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Author Xu, P.; Qi, D.; Schoelz, J.K.; Thompson, J.; Thibado, P.M.; Wheeler, V.D.; Nyakiti, L.O.; Myers-Ward, R.L.; Eddy, C.R.; Gaskill, D.K.; Neek-Amal, M.; Peeters, F.M.;
Title Multilayer graphene, Moire patterns, grain boundaries and defects identified by scanning tunneling microscopy on the m-plane, non-polar surface of SiC Type A1 Journal article
Year 2014 Publication Carbon Abbreviated Journal Carbon
Volume 80 Issue Pages 75-81
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Epitaxial graphene is grown on a non-polar n(+) 6H-SiC m-plane substrate and studied using atomic scale scanning tunneling microscopy. Multilayer graphene is found throughout the surface and exhibits rotational disorder. Moire patterns of different spatial periodicities are found, and we found that as the wavelength increases, so does the amplitude of the modulations. This relationship reveals information about the interplay between the energy required to bend graphene and the interaction energy, i.e. van der Waals energy, with the graphene layer below. Our experiments are supported by theoretical calculations which predict that the membrane topographical amplitude scales with the Moire pattern wavelength, L as L-1 + alpha L-2. (C) 2014 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000344132400009 Publication Date 2014-08-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0008-6223; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.337 Times cited 14 Open Access
Notes ; P.X. and P.M.T. gratefully acknowledge the financial support of ONR under grant N00014-10-1-0181 and NSF under grant DMR-0855358. L.O.N. acknowledges the support of American Society for Engineering Education and Naval Research Laboratory Postdoctoral Fellow Program. Work at the U.S. Naval Research Laboratory is supported by the Office of Naval Research. This work was supported by the Flemish Science Foundation (FWO-Vl), the Methusalem Foundation of the Flemish Government, and the EUROgraphene project CONGRAN. M.N.-A was supported by the EU-Marie Curie IIF postdoc Fellowship 299855. ; Approved Most recent IF: 6.337; 2014 IF: 6.196
Call Number UA @ lucian @ c:irua:121194 Serial 2221
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Author Bertels, E.; Bruyninckx, K.; Kurttepeli; Smet, M.; Bals, S.; Goderis, B.
Title Highly Efficient Hyperbranched CNT Surfactants: Influence of Molar Mass and Functionalization Type A1 Journal article
Year 2014 Publication Langmuir: the ACS journal of surfaces and colloids Abbreviated Journal Langmuir
Volume 30 Issue 41 Pages 12200-12209
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (down) End-group-functionalized hyperbranched polymers were synthesized to act as a carbon nanotube (CNT) surfactant in aqueous solutions. Variation of the percentage of triphenylmethyl (trityl) functionalization and of the molar mass of the hyperbranched polyglycerol (PG) core resulted in the highest measured surfactant efficiency for a 5000 g/mol PG with 5.6% of the available hydroxyl end-groups replaced by trityl functions, as shown by UV-vis measurements. Semiempirical model calculations suggest an even higher efficiency for PG5000 with 2.5% functionalization and maximal molecule specific efficiency in general at low degrees of functionalization. Addition of trityl groups increases the surfactant-nanotube interactions in comparison to unfunctionalized PG because of pi-pi stacking interactions. However, at higher functionalization degrees mutual interactions between trityl groups come into play, decreasing the surfactant efficiency, while lack of water solubility becomes an issue at very high functionalization degrees. Low molar mass surfactants are less efficient compared to higher molar mass species most likely because the higher bulkiness of the latter allows for a better CNT separation and stabilization. The most efficient surfactant studied allowed dispersing 2.85 mg of CNT in 20 mL with as little as 1 mg of surfactant. These dispersions, remaining stable for at least 2 months, were mainly composed of individual CNTs as revealed by electron microscopy.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000343638800013 Publication Date 2014-09-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0743-7463;1520-5827; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.833 Times cited 15 Open Access OpenAccess
Notes The authors gratefully acknowledge the SIM NanoForce programme for their financial support and thank the group of Prof. Thierry Verbiest, especially Maarten Bloemen, for the use of their UV−vis equipment. Bart Goderis and Mario Smet thank KU Leuven for financial support through a GOA project. Mert Kurttepeli and Sara Bals acknowledge funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant No. 335078 COLOURATOMS.; ECAS_Sara; (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); Approved Most recent IF: 3.833; 2014 IF: 4.457
Call Number UA @ lucian @ c:irua:121140 Serial 1471
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Author Arana, A.; Loureiro, A.L.; Barbosa, H.M.J.; Van Grieken, R.; Artaxo, P.
Title Optimized energy dispersive X-ray fluorescence analysis of atmospheric aerosols collected at pristine and perturbed Amazon Basin sites Type A1 Journal article
Year 2014 Publication X-ray spectrometry Abbreviated Journal
Volume 43 Issue 4 Pages 228-237
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) Elemental composition of aerosols is important to source apportionment studies and to understand atmospheric processes that influence aerosol composition. Energy dispersive X-ray fluorescence spectroscopy was applied for measuring the elemental composition of Amazonian atmospheric aerosols. The instrument used was a spectrometer Epsilon 5, PANalytical B. V., with tridimensional geometry that reduces the background signal with a polarized X-ray detection. The measurement conditions were optimized for low-Z elements, e. g. Mg, Al, Si, that are present at very low concentrations in the Amazon. From Na to K, our detection limits are about 50% to 75% lower than previously published results for similar instrument. Calibration was performed using Micromatter standards, except for P whose standard was produced by nebulization of an aqueous solution of KH2PO4 at our laboratory. The multi-element reference material National Institute of Standards and Technology-2783 (air particulate filter) was used for evaluating the accuracy of the calibration procedure of the 22 elements in our standard analysis routine, and the uncertainty associated with calibration procedures was evaluated. The overall performance of the instrument and validation of our measurements were assessed by comparison with results obtained from parallel analysis using particle-induced X-ray emission and another Epsilon 5 spectrometer. The elemental composition in 660 samples collected at a pristine site in the Amazon Basin and of 1416 samples collected at a site perturbed by land use change was determined. Our measurements show trace elements associated with biogenic aerosols, soil dust, biomass burning, and sea-salt, even for the very low concentrations as observed in Amazonia. Copyright (C) 2014 John Wiley & Sons, Ltd.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000337724600006 Publication Date 2014-06-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0049-8246 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:118419 Serial 8342
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Author Clark, L.; Béché, A.; Guzzinati, G.; Verbeeck, J.
Title Quantitative measurement of orbital angular momentum in electron microscopy Type A1 Journal article
Year 2014 Publication Physical review : A : atomic, molecular and optical physics Abbreviated Journal Phys Rev A
Volume 89 Issue 5 Pages 053818
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (down) Electron vortex beams have been predicted to enable atomic scale magnetic information measurement, via transfer of orbital angular momentum. Research so far has focused on developing production techniques and applications of these beams. However, methods to measure the outgoing orbital angular momentum distribution are also a crucial requirement towards this goal. Here, we use a method to obtain the orbital angular momentum decomposition of an electron beam, using a multipinhole interferometer. We demonstrate both its ability to accurately measure orbital angular momentum distribution, and its experimental limitations when used in a transmission electron microscope.
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Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000335826300012 Publication Date 2014-05-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1050-2947;1094-1622; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.925 Times cited 23 Open Access
Notes 7th Framework Program (FP7); ERC Starting Grant No. 278510- VORTEX 7th Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative (Reference No. 312483 ESTEEM2). 7th Framework Program (FP7), ERC Grant No. 246791- COUNTATOMS. SP – 053818-1; esteem2jra3 ECASJO; Approved Most recent IF: 2.925; 2014 IF: 2.808
Call Number UA @ lucian @ c:irua:117093UA @ admin @ c:irua:117093 Serial 2758
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Author 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 (down) 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
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Author Schütte, K.; Doddi, A.; Kroll, C.; Meyer, H.; Wiktor, C.; Gemel, C.; Van Tendeloo, G.; Fischer, R.A.; Janiak, C.
Title Colloidal nickel/gallium nanoalloys obtained from organometallic precursors in conventional organic solvents and in ionic liquids : noble-metal-free alkyne semihydrogenation catalysts Type A1 Journal article
Year 2014 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 6 Issue 10 Pages 5532-5544
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) Efforts to replace noble-metal catalysts by low-cost alternatives are of constant interest. The organometallic, non-aqueous wet-chemical synthesis of various hitherto unknown nanocrystalline Ni/Ga intermetallic materials and the use of NiGa for the selective semihydrogenation of alkynes to alkenes are reported. Thermal co-hydrogenolysis of the all-hydrocarbon precursors [Ni(COD)(2)] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in high-boiling organic solvents mesitylene and n-decane in molar ratios of 1 : 1, 2 : 3 and 3 : 1 yields the nano-crystalline powder materials of the over-all compositions NiGa, Ni2Ga3 and Ni3Ga, respectively. Microwave induced co-pyrolysis of the same precursors without additional hydrogen in the ionic liquid [BMIm][BF4] (BMIm = 1-butyl-3-methyl-imidazolium) selectively yields the intermetallic phases NiGa and Ni3Ga from the respective 1 : 1 and 3 : 1 molar ratios of the precursors. The obtained materials are characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), IR, powder X-ray diffraction (PXRD) and atomic absorption spectroscopy (AAS). The single-source precursor [Ni(GaCp*)(PMe3)(3)] with a fixed Ni : Ga stoichiometry of 1 : 1 was employed as well. In comparison with the co-hydrogenolytic dual precursor source approach it turned out to be less practical due to inefficient nickel incorporation caused by the parasitic formation of stable [Ni(PMe3)(4)]. The use of ionic liquid [BMIm][BF4] as a non-conventional solvent to control the reaction and stabilize the nanoparticles proved to be particularly advantageous and stable colloids of the nanoalloys NiGa and Ni3Ga were obtained. A phase-selective Ni/Ga colloid synthesis in conventional solvents and in the presence of surfactants such as hexadecylamine (HDA) was not feasible due to the undesired reactivity of HDA with GaCp* leading to inefficient gallium incorporation. Recyclable NiGa nanoparticles selectively semihydrogenate 1-octyne and diphenylacetylene (tolan) to 1-octene and diphenylethylene, respectively, with a yield of about 90% and selectivities of up to 94 and 87%. Ni-NPs yield alkanes with a selectivity of 97 or 78%, respectively, under the same conditions.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000335148800069 Publication Date 2014-03-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 40 Open Access
Notes Approved Most recent IF: 7.367; 2014 IF: 7.394
Call Number UA @ lucian @ c:irua:117251 Serial 390
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Author Vanschoenwinkel, J.; Lizin, S.; Swinnen, G.; Azadi, H.; Van Passel, S.
Title Solar cooking in Senegalese villages : an application of best-worst scaling Type A1 Journal article
Year 2014 Publication Energy Policy Abbreviated Journal Energ Policy
Volume 67 Issue Pages 447-458
Keywords A1 Journal article; Sociology; Engineering sciences. Technology; Engineering Management (ENM)
Abstract (down) Dissemination programs of nontraditional cookstoves often fail. Nontraditional cookstoves aim to solve problems associated with biomass fuel usage in developing countries. Recent studies do not explain what drives user's cookstove choice. This study therefore builds a holistic framework that centralizes product-specific preferences or needs. The case study identifies product-specific factors that influence rural Senegalese inhabitants to switch to solar cooking, using best worst scaling. Looking at the preferences, the case study classified 126 respondents, in three distinct market segments with different solar cooking expectations. The paper identifies socio-demographic characteristics that explain these differences in the respondents' preferences. Finally, the respondent sample is divided in two groups: solar cooker owners and non-owners. When studied with regard to the same issue, solar cooker owners appear to value benefits of the solar cooker lower than non-owners. This is due to program factors (such as formations, after-sales network) and miscommunication (such as a wrong image of the solar cooker) that highly influenced the respondents' cookstove choice. As a conclusion, solar cookers and solar cooking programs are not always adapted to the needs and requirements of the end-users. Needs-oriented and end-user adopted strategies are necessary in order to successfully implement nontraditional cookstoves programs. (C) 2013 Elsevier Ltd. All rights reserved.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000332815300043 Publication Date 2014-01-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0301-4215; 1873-6777 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.14 Times cited 10 Open Access
Notes ; The authors thank the VLIR-UOS for their financial support and the Sol Suffit Program for their co-operation during the research. ; Approved Most recent IF: 4.14; 2014 IF: 2.575
Call Number UA @ admin @ c:irua:127544 Serial 6251
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Author Lucena, D.; Galván Moya, J.E.; Ferreira, W.P.; Peeters, F.M.
Title Single-file and normal diffusion of magnetic colloids in modulated channels Type A1 Journal article
Year 2014 Publication Physical review : E : statistical, nonlinear, and soft matter physics Abbreviated Journal Phys Rev E
Volume 89 Issue 3 Pages 032306-32309
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Diffusive properties of interacting magnetic dipoles confined in a parabolic narrow channel and in the presence of a periodic modulated (corrugated) potential along the unconfined direction are studied using Brownian dynamics simulations. We compare our simulation results with the analytical result for the effective diffusion coefficient of a single particle by Festa and d'Agliano [Physica A 90, 229 (1978)] and show the importance of interparticle interaction on the diffusion process. We present results for the diffusion of magnetic dipoles as a function of linear density, strength of the periodic modulation and commensurability factor.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication Woodbury (NY) Editor
Language Wos 000333646400005 Publication Date 2014-03-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1539-3755;1550-2376; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.366 Times cited 5 Open Access
Notes ; This work was supported by CNPq, CAPES, FUNCAP (Pronex grant), the Flemish Science Foundation (FWO-Vl), the collaborative program CNPq-FWO-Vl, and the Brazilian program Science Without Borders (CsF). D. Lucena acknowledges fruitful discussions with W. A. Munoz, V. F. Becerra, E. C. Euan-Diaz, and M. R. Masir. ; Approved Most recent IF: 2.366; 2014 IF: 2.288
Call Number UA @ lucian @ c:irua:116865 Serial 3020
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Author Zhang, F.; Vanmeensel, K.; Inokoshi, M.; Batuk, M.; Hadermann, J.; Van Meerbeek, B.; Naert, I.; Vleugels, J.
Title 3Y-TZP ceramics with improved hydrothermal degradation resistance and fracture toughness Type A1 Journal article
Year 2014 Publication Journal of the European Ceramic Society Abbreviated Journal J Eur Ceram Soc
Volume 34 Issue 10 Pages 2453-2463
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (down) Different factors such as the way of incorporating the Y2O3 stabilizer, alumina addition and sintering temperature were assessed with the goal to improve the low temperature degradation (LTD) resistance of 3Y-TZP without compromising on the mechanical properties. The degradation of hydrothermally treated specimens was studied by X-ray diffraction, micro-Raman spectroscopy and scanning electron microscopy. Decreasing the sintering temperature decreased the LTD susceptibility of 3Y-TZPs but did not allow to obtain a LTD resistant 3Y-TZP with optimized mechanical properties. Alumina addition along with the use of Y2O3 stabilizer coated starting powder allowed to combine both an excellent toughness and LTD resistance, as compared to alumina-free and stabilizer co-precipitated powder based equivalents. Transmission electron microscopy revealed that the improved LTD resistance could be attributed to the segregation of Al3+ at the grain boundary and the heterogeneously distributed Y3+ stabilizer.
Address
Corporate Author Thesis
Publisher Place of Publication Barking Editor
Language Wos 000336352500033 Publication Date 2014-03-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0955-2219; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 48 Open Access
Notes Fwo G.0431.10n Approved Most recent IF: 3.411; 2014 IF: 2.947
Call Number UA @ lucian @ c:irua:117065 c:irua:117065 Serial 11
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Author Van Eynde, E.; Lenaerts, B.; Tytgat, T.; Verbruggen, S.W.; Hauchecorne, B.; Blust, R.; Lenaerts, S.
Title Effect of pretreatment and temperature on the properties of Pinnularia biosilica frustules Type A1 Journal article
Year 2014 Publication RSC advances Abbreviated Journal Rsc Adv
Volume 4 Issue Pages 56200-56206
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) Diatoms are unicellular microalgae that self-assemble an intricate porous silica cell wall, called frustule. Diatom frustules possess a unique combination of physical and chemical properties (chemical inertness, high mechanical strength, large surface area, low density, good porosity and highly ordered features on the nano-to-micro scale) making diatom frustules suited for many nanotechnological applications. For most proposed applications the organic material covering the frustules needs to be removed. In this paper we investigate the effect of different frustule cleaning methods (drying, autoclavation, SDS/EDTA treatment, H2O2 treatment and HNO3 treatment) and subsequent heat treatment at different temperatures (105 °C, 350 °C, 550 °C and 750 °C) on the material characteristics of the diatom Pinnularia sp. Material characteristics under study are morphology, surface area, pore size, elemental composition and organic content. The cleaned Pinnularia frustules are subsequently investigated as adsorbents to remove methylene blue (MB) from aqueous solution.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000344997800060 Publication Date 2014-10-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2046-2069 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.108 Times cited 10 Open Access
Notes ; ; Approved Most recent IF: 3.108; 2014 IF: 3.840
Call Number UA @ admin @ c:irua:121377 Serial 5945
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Author Lin, S.-H.; Milošević, M.V.; Covaci, L.; Janko, B.; Peeters, F.M.
Title Quantum rotor in nanostructured superconductors Type A1 Journal article
Year 2014 Publication Scientific reports Abbreviated Journal Sci Rep-Uk
Volume 4 Issue Pages 4542-4546
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) Despite its apparent simplicity, the idealized model of a particle constrained to move on a circle has intriguing dynamic properties and immediate experimental relevance. While a rotor is rather easy to set up classically, the quantum regime is harder to realize and investigate. Here we demonstrate that the quantum dynamics of quasiparticles in certain classes of nanostructured superconductors can be mapped onto a quantum rotor. Furthermore, we provide a straightforward experimental procedure to convert this nanoscale superconducting rotor into a regular or inverted quantum pendulum with tunable gravitational field, inertia, and drive. We detail how these novel states can be detected via scanning tunneling spectroscopy. The proposed experiments will provide insights into quantum dynamics and quantum chaos.
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Corporate Author Thesis
Publisher Nature Publishing Group Place of Publication London Editor
Language Wos 000333555300007 Publication Date 2014-04-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.259 Times cited 4 Open Access
Notes ; The work was supported by the Flemish Science Foundation (FWO-Vl), the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract W-31-109-Eng-38, and the US National Science Foundation via NSF-NIRT ECS-0609249. ; Approved Most recent IF: 4.259; 2014 IF: 5.578
Call Number UA @ lucian @ c:irua:116848 Serial 2785
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Author van Oers, C.J.; Kurttepeli, M.; Mertens, M.; Bals, S.; Meynen, V.; Cool, P.
Title Zeolite \beta nanoparticles based bimodal structures : mechanism and tuning of the porosity and zeolitic properties Type A1 Journal article
Year 2014 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume 185 Issue Pages 204-212
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract (down) Despite great efforts in the research area of zeolite nanoparticles and their use in the synthesis of bimodal materials, still little is known about the impact of the synthesis conditions of the zeolite nanoparticles on its own characteristics, and on the properties and the formation mechanism of the final bimodal materials. A zeolite β nanoparticles solution is applied in a mesotemplate-free synthesis method, and the influence of the hydrothermal ageing temperature of the nanoparticles solution on both the zeolitic and porosity characteristics of the final bimodal material has been studied. Transmission electron microscopy in combination with 3-dimensional reconstructions obtained by electron tomography revealed that the zeolite β nanoparticles are connected by neck-like structures, thus creating a wormhole-like mesoporous material. Considering the zeolitic properties, a clear threshold is observed in the synthesis temperature series at 413 K. Below and at this threshold, the biporous materials show no apparent zeolitic characteristics, although these materials exhibit a more condensed and uniform SiOSi network in comparison to Al-MCF. Synthesis temperatures above the threshold lead to bimodal structures with defined zeolitic properties. Moreover, the dimensions of the nanoparticles are studied by TEM, revealing an increasing particle size with increasing temperature under the threshold of 413 K, which is in agreement with a sol-mechanism. This mechanism is disturbed after the threshold due to the start of the crystallisation process.
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Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000330930400025 Publication Date 2013-11-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 10 Open Access OpenAccess
Notes 262348 Esmi Approved Most recent IF: 3.615; 2014 IF: 3.453
Call Number UA @ lucian @ c:irua:112501 Serial 3930
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Author Lubk, A.; Javon, E.; Cherkashin, N.; Reboh, S.; Gatel, C.; Hytch, M.
Title Dynamic scattering theory for dark-field electron holography of 3D strain fields Type A1 Journal article
Year 2014 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 136 Issue Pages 42-49
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (down) Dark-held electron holography maps strain in crystal lattices into reconstructed phases over large fields of view. Here we investigate the details of the lattice strain-reconstructed phase relationship by applying dynamic scattering theory both analytically and numerically. We develop efficient analytic linear projection rules for 3D strain fields, facilitating a straight-forward calculation of reconstructed phases from 3D strained materials. They are used in the following to quantify the influence of various experimental parameters like strain magnitude, specimen thickness, excitation error and surface relaxation. (C) 2013 Elsevier B.V. All rights reserved.
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Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000327884700006 Publication Date 2013-07-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 18 Open Access
Notes European Union under the Seventh Framework Program under a contract for an Integrated Infrastructure Initiative (Reference312483 – ESTEEM2); esteem2_jra4 Approved Most recent IF: 2.843; 2014 IF: 2.436
Call Number UA @ lucian @ c:irua:112836 Serial 766
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Author Tinck, S.; Neyts, E.C.; Bogaerts, A.
Title Fluorinesilicon surface reactions during cryogenic and near room temperature etching Type A1 Journal article
Year 2014 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 118 Issue 51 Pages 30315-30324
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) Cyrogenic etching of silicon is envisaged to enable better control over plasma processing in the microelectronics industry, albeit little is known about the fundamental differences compared to the room temperature process. We here present molecular dynamics simulations carried out to obtain sticking probabilities, thermal desorption rates, surface diffusion speeds, and sputter yields of F, F2, Si, SiF, SiF2, SiF3, SiF4, and the corresponding ions on Si(100) and on SiF13 surfaces, both at cryogenic and near room temperature. The different surface behavior during conventional etching and cryoetching is discussed. F2 is found to be relatively reactive compared to other species like SiF03. Thermal desorption occurs at a significantly lower rate under cryogenic conditions, which results in an accumulation of physisorbed species. Moreover, ion incorporation is often observed for ions with energies of 30400 eV, which results in a relatively low net sputter yield. The obtained results suggest that the actual etching of Si, under both cryogenic and near room temperature conditions, is based on the complete conversion of the Si surface to physisorbed SiF4, followed by subsequent sputtering of these molecules, instead of direct sputtering of the SiF03 surface.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000347360200101 Publication Date 2014-11-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 11 Open Access
Notes Approved Most recent IF: 4.536; 2014 IF: 4.772
Call Number UA @ lucian @ c:irua:122957 Serial 1239
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Author Hutter, E.M.; Bladt, E.; Goris, B.; Pietra, F.; van der Bok, J.C.; Boneschanscher, M.P.; de Donega, C.M.; Bals, S.; Vanmaekelbergh, D.
Title Conformal and atomic characterization of ultrathin CdSe platelets with a helical shape Type A1 Journal article
Year 2014 Publication Nano letters Abbreviated Journal Nano Lett
Volume 14 Issue 11 Pages 6257-6262
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) Currently, ultrathin colloidal CdSe semiconductor nanoplatelets (NPLs) with a uniform thickness that is controllable up to the atomic scale can be prepared. The optical properties of these 2D semiconductor systems are the subject of extensive research. Here, we reveal their natural morphology and atomic arrangement. Using cryo-TEM (cryo-transmission electron microscopy), we show that the shape of rectangular NPLs in solution resembles a helix. Fast incorporation of these NPLs in silica preserves and immobilizes their helical shape, which allowed us to perform an in-depth study by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). Electron tomography measurements confirm and detail the helical shape of these systems. Additionally, high-resolution HAADF-STEM shows the thickness of the NPLs on the atomic scale and furthermore that these are consistently folded along a ?110? direction. The presence of a silica shell on both the top and bottom surfaces shows that Cd atoms must be accessible for silica precursor (and ligand) molecules on both sides.
Address
Corporate Author Thesis
Publisher Place of Publication Washington Editor
Language Wos 000345723800036 Publication Date 2014-10-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.712 Times cited 43 Open Access OpenAccess
Notes Dariusz Mitoraj, Hans Meeldijk, Relinde van Dijk-Moes, and Stephan Zevenhuizen are acknowledged for technical support and help with some experiments. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement no. 291667. The authors acknowledge financial support from FOM and NOW [FOM program Functional NanoParticle Solids (FNPS)]. S.B. acknowledges financial support from European Research Council (ERC Starting Grant #335078- COLOURATOMS). E.B. and B.G. gratefully acknowledge financial support by the Flemish Fund for Scientific Research (FWO Vlaanderen).; ECAS_Sara; (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); Approved Most recent IF: 12.712; 2014 IF: 13.592
Call Number UA @ lucian @ c:irua:122209 Serial 490
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Author Buffière, M.; Brammertz, G.; Oueslati, S.; El Anzeery, H.; Bekaert, J.; Ben Messaoud, K.; Köble, C.; Khelifi, S.; Meuris, M.; Poortmans, J.
Title Spectral current-voltage analysis of kesterite solar cells Type A1 Journal article
Year 2014 Publication Journal Of Physics D-Applied Physics Abbreviated Journal J Phys D Appl Phys
Volume 47 Issue 17 Pages 175101-175105
Keywords A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Abstract (down) Current-voltage analysis using different optical band pass filters has been performed on Cu2ZnSnSe4 and Cu2ZnSn(S, Se)(4) thin-film solar cells. When using red or orange light (i.e. wavelengths above 600 nm), a distortion appears in the I-V curve of the Cu2ZnSnSe4 solar cell, indicating an additional potential barrier to the current flow in the device for these conditions of illumination. This barrier is reduced when using a Cu2ZnSn(S, Se)(4) absorber. Numerical simulations demonstrate that the barrier visible under red light could be explained by a positive conduction band offset at the front interface coupled with compensating defects in the buffer layer.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000334504800003 Publication Date 2014-04-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727;1361-6463; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 25 Open Access
Notes Approved Most recent IF: 2.588; 2014 IF: 2.721
Call Number UA @ lucian @ c:irua:117170 Serial 3070
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Author Batuk, M.; Turner, S.; Abakumov, A.M.; Batuk, D.; Hadermann, J.; Van Tendeloo, G.
Title Atomic structure of defects in anion-deficient perovskite-based ferrites with a crystallographic shear structure Type A1 Journal article
Year 2014 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 53 Issue 4 Pages 2171-2180
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (down) Crystallographic shear (CS) planes provide a new structure-generation mechanism in the anion-deficient perovskites containing lone-pair cations. Pb2Sr2Bi2Fe6O16, a new n = 6 representative of the AnBnO3n2 homologous series of the perovskite-based ferrites with the CS structure, has been synthesized using the solid-state technique. The structure is built of perovskite blocks with a thickness of four FeO6 octahedra spaced by double columns of FeO5 edge-sharing distorted tetragonal pyramids, forming 1/2[110](101)p CS planes (space group Pnma, a = 5.6690(2) Å, b = 3.9108(1) Å, c = 32.643(1) Å). Pb2Sr2Bi2Fe6O16 features a wealth of microstructural phenomena caused by the flexibility of the CS planes due to the variable ratio and length of the constituting fragments with {101}p and {001}p orientation. This leads to the formation of waves, hairpins, Γ-shaped defects, and inclusions of the hitherto unknown layered anion-deficient perovskites Bi2(Sr,Pb)Fe3O8.5 and Bi3(Sr,Pb)Fe4O11.5. Using a combination of diffraction, imaging, and spectroscopic transmission electron microscopy techniques this complex microstructure was fully characterized, including direct determination of positions, chemical composition, and coordination number of individual atomic species. The complex defect structure makes these perovskites particularly similar to the CS structures in ReO3-type oxides. The flexibility of the CS planes appears to be a specific feature of the Sr-based system, related to the geometric match between the SrO perovskite layers and the {100}p segments of the CS planes.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000332144100039 Publication Date 2014-01-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.857 Times cited 6 Open Access
Notes Countatoms; FWO Approved Most recent IF: 4.857; 2014 IF: 4.762
Call Number UA @ lucian @ c:irua:113507 Serial 198
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Author Gaouyat, L.; He, Z.; Colomer, J.-F.; Lambin, P.; Mirabella, F.; Schryvers, D.; Deparis, O.
Title Revealing the innermost nanostructure of sputtered NiCrOx solar absorber cermets Type A1 Journal article
Year 2014 Publication Solar energy materials and solar cells Abbreviated Journal Sol Energ Mat Sol C
Volume 122 Issue Pages 303-308
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) Conversion of solar energy into thermal energy helps reducing consumption of non-renewable energies. Cermets (ceramicmetal composites) are versatile materials suitable, amongst other applications, for solar selective absorbers. Although the presence of metallic Ni particles in the dielectric matrix is a prerequisite for efficient solar selective absorption in NiCrOx cermets, no clear evidence of such particles is reported so far. By combining comprehensive chemical and structural analyses, we reveal the presumed nanostructure which is at the origin of the remarkable optical properties of this cermet material. Using sputtered NiCrOx layers in a solar absorber multilayer stack on aluminium substrate allows us to achieve solar absorptance as high as α=96.1% while keeping thermal emissivity as low as ε=2.2%, both values being comparable to best values recorded so far. With the nanostructure of sputtered NiCrOx cermets eventually revealed, further optimization of solar absorbers can be anticipated and technological exploitation of cermet materials in other applications can be foreseen.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000331494200040 Publication Date 2013-11-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0927-0248; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.784 Times cited 12 Open Access
Notes Approved Most recent IF: 4.784; 2014 IF: 5.337
Call Number UA @ lucian @ c:irua:113086 Serial 2902
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Author Shen, Y.; Turner, S.; Yang, P.; Van Tendeloo, G.; Lebedev, O.I.; Wu, T.
Title Epitaxy-enabled vapor-liquid-solid growth of tin-doped indium oxide nanowires with controlled orientations Type A1 Journal article
Year 2014 Publication Nano letters Abbreviated Journal Nano Lett
Volume 14 Issue 8 Pages 4342-4351
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) Controlling the morphology of nanowires in bottom-up synthesis and assembling them on planar substrates is of tremendous importance for device applications in electronics, photonics, sensing and energy conversion. To date, however, there remain challenges in reliably achieving these goals of orientation-controlled nanowire synthesis and assembly. Here we report that growth of planar, vertical and randomly oriented tin-doped indium oxide (ITO) nanowires can be realized on yttria-stabilized zirconia (YSZ) substrates via the epitaxy-assisted vaporliquidsolid (VLS) mechanism, by simply regulating the growth conditions, in particular the growth temperature. This robust control on nanowire orientation is facilitated by the small lattice mismatch of 1.6% between ITO and YSZ. Further control of the orientation, symmetry and shape of the nanowires can be achieved by using YSZ substrates with (110) and (111), in addition to (100) surfaces. Based on these insights, we succeed in growing regular arrays of planar ITO nanowires from patterned catalyst nanoparticles. Overall, our discovery of unprecedented orientation control in ITO nanowires advances the general VLS synthesis, providing a robust epitaxy-based approach toward rational synthesis of nanowires.
Address
Corporate Author Thesis
Publisher Place of Publication Washington Editor
Language Wos 000340446200022 Publication Date 2014-06-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984;1530-6992; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.712 Times cited 33 Open Access
Notes European Union Seventh Framework Programme under Grant 312483 – ESTEEM; FWOl; esteem2_ta Approved Most recent IF: 12.712; 2014 IF: 13.592
Call Number UA @ lucian @ c:irua:118622 Serial 1075
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Author Khalilov, U.; Bogaerts, A.; Neyts, E.C.
Title Microscopic mechanisms of vertical graphene and carbon nanotube cap nucleation from hydrocarbon growth precursors Type A1 Journal article
Year 2014 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 6 Issue 15 Pages 9206-9214
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) Controlling and steering the growth of single walled carbon nanotubes is often believed to require controlling of the nucleation stage. Yet, little is known about the microscopic mechanisms governing the nucleation from hydrocarbon molecules. Specifically, we address here the dehydrogenation of hydrocarbon molecules and the formation of all-carbon graphitic islands on metallic nanoclusters from hydrocarbon molecules under conditions typical for carbon nanotube growth. Employing reactive molecular dynamics simulations, we demonstrate for the first time that the formation of a graphitic network occurs through the intermediate formation of vertically oriented, not fully dehydrogenated graphitic islands. Upon dehydrogenation of these vertical graphenes, the islands curve over the surface, thereby forming a carbon network covering the nanoparticle. The results indicate that controlling the extent of dehydrogenation offers an additional parameter to control the nucleation of carbon nanotubes.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000339861500103 Publication Date 2014-05-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 21 Open Access
Notes Approved Most recent IF: 7.367; 2014 IF: 7.394
Call Number UA @ lucian @ c:irua:117950 Serial 2027
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Author Khaletskaya, K.; Turner, S.; Tu, M.; Wannapaiboon, S.; Schneemann, A.; Meyer, R.; Ludwig, A.; Van Tendeloo, G.; Fischer, R.A.
Title Self-directed localization of ZIF-8 thin film formation by conversion of ZnO nanolayers Type A1 Journal article
Year 2014 Publication Advanced functional materials Abbreviated Journal Adv Funct Mater
Volume 24 Issue 30 Pages 4804-4811
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) Control of localized metal-organic framework (MOF) thin film formation is a challenge. Zeolitic imidazolate frameworks (ZIFs) are an important sub-class of MOFs based on transition metals and imidazolate linkers. Continuous coatings of intergrown ZIF crystals require high rates of heterogeneous nucleation. In this work, substrates coated with zinc oxide layers are used, obtained by atomic layer deposition (ALD) or by magnetron sputtering, to provide the Zn2+ ions required for nucleation and localized growth of ZIF-8 films ([Zn(mim)(2)]; Hmim = 2-methylimidazolate). The obtained ZIF-8 films reveal the expected microporosity, as deduced from methanol adsorption studies using an environmentally controlled quartz crystal microbalance (QCM) and comparison with bulk ZIF-8 reference data. The concept is transferable to other MOFs, and is applied to the formation of [Al(OH)(1,4-ndc)](n) (ndc = naphtalenedicarboxylate) thin films derived from Al2O3 nanolayers.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000340549900010 Publication Date 2014-05-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1616-301X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.124 Times cited 77 Open Access
Notes 312483 Esteem2; Fwo; esteem2_ta Approved Most recent IF: 12.124; 2014 IF: 11.805
Call Number UA @ lucian @ c:irua:119215 Serial 2975
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Author Zhang, Q.-Z.; Wang, Y.-N.; Bogaerts, A.
Title Heating mode transition in a hybrid direct current/dual-frequency capacitively coupled CF4 discharge Type A1 Journal article
Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 115 Issue 22 Pages 223302-223306
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) Computer simulations based on the particle-in-cell/Monte Carlo collision method are performed to study the plasma characteristics and especially the transition in electron heating mechanisms in a hybrid direct current (dc)/dual-frequency (DF) capacitively coupled CF 4 discharge. When applying a superposed dc voltage, the plasma density first increases, then decreases, and finally increases again, which is in good agreement with experiments. This trend can be explained by the transition between the four main heating modes, i.e., DF coupling, dc and DF coupling, dc source dominant heating, and secondary electron dominant heating.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000337891800006 Publication Date 2014-06-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 9 Open Access
Notes Approved Most recent IF: 2.068; 2014 IF: 2.183
Call Number UA @ lucian @ c:irua:117347 Serial 1414
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Author García-Sánchez, C.; Philips, D.A.; Gorlé, C.
Title Quantifying inflow uncertainties for CFD simulations of the flow in downtown Oklahoma City Type A1 Journal article
Year 2014 Publication Building and environment Abbreviated Journal Build Environ
Volume 78 Issue Pages 118-129
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) Computational Fluid Dynamics (CFD) methods are widely used to investigate wind flow and dispersion in urban environments. Validation with field experiments that represent the full complexity of the problem should be performed to assess the predictive capabilities of the computations. In this context it will be necessary to quantify the effect of uncertainties in simulations of the full-scale problem. The present study aims at quantifying the uncertainty related to the variability in the inflow boundary conditions for Reynolds-averaged Navier-Stokes (RANS) simulations of the flow in downtown Oklahoma City to address validation with the Joint Urban 2003 field measurements. Three uncertain inflow parameters were defined: the wind speed and wind direction at a reference height, and the aerodynamic roughness in the logarithmic velocity inlet profile. An ensemble of 729 RANS simulations were performed to determine the polynomial chaos expansion coefficients that define the response surfaces for the velocity magnitude and direction at 13 field measurement stations, and the results are compared to the experimental data. For the velocity magnitude the mean experimental velocity magnitude is encompassed within the 95% confidence interval for the magnitudes predicted by the Uncertainty Quantification study in all stations. For the velocity direction this holds in 11 out of 13 locations. The study demonstrates the significant potential of applying advanced uncertainty quantification methods to address validation with field measurements and to develop a more realistic approach to the definition of inflow boundary conditions in atmospheric CFD simulations. (C) 2014 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000338619700013 Publication Date 2014-05-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0360-1323; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.053 Times cited 29 Open Access
Notes Approved Most recent IF: 4.053; 2014 IF: 3.341
Call Number UA @ lucian @ c:irua:118632 Serial 2742
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Author Verreck, D.; Verhulst, A.S.; Sorée, B.; Collaert, N.; Mocuta, A.; Thean, A.; Groeseneken, G.
Title Improved source design for p-type tunnel field-effect transistors : towards truly complementary logic Type A1 Journal article
Year 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 105 Issue 24 Pages 243506
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Complementary logic based on tunnel field-effect transistors (TFETs) would drastically reduce power consumption thanks to the TFET's potential to obtain a sub-60 mV/dec subthreshold swing (SS). However, p-type TFETs typically do not meet the performance of n-TFETs for direct bandgap III-V configurations. The p-TFET SS stays well above 60 mV/dec, due to the low density of states in the conduction band. We therefore propose a source configuration in which a highly doped region is maintained only near the tunnel junction. In the remaining part of the source, the hot carriers in the exponential tail of the Fermi-Dirac distribution are blocked by reducing the doping degeneracy, either with a source section with a lower doping concentration or with a heterostructure. We apply this concept to n-p-i-p configurations consisting of In0.53Ga0.47As and an InP-InAs heterostructure. 15-band quantum mechanical simulations predict that the configurations with our source design can obtain sub-60 mV/dec SS, with an on-current comparable to the conventional source design. (C) 2014 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000346643600076 Publication Date 2014-12-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951;1077-3118; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 10 Open Access
Notes ; D. Verreck acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by imec's Industrial Affiliation Program. ; Approved Most recent IF: 3.411; 2014 IF: 3.302
Call Number UA @ lucian @ c:irua:122798 Serial 1568
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Author Monico, L.; Janssens, K.; Hendriks, E.; Brunetti, B.G.; Miliani, C.
Title Raman study of different crystalline forms of PbCrO4 and PbCr1-xSxO4 solid solutions for the noninvasive identification of chrome yellows in paintings : a focus on works by Vincent van Gogh Type A1 Journal article
Year 2014 Publication Journal of Raman spectroscopy Abbreviated Journal J Raman Spectrosc
Volume 45 Issue 11-12 Pages 1034-1045
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) Chrome yellows, a class of pigments frequently used by painters of the Impressionism and Post-impressionism period, are known for their different chemical stability; the latter depends on the chemical composition (PbCrO4, PbCr1-xSxO4) and crystalline structure (monoclinic or orthorhombic) of the material. The possibility to distinguish among different forms of this pigment is therefore relevant in order to extend knowledge on the corresponding degradation process that is observed on several original paintings. For this purpose, three paintings conserved at the Van Gogh Museum (Amsterdam) were analyzed using noninvasive Raman spectroscopy, while equivalent investigations employing bench-top instrumentation were performed to obtain information from micro-samples originating from these works of art. In each painting, the chrome yellow was identified either as monoclinic PbCrO4 or in the form of monoclinic PbCr1-xSxO4 (x<0.25) or S-rich orthorhombic PbCr1-xSxO4 (x similar to 0.5). Our ability to make this fairly subtle distinction is based on a Raman study of several oil paint model samples made up of monoclinic and/or orthorhombic crystalline forms of PbCrO4 and PbCr1-xSxO4 (0.1x0.8). These paints were studied using several excitation wavelengths (namely 785.0, 532.0, 514.5, and 488nm). Because of the absence of the resonance Raman effect, which strongly enhances the chromate symmetric stretching band, and the absence of any laser-induced photodecomposition, it is advantageous to acquire data at 785.0nm. The band-shape and the position of the chromate bending modes proved to be more sensitive to the solid solution composition and crystalline structure than the stretching modes and can be used as distinctive spectral markers to discriminate among the different chrome yellow forms that are present. Copyright (c) 2014 John Wiley & Sons, Ltd.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000346912700008 Publication Date 2014-07-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0377-0486 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.969 Times cited 34 Open Access
Notes ; This research was supported by Interuniversity Attraction Poles Programme – Belgian Science Policy (S2-ART project S4DA) and also presents results from GOA 'XANES meets ELNES' (Research Fund University of Antwerp, Belgium), FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. Support from the Italian projects PRIN (SICH Sustainability in Cultural Heritage: from diagnosis to the development of innovative system for consolidation, cleaning and protection) and PON (ITACHA Italian advanced technologies for cultural heritage applications) is also acknowledged. The analysis of the paintings Sunflowers gone to seed, Bank of the Seine, and Portrait of Gauguin was performed within the mobile laboratory access activity of the FP7 programme CHARISMA supported by EC (Grant Agreement 228330). LM acknowledges the Italian National Research Council (CNR) for the financial support in the framework of the Short Term Mobility Programme 2013. Thanks are expressed to Muriel Geldof, Cultural Heritage Agency of The Netherlands, for selecting and sharing the information on the cross-sections and to the staff of the Van Gogh Museum for the agreeable cooperation. ; Approved Most recent IF: 2.969; 2014 IF: 2.671
Call Number UA @ admin @ c:irua:122841 Serial 5798
Permanent link to this record
 
 
Author Chen, Y.; Shanenko, A.A.; Peeters, F.M.
Title Vortex anomaly in low-dimensional fermionic condensates : quantum confinement breaks chirality Type A1 Journal article
Year 2014 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 89 Issue 5 Pages 054513-54515
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Chiral fermions are responsible for low-temperature properties of vortices in fermionic condensates, both superconducting (charged) and superfluid (neutral). One of the most striking consequences of this fact is that the core of a single-quantum vortex collapses at low temperatures, T -> 0 (i.e., the Kramer-Pesch effect for superconductors), due to the presence of chiral quasiparticles in the vortex-core region. We show that the situation changes drastically for fermionic condensates confined in quasi-one-dimensional and quasi-two-dimensional geometries. Here quantum confinement breaks the chirality of in-core fermions. As a result, instead of the ultimate shrinking, the core of a single-quantum vortex extends at low temperatures, and the condensate profile surprisingly mimics the multiquantum vortex behavior. Our findings are relevant for nanoscale superconductors, such as recent metallic nanoislands on silicon, and also for ultracold superfluid Fermi gases in cigar-shaped and pancake-shaped atomic traps.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000332396800005 Publication Date 2014-02-19
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 5 Open Access
Notes ; This work was supported by the “Odysseus” Program of the Flemish Government, the Flemish Science Foundation (FWO-Vl), the Methusalem Program, and the National Science Foundation of China under Grant No. NSFC-11304134. A. A. S. acknowledges the support of Brazilian agencies CNPq and FACEPE (Grant No. APQ-0589-1.05/08). ; Approved Most recent IF: 3.836; 2014 IF: 3.736
Call Number UA @ lucian @ c:irua:115822 Serial 3850
Permanent link to this record
 
 
Author Maistrenko, Y.L.; Vasylenko, A.; Sudakov, O.; Levchenko, R.; Maistrenko, V.L.
Title Cascades of multiheaded chimera states for coupled phase oscillators Type A1 Journal article
Year 2014 Publication International journal of bifurcation and chaos in applied sciences and engineering Abbreviated Journal Int J Bifurcat Chaos
Volume 24 Issue 8 Pages 1440014
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) Chimera state is a recently discovered dynamical phenomenon in arrays of nonlocally coupled oscillators, that displays a self-organized spatial pattern of coexisting coherence and incoherence. We discuss the appearance of the chimera states in networks of phase oscillators with attractive and with repulsive interactions, i.e. when the coupling respectively favors synchronization or works against it. By systematically analyzing the dependence of the spatiotemporal dynamics on the level of coupling attractivity/repulsivity and the range of coupling, we uncover that different types of chimera states exist in wide domains of the parameter space as cascades of the states with increasing number of intervals of irregularity, so-called chimera's heads. We report three scenarios for the chimera birth: (1) via saddle-node bifurcation on a resonant invariant circle, also known as SNIC or SNIPER, (2) via blue-sky catastrophe, when two periodic orbits, stable and saddle, approach each other creating a saddle-node periodic orbit, and (3) via homoclinic transition with complex multistable dynamics including an “eight-like” limit cycle resulting eventually in a chimera state.
Address
Corporate Author Thesis
Publisher Place of Publication Singapore Editor
Language Wos 000341494900015 Publication Date 2014-08-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0218-1274;1793-6551; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.329 Times cited Open Access
Notes Approved Most recent IF: 1.329; 2014 IF: 1.078
Call Number UA @ lucian @ c:irua:119303 Serial 285
Permanent link to this record
 
 
Author Anaf, W.; Trashin, S.; Schalm, O.; van Dorp, D.; Janssens, K.; De Wael, K.
Title Electrochemical photodegradation study of semiconductor pigments : influence of environmental parameters Type A1 Journal article
Year 2014 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 86 Issue 19 Pages 9742-9748
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
Abstract (down) Chemical transformations in paintings often induce discolorations, disturbing the appearance of the image. For an appropriate conservation of such valuable and irreplaceable heritage objects, it is important to have a good know-how on the degradation processes of the (historical) materials: which pigments have been discolored, what are the responsible processes, and which (environmental) conditions have the highest impact on the pigment degradation and should be mitigated. Pigment degradation is already widely studied, either by analyzing historical samples or by accelerated weathering experiments on dummies. However, in historic samples several processes may have taken place, increasing the complexity of the current state, while aging experiments are time-consuming due to the often extended aging period. An alternative method is proposed for a fast monitoring of degradation processes of semiconductor pigments, using an electrochemical setup mimicking the real environment and allowing the identification of harmful environmental parameters for each pigment. Examples are given for the pigments cadmium yellow (CdS) and vermilion (α-HgS).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000343017100058 Publication Date 2014-08-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 18 Open Access
Notes ; ; Approved Most recent IF: 6.32; 2014 IF: 5.636
Call Number UA @ admin @ c:irua:118834 Serial 5593
Permanent link to this record
 
 
Author Tian, H.; Verbeeck, J.; Brück, S.; Paul, M.; Kufer, D.; Sing, M.; Claessen, R.; Van Tendeloo, G.
Title Interface-induced modulation of charge and polarization in thin film Fe3O4 Type A1 Journal article
Year 2014 Publication Advanced materials Abbreviated Journal Adv Mater
Volume 26 Issue 3 Pages 461-465
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) Charge and polarization modulations in Fe3O4 are controlled by taking advantage of interfacial strain effects. The feasibility of oxidation state control by strain modification is demonstrated and it is shown that this approach offers a stable configuration at room temperature. Direct evidence of how a local strain field changes the atomic coordination and introduces atomic displacements leading to polarization of Fe ions is presented.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000334289300011 Publication Date 2013-10-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 19.791 Times cited 15 Open Access
Notes Vortex; FWO; Countatoms; Hercules ECASJO_; Approved Most recent IF: 19.791; 2014 IF: 17.493
Call Number UA @ lucian @ c:irua:112419UA @ admin @ c:irua:112419 Serial 1694
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Author Çakir, D.; Otalvaro, D.M.; Brocks, G.
Title Magnetoresistance in multilayer fullerene spin valves: A first-principles study Type A1 Journal article
Year 2014 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 90 Issue 24 Pages 245404
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Carbon-based molecular semiconductors are explored for application in spintronics because their small spinorbit coupling promises long spin lifetimes. We calculate the electronic transport from first principles through spin valves comprising bi-and tri-layers of the fullerene molecules C-60 and C-70, sandwiched between two Fe electrodes. The spin polarization of the current, and the magnetoresistance depend sensitively on the interactions at the interfaces between the molecules and the metal surfaces. They are much less affected by the thickness of the molecular layers. A high current polarization (CP > 90%) and magnetoresistance (MR > 100%) at small bias can be attained using C-70 layers. In contrast, the current polarization and the magnetoresistance at small bias are vanishingly small for C-60 layers. Exploiting a generalized Julliere model we can trace the differences in spin-dependent transport between C-60 and C-70 layers to differences between the molecule-metal interface states. These states also allow one to interpret the current polarization and the magnetoresistance as a function of the applied bias voltage.
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Publisher Place of Publication Editor
Language Wos 000345875200005 Publication Date 2014-12-02
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 ; ; Approved Most recent IF: 3.836; 2014 IF: 3.736
Call Number UA @ lucian @ c:irua:122177 Serial 1928
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