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