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Author Bekaert, J.; Saniz, R.; Partoens, B.; Lamoen, D.
  Title First-principles study of carbon impurities in CuInSe2 and CuGaSe2, present in non-vacuum synthesis methods Type A1 Journal article
  Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 117 Issue 117 Pages 015104
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
  Abstract A first-principles study of the structural and electronic properties of carbon impurities in CuInSe2 and CuGaSe2 is presented. Carbon is present in organic molecules in the precursor solutions used in non-vacuum growth methods for CuInSe2 and CuGaSe2 based photovoltaic cells. These growth methods make more efficient use of material, time, and energy than traditional vacuum methods. The formation energies of several carbon impurities are calculated using the hybrid HSE06 functional. C Cu acts as a shallow donor, CIn and interstitial C yield deep donor levels in CuInSe2, while in CuGaSe2 CGa and interstitial C act as deep amphoteric defects. So, these defects reduce the majority carrier (hole) concentration in p-type CuInSe2 and CuGaSe2 by compensating the acceptor levels. The deep defects are likely to act as recombination centers for the photogenerated charge carriers and are thus detrimental for the performance of the photovoltaic cells. On the other hand, the formation energies of the carbon impurities are high, even under C-rich growth conditions. Thus, few C impurities will form in CuInSe2 and CuGaSe2 in thermodynamic equilibrium. However, the deposition of the precursor solution in non-vacuum growth methods presents conditions far from thermodynamic equilibrium. In this case, our calculations show that C impurities formed in non-equilibrium tend to segregate from CuInSe2 and CuGaSe2 by approaching thermodynamic equilibrium, e.g., via thorough annealing.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000347958600055 Publication Date 2015-01-07
  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 6 Open Access
  Notes FWO G015013; Hercules Approved Most recent IF: 2.068; 2015 IF: 2.183
  Call Number c:irua:122064 Serial 1215
Permanent link to this record
 

 
Author Kelchtermans, A.; Adriaensens, P.; Slocombe, D.; Kuznetsov, V.L.; Hadermann, J.; Riskin, A.; Elen, K.; Edwards, P.P.; Hardy, A.; Van Bael, M.K.
  Title Increasing the solubility limit for tetrahedral aluminium in ZnO:Al nanorods by variation in synthesis parameters Type A1 Journal article
  Year 2015 Publication Journal of nanomaterials Abbreviated Journal J Nanomater
  Volume 2015 Issue 2015 Pages 1-8
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Nanocrystalline ZnO:Al nanoparticles are suitable building blocks for transparent conductive layers. As the concentration of substitutional tetrahedral Al is an important factor for improving conductivity, here we aim to increase the fraction of substitutional Al. To this end, synthesis parameters of a solvothermal reaction yielding ZnO:Al nanorods were varied. A unique set of complementary techniques was combined to reveal the exact position of the aluminium ions in the ZnO lattice and demonstrated its importance in order to evaluate the potential of ZnO:Al nanocrystals as optimal building blocks for solution deposited transparent conductive oxide layers. Both an extension of the solvothermal reaction time and stirring during solvothermal treatment result in a higher total tetrahedral aluminium content in the ZnO lattice. However, only the longer solvothermal treatment effectively results in an increase of the substitutional positions aimed for.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) New York, N.Y. Editor
  Language Wos 000358516300001 Publication Date 2015-07-12
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1687-4110;1687-4129; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.871 Times cited 2 Open Access
  Notes FWO; Methusalem Approved Most recent IF: 1.871; 2015 IF: 1.644
  Call Number c:irua:124426 Serial 1600
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Author Dumpala, S.; Broderick, S.R.; Khalilov, U.; Neyts, E.C.; van Duin, A.C.T.; Provine, J.; Howe, R.T.; Rajan, K.
  Title Integrated atomistic chemical imaging and reactive force field molecular dynamic simulations on silicon oxidation Type A1 Journal article
  Year 2015 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 106 Issue 106 Pages 011602
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract In this paper, we quantitatively investigate with atom probe tomography, the effect of temperature on the interfacial transition layer suboxide species due to the thermal oxidation of silicon. The chemistry at the interface was measured with atomic scale resolution, and the changes in chemistry and intermixing at the interface were identified on a nanometer scale. We find an increase of suboxide (SiOx) concentration relative to SiO2 and increased oxygen ingress with elevated temperatures. Our experimental findings are in agreement with reactive force field molecular dynamics simulations. This work demonstrates the direct comparison between atom probe derived chemical profiles and atomistic-scale simulations for transitional interfacial layer of suboxides as a function of temperature.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000347976900008 Publication Date 2015-01-06
  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 19 Open Access
  Notes Approved Most recent IF: 3.411; 2015 IF: 3.302
  Call Number c:irua:122300 Serial 1679
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Author Zhang, Y.-R.; Tinck, S.; De Schepper, P.; Wang, Y.-N.; Bogaerts, A.
  Title Modeling and experimental investigation of the plasma uniformity in CF4/O2 capacitively coupled plasmas, operating in single frequency and dual frequency regime Type A1 Journal article
  Year 2015 Publication Journal of vacuum science and technology: A: vacuum surfaces and films Abbreviated Journal J Vac Sci Technol A
  Volume 33 Issue 33 Pages 021310
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract A two-dimensional hybrid Monte Carlofluid model, incorporating a full-wave solution of Maxwell's equations, is employed to describe the behavior of high frequency (HF) and very high frequency capacitively coupled plasmas (CCPs), operating both at single frequency (SF) and dual frequency (DF) in a CF4/O2 gas mixture. First, the authors investigate the plasma composition, and the simulations reveal that besides CF4 and O2, also COF2, CF3, and CO2 are important neutral species, and CF+3 and F− are the most important positive and negative ions. Second, by comparing the results of the model with and without taking into account the electromagnetic effects for a SF CCP, it is clear that the electromagnetic effects are important, both at 27 and 60 MHz, because they affect the absolute values of the calculation results and also (to some extent) the spatial profiles, which accordingly affects the uniformity in plasma processing. In order to improve the plasma radial uniformity, which is important for the etch process, a low frequency (LF) source is added to the discharge. Therefore, in the major part of the paper, the plasma uniformity is investigated for both SF and DF CCPs, operating at a HF of 27 and 60 MHz and a LF of 2 MHz. For this purpose, the authors measure the etch rates as a function of position on the wafer in a wide range of LF powers, and the authors compare them with the calculated fluxes toward the wafer of the plasma species playing a role in the etch process, to explain the trends in the measured etch rate profiles. It is found that at a HF of 60 MHz, the uniformity of the etch rate is effectively improved by adding a LF power of 2 MHz and 300 W, while its absolute value increases by about 50%, thus a high etch rate with a uniform distribution is observed under this condition.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) New York, N.Y. Editor
  Language Wos 000355739500026 Publication Date 2015-01-29
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0734-2101;1520-8559; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.374 Times cited 3 Open Access
  Notes Approved Most recent IF: 1.374; 2015 IF: 2.322
  Call Number c:irua:122650 Serial 2107
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Author Li, L.L.; Xu, W.; Peeters, F.M.
  Title Optical conductivity of topological insulator thin films Type A1 Journal article
  Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 117 Issue 117 Pages 175305
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We present a detailed theoretical study on the optoelectronic properties of topological insulator thin film (TITFs). The k . p approach is employed to calculate the energy spectra and wave functions for both the bulk and surface states in the TITF. With these obtained results, the optical conductivities induced by different electronic transitions among the bulk and surface states are evaluated using the energy-balance equation derived from the Boltzmann equation. We find that for Bi2Se3-based TITFs, three characteristic regimes for the optical absorption can be observed. (i) In the low radiation frequency regime (photon energy (h) over bar omega < 200 meV), the free-carrier absorption takes place due to intraband electronic transitions. An optical absorption window can be observed. (ii) In the intermediate radiation frequency regime (200 < (h) over bar omega < 300 meV), the optical absorption is induced mainly by interband electronic transitions from surface states in the valance band to surface states in the conduction band and an universal value sigma(0) = e(2) / (8<(h)over bar>) for the optical conductivity can be obtained. (iii) In the high radiation frequency regime ((h) over bar omega > 300 meV), the optical absorption can be achieved via interband electronic transitions from bulk and surface states in the valance band to bulk and surface states in the conduction band. A strong absorption peak can be observed. These interesting findings indicate that optical measurements can be applied to identify the energy regimes of bulk and surface states in the TITF. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000354984100615 Publication Date 2015-05-06
  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 ; This work was supported by the National Natural Science Foundation of China (Grant No. 11304316), Ministry of Science and Technology of China (Grant No. 2011YQ130018), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. ; Approved Most recent IF: 2.068; 2015 IF: 2.183
  Call Number c:irua:126412 Serial 2473
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Author Garcia, J.H.; Covaci, L.; Rappoport, T.G.
  Title Real-space calculation of the conductivity tensor for disordered topological matter Type A1 Journal article
  Year 2015 Publication Physical review letters Abbreviated Journal Phys Rev Lett
  Volume 114 Issue 114 Pages 116602
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We describe an efficient numerical approach to calculate the longitudinal and transverse Kubo conductivities of large systems using Bastin's formulation. We expand the Green's functions in terms of Chebyshev polynomials and compute the conductivity tensor for any temperature and chemical potential in a single step. To illustrate the power and generality of the approach, we calculate the conductivity tensor for the quantum Hall effect in disordered graphene and analyze the effect of the disorder in a Chern insulator in Haldane's model on a honeycomb lattice.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) New York, N.Y. Editor
  Language Wos 000351430600010 Publication Date 2015-03-20
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 8.462 Times cited 69 Open Access
  Notes ; We acknowledge A. R. Hernandez, A. Ferreira, and E. Mucciolo for discussions. T. G. R and J. H. G acknowledge the Brazilian agencies CNPq, FAPERJ, and INCT de Nanoestruturas de Carbono for financial support. L. C. acknowledges the Flemish Science Foundation (FWO-Vlaanderen) for financial support. ; Approved Most recent IF: 8.462; 2015 IF: 7.512
  Call Number c:irua:125467 Serial 2827
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Author McCalla, E.; Prakash, A.S.; Berg, E.; Saubanere, M.; Abakumov, A.M.; Foix, D.; Klobes, B.; Sougrati, M.T.; Rousse, G.; Lepoivre, F.; Mariyappan, S.; Doublet, M.L.; Gonbeau, D.; Novak, P.; Van Tendeloo, G.; Hermann, R.P.; Tarascon, J.M.;
  Title Reversible Li-intercalation through oxygen reactivity in Li-rich Li-Fe-Te oxide materials Type A1 Journal article
  Year 2015 Publication Journal of the electrochemical society Abbreviated Journal J Electrochem Soc
  Volume 162 Issue 162 Pages A1341-A1351
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Lithium-rich oxides are a promising class of positive electrode materials for next generation lithium-ion batteries, and oxygen plays a prominent role during electrochemical cycling either by forming peroxo-like species and/or by irreversibly forming oxygen gas during first charge. Here, we present Li-Fe-Te-O materials which show a tremendous amount of oxygen gas release. This oxygen release accounts for nearly all the capacity during the first charge and results in vacancies as seen by transmission electron microscopy. There is no oxidation of either metal during charge but significant changes in their environments. These changes are particularly extreme for tellurium. XRD and neutron powder diffraction both show limited Changes during cycling and no appreciable change in lattice parameters. A density functional theory study of this material is performed and demonstrates that the holes created on some of the oxygen atoms upon oxidation are partially stabilized through the formation of shorter O-O bonds, i.e. (O-2)(n-) species which on further delithiation show a spontaneous O-2 de-coordination from the cationic network and migration to the now empty lithium layer. The rate limiting step during charge is undoubtedly the diffusion of oxygen either out along the lithium layer or via columns of oxygen atoms. (C) 2015 The Electrochemical Society. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) New York, N.Y. Editor
  Language Wos 000355643700030 Publication Date 2015-04-29
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0013-4651;1945-7111; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.259 Times cited 23 Open Access
  Notes Approved Most recent IF: 3.259; 2015 IF: 3.266
  Call Number c:irua:126445 Serial 2903
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Author Torun, E.; Sahin, H.; Singh, S.K.; Peeters, F.M.
  Title Stable half-metallic monolayers of FeCl2 Type A1 Journal article
  Year 2015 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 106 Issue 106 Pages 192404
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The structural, electronic, and magnetic properties of single layers of Iron Dichloride (FeCl2) were calculated using first principles calculations. We found that the 1T phase of the single layer FeCl2 is 0.17 eV/unit cell more favorable than its 1H phase. The structural stability is confirmed by phonon calculations. We found that 1T-FeCl2 possess three Raman-active (130, 179, and 237 cm(-1)) and one infrared-active (279 cm(-1)) phonon branches. The electronic band dispersion of the 1T-FeCl2 is calculated using both gradient approximation of Perdew-Burke-Ernzerhof and DFT-HSE06 functionals. Both functionals reveal that the 1T-FeCl2 has a half-metallic ground state with a Curie temperature of 17 K. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000355008100020 Publication Date 2015-05-13
  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 84 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. was supported by a FWO Pegasus Long Marie Curie Fellowship. ; Approved Most recent IF: 3.411; 2015 IF: 3.302
  Call Number c:irua:126411 Serial 3143
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Author Euan-Diaz, E.; Herrera-Velarde, S.; Misko, V.R.; Peeters, F.M.; Castaneda-Priego, R.
  Title Structural transitions and long-time self-diffusion of interacting colloids confined by a parabolic potential Type A1 Journal article
  Year 2015 Publication The journal of chemical physics Abbreviated Journal J Chem Phys
  Volume 142 Issue 142 Pages 024902
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We report on the ordering and dynamics of interacting colloidal particles confined by a parabolic potential. By means of Brownian dynamics simulations, we find that by varying the magnitude of the trap stiffness, it is possible to control the dimension of the system and, thus, explore both the structural transitions and the long-time self-diffusion coefficient as a function of the degree of confinement. We particularly study the structural ordering in the directions perpendicular and parallel to the confinement. Further analysis of the local distribution of the first-neighbors layer allows us to identify the different structural phases induced by the parabolic potential. These results are summarized in a structural state diagram that describes the way in which the colloidal suspension undergoes a structural re-ordering while increasing the confinement. To fully understand the particle dynamics, we take into account hydrodynamic interactions between colloids; the parabolic potential constricts the available space for the colloids, but it does not act on the solvent. Our findings show a non-linear behavior of the long-time self-diffusion coefficient that is associated to the structural transitions induced by the external field. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) New York, N.Y. Editor
  Language Wos 000348129700053 Publication Date 2015-01-10
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0021-9606;1089-7690; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.965 Times cited 7 Open Access
  Notes ; This work was partially supported by the “Odysseus” Program of the Flemish Government, the Flemish Science Foundation (FWO-Vl), PIFI 3.4 – PROMEP, and CONACyT (Grant Nos. 61418/2007, 102339/2008, Ph.D. scholarship 230171/2010). R.C.-P. also acknowledges financial support provided by the Marcos Moshinsky fellowship 2013-2014. The authors also thank to the General Coordination of Information and Communications Technologies (CGSTIC) at Cinvestav for providing HPC resources on the Hybrid Cluster Super-computer Xiuhcoatl, which have contributed partially to the research results reported in this paper. ; Approved Most recent IF: 2.965; 2015 IF: 2.952
  Call Number c:irua:123832 Serial 3267
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Author Zhao, C.X.; Xu, W.; Li, L.L.; Zhang, C.; Peeters, F.M.
  Title Terahertz plasmon-polariton modes in graphene driven by electric field inside a Fabry-Perot cavity Type A1 Journal article
  Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 117 Issue 117 Pages 223104
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We present a theoretical study on plasmon-polariton modes in graphene placed inside an optical cavity and driven by a source-to-drain electric field. The electron velocity and electron temperature are determined by solving self-consistently the momentum-and energy-balance equations in which electron interactions with impurities, acoustic-, and optic-phonons are included. Based on many-body self-consistent field theory, we develop a tractable approach to study plasmon-polariton in an electron gas system. We find that when graphene is placed inside a Fabry-Perot cavity, two branches of the plasmon-polariton modes can be observed and these modes are very much optic-or plasmon-like. The frequencies of these modes depend markedly on driving electric field especially at higher resonant frequency regime. Moreover, the plasmon-polariton frequency in graphene is in terahertz (THz) bandwidth and can be tuned by changing the cavity length, gate voltage, and driving electric field. This work is pertinent to the application of graphene-based structures as tunable THz plasmonic devices. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000356176100004 Publication Date 2015-06-10
  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 13 Open Access
  Notes ; This work was supported by the Ministry of Science and Technology of China (Grant No. 2011YQ130018), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. F.M.P. was a specially appointed Professor for foreign expert at the Chinese Academy of Sciences. ; Approved Most recent IF: 2.068; 2015 IF: 2.183
  Call Number c:irua:127076 Serial 3507
Permanent link to this record
 

 
Author Berdiyorov, G.R.; Bahlouli, H.; Peeters, F.M.
  Title Theoretical study of electronic transport properties of a graphene-silicene bilayer Type A1 Journal article
  Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 117 Issue 117 Pages 225101
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Electronic transport properties of a graphene-silicene bilayer system are studied using density-functional theory in combination with the nonequilibrium Green's function formalism. Depending on the energy of the electrons, the transmission can be larger in this system as compared to the sum of the transmissions of separated graphene and silicene monolayers. This effect is related to the increased electron density of states in the bilayer sample. At some energies, the electronic states become localized in one of the layers, resulting in the suppression of the electron transmission. The effect of an applied voltage on the transmission becomes more pronounced in the layered sample as compared to graphene due to the larger variation of the electrostatic potential profile. Our findings will be useful when creating hybrid nanoscale devices where enhanced transport properties will be desirable. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000356176100040 Publication Date 2015-06-10
  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 10 Open Access
  Notes ; H. B. and F. M. P. acknowledge support from King Fahd University of Petroleum and Minerals, Saudi Arabia, under the RG1329-1 and RG1329-2 DSR Projects. ; Approved Most recent IF: 2.068; 2015 IF: 2.183
  Call Number c:irua:127075 Serial 3611
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Author Homm, P.; Dillemans, L.; Menghini, M.; Van Bilzen, B.; Bakalov, P.; Su, C.Y.; Lieten, R.; Houssa, M.; Nasr Esfahani, D.; Covaci, L.; Peeters, F.M.; Seo, J.W.; Locquet, J.P.;
  Title Collapse of the low temperature insulating state in Cr-doped V2O3 thin films Type A1 Journal article
  Year 2015 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 107 Issue 107 Pages 111904
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We have grown epitaxial Cr-doped V2O3 thin films with Cr concentrations between 0% and 20% on (0001)-Al2O3 by oxygen-assisted molecular beam epitaxy. For the highly doped samples (>3%), a regular and monotonous increase of the resistance with decreasing temperature is measured. Strikingly, in the low doping samples (between 1% and 3%), a collapse of the insulating state is observed with a reduction of the low temperature resistivity by up to 5 orders of magnitude. A vacuum annealing at high temperature of the films recovers the low temperature insulating state for doping levels below 3% and increases the room temperature resistivity towards the values of Cr-doped V2O3 single crystals. It is well-know that oxygen excess stabilizes a metallic state in V2O3 single crystals. Hence, we propose that Cr doping promotes oxygen excess in our films during deposition, leading to the collapse of the low temperature insulating state at low Cr concentrations. These results suggest that slightly Cr-doped V2O3 films can be interesting candidates for field effect devices. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000361639200020 Publication Date 2015-09-19
  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 14 Open Access
  Notes ; The authors acknowledge financial support from the FWO Project No. G052010N10 as well as the EU-FP7 SITOGA Project. P.H. acknowledges support from Becas Chile-CONICYT. ; Approved Most recent IF: 3.411; 2015 IF: 3.302
  Call Number UA @ lucian @ c:irua:128728 Serial 4149
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Author Verreck, D.; Verhulst, A.S.; Van de Put, M.; Sorée, B.; Magnus, W.; Mocuta, A.; Collaert, N.; Thean, A.; Groeseneken, G.
  Title Full-zone spectral envelope function formalism for the optimization of line and point tunnel field-effect transistors Type A1 Journal article
  Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 118 Issue 118 Pages 134502
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Efficient quantum mechanical simulation of tunnel field-effect transistors (TFETs) is indispensable to allow for an optimal configuration identification. We therefore present a full-zone 15-band quantum mechanical solver based on the envelope function formalism and employing a spectral method to reduce computational complexity and handle spurious solutions. We demonstrate the versatility of the solver by simulating a 40 nm wide In0.53Ga0.47As lineTFET and comparing it to p-n-i-n configurations with various pocket and body thicknesses. We find that the lineTFET performance is not degraded compared to semi-classical simulations. Furthermore, we show that a suitably optimized p-n-i-n TFET can obtain similar performance to the lineTFET. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000362668400025 Publication Date 2015-10-01
  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 ; 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: 2.068; 2015 IF: 2.183
  Call Number UA @ lucian @ c:irua:128765 Serial 4183
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Author Moors, K.; Sorée, B.; Magnus, W.
  Title Modeling surface roughness scattering in metallic nanowires Type A1 Journal article
  Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 118 Issue 118 Pages 124307
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Ando's model provides a rigorous quantum-mechanical framework for electron-surface roughness scattering, based on the detailed roughness structure. We apply this method to metallic nanowires and improve the model introducing surface roughness distribution functions on a finite domain with analytical expressions for the average surface roughness matrix elements. This approach is valid for any roughness size and extends beyond the commonly used Prange-Nee approximation. The resistivity scaling is obtained from the self-consistent relaxation time solution of the Boltzmann transport equation and is compared to Prange-Nee's approach and other known methods. The results show that a substantial drop in resistivity can be obtained for certain diameters by achieving a large momentum gap between Fermi level states with positive and negative momentum in the transport direction. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000362565800032 Publication Date 2015-09-24
  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 11 Open Access
  Notes ; ; Approved Most recent IF: 2.068; 2015 IF: 2.183
  Call Number UA @ lucian @ c:irua:129425 Serial 4207
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Author Yagmurcukardes, M.; Sahin, H.; Kang, J.; Torun, E.; Peeters, F.M.; Senger, R.T.
  Title Pentagonal monolayer crystals of carbon, boron nitride, and silver azide Type A1 Journal article
  Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 118 Issue 118 Pages 104303
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract In this study, we present a theoretical investigation of structural, electronic, and mechanical properties of pentagonal monolayers of carbon (p-graphene), boron nitride (p-B2N4 and p-B4N2), and silver azide (p-AgN3) by performing state-of-the-art first principles calculations. Our total energy calculations suggest feasible formation of monolayer crystal structures composed entirely of pentagons. In addition, electronic band dispersion calculations indicate that while p-graphene and p-AgN3 are semiconductors with indirect bandgaps, p-BN structures display metallic behavior. We also investigate the mechanical properties (in-plane stiffness and the Poisson's ratio) of four different pentagonal structures under uniaxial strain. p-graphene is found to have the highest stiffness value and the corresponding Poisson's ratio is found to be negative. Similarly, p-B2N4 and p-B4N2 have negative Poisson's ratio values. On the other hand, the p-AgN3 has a large and positive Poisson's ratio. In dynamical stability tests based on calculated phonon spectra of these pentagonal monolayers, we find that only p-graphene and p-B2N4 are stable, but p-AgN3 and p-B4N2 are vulnerable against vibrational excitations.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000361636900028 Publication Date 2015-09-08
  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 79 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). H.S. was supported by a FWO Pegasus Long Marie Curie Fellowship. H.S. and R.T.S. acknowledge the support from TUBITAK through Project No. 114F397. ; Approved Most recent IF: 2.068; 2015 IF: 2.183
  Call Number UA @ lucian @ c:irua:128415 Serial 4223
Permanent link to this record
 

 
Author de Sousa, A.A.; Chaves, A.; Pereira, T.A.S.; Farias, G.A.; Peeters, F.M.
  Title Quantum tunneling between bent semiconductor nanowires Type A1 Journal article
  Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 118 Issue 118 Pages 174301
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We theoretically investigate the electronic transport properties of two closely spaced L-shaped semiconductor quantum wires, for different configurations of the output channel widths as well as the distance between the wires. Within the effective-mass approximation, we solve the time-dependent Schrodinger equation using the split-operator technique that allows us to calculate the transmission probability, the total probability current, the conductance, and the wave function scattering between the energy subbands. We determine the maximum distance between the quantum wires below which a relevant non-zero transmission is still found. The transmission probability and the conductance show a strong dependence on the width of the output channel for small distances between the wires. (C) 2015 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor
  Language Wos 000364584200020 Publication Date 2015-11-02
  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 7 Open Access
  Notes ; A. A. Sousa was financially supported by CAPES, under the PDSE Contract No. BEX 7177/13-5. T. A. S. Pereira was financially supported by PRONEX/CNPq/FAPEMAT 850109/2009 and by CAPES under process BEX 3299/13-9. This work was financially supported by PRONEX/CNPq/FUNCAP, the Science Without Borders program and the bilateral project CNPq-FWO. ; Approved Most recent IF: 2.068; 2015 IF: 2.183
  Call Number UA @ lucian @ c:irua:129544 Serial 4234
Permanent link to this record
 

 
Author Lu, Y.-G.; Turner, S.; Ekimov, E.A.; Verbeeck, J.; Van Tendeloo, G.
  Title Boron-rich inclusions and boron distribution in HPHT polycrystalline superconducting diamond Type A1 Journal article
  Year 2015 Publication Carbon Abbreviated Journal Carbon
  Volume 86 Issue 86 Pages 156-162
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Polycrystalline boron-doped superconducting diamond, synthesized at high pressure and high temperature (HPHT) via a reaction of a single piece of crystalline boron with monolithic graphite, has been investigated by analytical transmission electron microscopy. The local boron distribution and boron environment have been studied by a combination of (scanning) transmission electron microscopy ((S)TEM) and spatially resolved electron energy-loss spectroscopy (EELS). High resolution TEM imaging and EELS elemental mapping have established, for the first time, the presence of largely crystalline diamond-diamond grain boundaries within the material and have evidenced the presence of substitutional boron dopants within individual diamond grains. Confirmation of the presence of substitutional B dopants has been obtained through comparison of acquired boron K-edge EELS fine structures with known references. This confirmation is important to understand the origin of superconductivity in polycrystalline B-doped diamond. In addition to the substitutional boron doping, boron-rich inclusions and triple-points, both amorphous and crystalline, with chemical compositions close to boron carbide B4C, are evidenced. (C) 2015 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Oxford Editor
  Language Wos 000352922700019 Publication Date 2015-01-22
  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 20 Open Access
  Notes FWO; 246791 COUNTATOMS; 278510 VORTEX; Hercules ECASJO_; Approved Most recent IF: 6.337; 2015 IF: 6.196
  Call Number c:irua:125994UA @ admin @ c:irua:125994 Serial 250
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Author van Dyck, D.; Lobato, I.; Chen, F.-R.; Kisielowski, C.
  Title Do you believe that atoms stay in place when you observe them in HREM? Type A1 Journal article
  Year 2015 Publication Micron Abbreviated Journal Micron
  Volume 68 Issue 68 Pages 158-163
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
  Abstract Recent advancements in aberration-corrected electron microscopy allow for an evaluation of unexpectedly large atom displacements beyond a resolution limit of similar to 0.5 angstrom, which are found to be dose-rate dependent in high resolution images. In this paper we outline a consistent description of the electron scattering process, which explains these unexpected phenomena. Our approach links thermal diffuse scattering to electron beam-induced object excitation and relaxation processes, which strongly contribute to the image formation process. The effect can provide an explanation for the well-known contrast mismatch (“Stobbs factor”) between image calculations and experiments. (C) 2014 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Oxford Editor
  Language Wos 000348016500023 Publication Date 2014-09-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0968-4328; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.98 Times cited 11 Open Access
  Notes Approved Most recent IF: 1.98; 2015 IF: 1.988
  Call Number c:irua:123802 Serial 745
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Author Wang, X.; Kustov, S.; Li, K.; Schryvers, D.; Verlinden, B.; Van Humbeeck, J.
  Title Effect of nanoprecipitates on the transformation behavior and functional properties of a Ti50.8 at.% Ni alloy with micron-sized grains Type A1 Journal article
  Year 2015 Publication Acta materialia Abbreviated Journal Acta Mater
  Volume 82 Issue 82 Pages 224-233
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract In order to take advantage of both grain refinement and precipitation hardening effects, nanoscaled Ni4Ti3 precipitates are introduced in a Ti50.8 at.% Ni alloy with micron-sized grains (average grain size of 1.7 μm). Calorimetry, electrical resistance studies and thermomechanical tests were employed to study the transformation behavior and functional properties in relation to the obtained microstructure. A significant suppression of martensite transformation by the obtained microstructure is observed. The thermomechanical tests show that the advantageous properties of both grain refinement and precipitation hardening are combined in the developed materials, resulting in superior shape memory characteristics and stability of pseudoelasticity. It is concluded that introducing nanoscaled Ni4Ti3 precipitates into small grains is a new approach to improve the functional properties of NiTi shape memory alloys.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Oxford Editor
  Language Wos 000347017800021 Publication Date 2014-10-04
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1359-6454; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 5.301 Times cited 51 Open Access
  Notes Fwo Approved Most recent IF: 5.301; 2015 IF: 4.465
  Call Number c:irua:120469 Serial 824
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Author Delmelle, R.; Amin-Ahmadi, B.; Sinnaeve, M.; Idrissi, H.; Pardoen, T.; Schryvers, D.; Proost, J.
  Title Effect of structural defects on the hydriding kinetics of nanocrystalline Pd thin films Type A1 Journal article
  Year 2015 Publication International journal of hydrogen energy Abbreviated Journal Int J Hydrogen Energ
  Volume 40 Issue 40 Pages 7335-7347
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract While the microstructure of a metal is well-known to affect its equilibrium hydrogen uptake and therefore the hydriding thermodynamics, microstructural effects on the hydriding kinetics are much less documented. Moreover, for thin film systems, such microstructural effects are difficult to separate from the internal stress effect, since most defects generate internal stresses. Such a decoupling has been achieved in this paper for nanocrystalline Pd thin film model systems through the use of a high-resolution, in-situ curvature measurement set-up during Pd deposition, annealing and hydriding. This set-up allowed producing Pd thin films with similar internal stress levels but significantly different microstructures. This was evidenced from detailed defect statistics obtained by transmission electron microscopy, which showed that the densities of grain boundaries, dislocations and twin boundaries have all been lowered by annealing. The same set-up was then used to study the hydriding equilibrium and kinetic behaviour of the resulting films at room temperature. A full quantitative analysis of their hydriding cycles showed that the rate constants of both the adsorption- and absorption-limited kinetic regimes were strongly affected by microstructure. Defect engineering was thereby shown to increase the rate constants for hydrogen adsorption and absorption in Pd by a factor 40 and 30, respectively. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Oxford Editor
  Language Wos 000355884300012 Publication Date 2015-05-02
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0360-3199; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.582 Times cited 13 Open Access
  Notes Iap 7/21 Approved Most recent IF: 3.582; 2015 IF: 3.313
  Call Number c:irua:126429 Serial 838
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Author Kirilenko, D.A.; Dideykin, A.T.; Aleksenskiy, A.E.; Sitnikova, A.A.; Konnikov, S.G.; Vul', A.Y.
  Title One-step synthesis of a suspended ultrathin graphene oxide film: Application in transmission electron microscopy Type A1 Journal article
  Year 2015 Publication Micron Abbreviated Journal Micron
  Volume 68 Issue 68 Pages 23-26
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Ultrathin graphene films find their use as advantageous support for nano- and biomaterials investigations. Thin film causes a very slight deterioration to measured signals, thus providing more details of the object's structure at nanoscale. The ultimate thinness of graphene works in the best way for this purpose. However, obtaining suspended thin film of a large-area, which is convenient for applications, is often a relatively complicated and time-consuming task. Here we present a one-step 1-min technique for synthesis of an extremely thin (about 1-2 nm) continuous film suspended over cells of a conventional copper grid (50-400 mu m mesh). This technique enables us to acquire a large-area film which is water-resistant, stable in organic solvents and can act as a support when studying nanoparticles or biomaterials. Moreover, the very mechanism of the film formation can be interesting from the point of view of other applications of ultrathin graphene oxide papers. (C) 2014 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Oxford Editor
  Language Wos 000348016500004 Publication Date 2014-08-30
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0968-4328; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.98 Times cited 13 Open Access
  Notes Approved Most recent IF: 1.98; 2015 IF: 1.988
  Call Number c:irua:123800 Serial 2467
Permanent link to this record
 

 
Author Cabana, L.; Ke, X.; Kepić, D.; Oro-Solé, J.; Tobías-Rossell, E.; Van Tendeloo, G.; Tobias, G.
  Title The role of steam treatment on the structure, purity and length distribution of multi-walled carbon nanotubes Type A1 Journal article
  Year 2015 Publication Carbon Abbreviated Journal Carbon
  Volume 93 Issue 93 Pages 1059-1067
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Purification and shortening of carbon nanotubes have attracted a great deal of attention to increase the biocompatibility and performance of the material in several applications. Steam treatment has been employed to afford both purification and shortening of multi-walled carbon nanotubes (MWCNTs). Steam removes the amorphous carbon and the graphitic particles that sheath catalytic nanoparticles, facilitating their removal by a subsequent acidic wash. The amount of metal impurities can be reduced in this manner below 0.01 wt.%. The length distribution of MWCNTs after different steam treatment times (from 1 h to 15 h) was assessed by box plot analysis of the electron microscopy data. Samples with a median length of 0.57 μm have been prepared with the reported methodology while preserving the integrity of the tubular wall structure.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Oxford Editor
  Language Wos 000360292100108 Publication Date 2015-06-23
  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 17 Open Access
  Notes 312483 Esteem2; 290023 Raddel; esteem2_ta Approved Most recent IF: 6.337; 2015 IF: 6.196
  Call Number c:irua:127691 c:irua:127691 Serial 2921
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Author Adam, N.; Leroux, F.; Knapen, D.; Bals, S.; Blust, R.
  Title The uptake and elimination of ZnO and CuO nanoparticles in Daphnia magna under chronic exposure scenarios Type A1 Journal article
  Year 2015 Publication Water research Abbreviated Journal Water Res
  Volume 68 Issue 68 Pages 249-261
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Veterinary physiology and biochemistry
  Abstract In this study, the uptake and elimination of ZnO and CuO nanoparticles in Daphnia magna was tested. Daphnids were exposed during 10 days to sublethal concentrations of ZnO and CuO nanoparticles and corresponding metal salts (ZnCl2 and CuCl2.2H2O), after which they were transferred to unexposed medium for another 10 days. At different times during the exposure and none-exposure, the total and internal zinc or copper concentration of the daphnids was determined and the nanoparticles were localized in the organism using electron microscopy. The exposure concentrations were characterized by measuring the dissolved, nanoparticle and aggregated fraction in the medium. The results showed that the ZnO nanoparticles quickly dissolved after addition to the medium. Contrarily, only a small fraction (corresponding to the dissolved metal salt) of the CuO nanoparticles dissolved, while most of these nanoparticles formed large aggregates. Despite an initial increase in zinc and copper concentration during the first 48 hour to 5 day exposure, the body concentration reached a plateau level that was comparable for the ZnO nanoparticles and ZnCl2, but much higher for the CuO nanoparticles (with visible aggregates accumulating in the gut) than CuCl2.2H2O. During the remaining exposure and subsequent none-exposure phase, the zinc and copper concentration decreased fast to concentrations comparable with the unexposed daphnids. The results indicate that D. magna can regulate its internal zinc and copper concentration after exposure to ZnO and CuO nanoparticles, similar as after exposure to metal salts. The combined dissolution, accumulation and toxicity results confirm that the toxicity of ZnO and CuO nanoparticles is caused by the dissolved fraction. Keywords nano; zinc; copper; dissolution; aggregation; electron microscopy
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Oxford Editor
  Language Wos 000347756900022 Publication Date 2014-10-14
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0043-1354; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 6.942 Times cited 51 Open Access OpenAccess
  Notes ; The authors would like to thank Valentine Mubiana and Steven Joosen (Sphere, UA) for performing the ICP-MS and ICP-OES measurements and Prof. Dr. Gustaaf Van Tendeloo for making the collaboration between the EMAT and Sphere group possible. This study is part of the ENNSATOX-project, which was funded by the EU (NMP4-SL-2009-229244). The authors report no conflicts of interest. ; Approved Most recent IF: 6.942; 2015 IF: 5.528
  Call Number c:irua:119366 c:irua:119366 Serial 3822
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Author Ercolani, G.; Gorle, C.; Garcia Sánchez, C.; Corbari, C.; Mancini, M.
  Title RAMS and WRF sensitivity to grid spacing in large-eddy simulations of the dry convective boundary layer Type A1 Journal article
  Year 2015 Publication Computers and fluids Abbreviated Journal Comput Fluids
  Volume 123 Issue 123 Pages 54-71
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Large-eddy simulations (LESS) are frequently used to model the planetary boundary layer, and the choice of the grid cell size, numerical schemes and sub grid model can significantly influence the simulation results. In the present paper the impact of grid spacing on LES of an idealized atmospheric convective boundary layer (CBL), for which the statistics and flow structures are well understood, is assessed for two mesoscale models: the Regional Atmospheric Modeling System (RAMS) and the Weather Research and Forecasting model (WRF). Nine simulations are performed on a fixed computational domain (6 x 6 x 2 km), combining three different horizontal (120, 60, 30 m) and vertical (20, 10, 5 m) spacings. The impact of the cell size on the CBL is investigated by comparing turbulence statistics and velocity spectra. The results demonstrate that both WRF and RAMS can perform LES of the CBL under consideration without requiring extremely high computational loads, but they also indicate the importance of adopting a computational grid that is adequate for the numerical schemes and subgrid models used. In both RAMS and WRF a horizontal cell size of 30 m is required to obtain a suitable turbulence reproduction throughout the CBL height. Considering the vertical grid spacing, WRF produced similar results for all the three tested values, while in RAMS it should be ensured that the aspect ratio of the cells does not exceed a value of 3. The two models were found to behave differently in function of the grid resolution, and they have different shortcomings in their prediction of CBL turbulence. WRF exhibits enhanced damping at the smallest scales, while RAMS is prone to the appearance of spurious fluctuations in the flow when the grid aspect ratio is too high. (C) 2015 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Oxford Editor
  Language Wos 000365367500006 Publication Date 2015-10-08
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0045-7930 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.313 Times cited 3 Open Access
  Notes Approved Most recent IF: 2.313; 2015 IF: 1.619
  Call Number UA @ lucian @ c:irua:130200 Serial 4236
Permanent link to this record
 

 
Author Zhang, L.-F.; Covaci, L.; Peeters, F.M.
  Title Position-dependent effect of non-magnetic impurities on superconducting properties of nanowires Type A1 Journal article
  Year 2015 Publication Europhysics letters Abbreviated Journal Epl-Europhys Lett
  Volume 109 Issue 109 Pages 17010
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Anderson's theorem states that non-magnetic impurities do not change the bulk properties of conventional superconductors. However, as the dimensionality is reduced, the effect of impurities becomes more significant. Here we investigate superconducting nanowires with diameter comparable to the Fermi wavelength $\lambda_F$ (which is less than the superconducting coherence length) by using a microscopic description based on the Bogoliubov-de Gennes method. We find that: 1) impurities strongly affect the superconducting properties, 2) the effect is impurity position dependent, and 3) it exhibits opposite behavior for resonant and off-resonant wire widths. We show that this is due to the interplay between the shape resonances of the order parameter and the subband energy spectrum induced by the lateral quantum confinement. These effects can be used to manipulate the Josephson current, filter electrons by subband and investigate the symmetries of the superconducting subband gaps.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) Paris Editor
  Language Wos 000348592100029 Publication Date 2015-01-21
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0295-5075 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.957 Times cited 7 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vlaanderen) and the Methusalem funding of the Flemish Government. ; Approved Most recent IF: 1.957; 2015 IF: 2.095
  Call Number UA @ lucian @ c:irua:128424 Serial 4227
Permanent link to this record
 

 
Author Sankaran, K.; Clima, S.; Mees, M.; Pourtois, G.
  Title Exploring alternative metals to Cu and W for interconnects applications using automated first-principles simulations Type A1 Journal article
  Year 2015 Publication ECS journal of solid state science and technology Abbreviated Journal Ecs J Solid State Sc
  Volume 4 Issue 4 Pages N3127-N3133
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract The bulk properties of elementary metals and copper based binary alloys have been investigated using automated first-principles simulations to evaluate their potential to replace copper and tungsten as interconnecting wires in the coming CMOS technology nodes. The intrinsic properties of the screened candidates based on their cohesive energy and on their electronic properties have been used as a metrics to reflect their resistivity and their sensitivity to electromigration. Using these values, the 'performances' of the alloys have been benchmarked with respect to the Cu and W ones. It turns out that for some systems, alloying Cu with another element leads to a reduced tendency to electromigration. This is however done at the expense of a decrease of the conductivity of the alloy with respect to the bulk metal. (C) 2014 The Electrochemical Society. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Electrochemical society Place of Publication (up) Pennington (N.J.) Editor
  Language Wos 000349547900018 Publication Date 2014-11-19
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2162-8769;2162-8777; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.787 Times cited 19 Open Access
  Notes Approved Most recent IF: 1.787; 2015 IF: 1.558
  Call Number c:irua:125296 Serial 1150
Permanent link to this record
 

 
Author Papageorgiou, D.G.; Filippousi, M.; Pavlidou, E.; Chrissafis, K.; Van Tendeloo, G.; Bikiaris, D.
  Title Effect of clay modification on structureproperty relationships and thermal degradation kinetics of \beta-polypropylene/clay composite materials Type A1 Journal article
  Year 2015 Publication Journal of thermal analysis and calorimetry Abbreviated Journal J Therm Anal Calorim
  Volume 122 Issue 122 Pages 393-406
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The influence of neat and organically modified montmorillonite on the structureproperty relationships of a β-nucleated polypropylene matrix has been thoroughly investigated. High-angle annular dark field scanning transmission electron microscopy revealed that the organic modification of clay facilitated the dispersion of the clay, while X-ray diffractograms showed the α-nucleating effect of the clays on the β-nucleated matrix. The results from tensile tests showed that the organic modification of MMT affected profoundly only the tensile strength at yield and at break. The effect of the organic modification of the clay on the thermal stability of the composites was finally evaluated by thermogravimetric analysis, where the samples filled with oMMT decomposed faster than the ones filled with neat MMT, due to the decomposition of the organic salts that were initially used for the modification of MMT. A kinetics study of the thermal degradation of the composites was also performed, in order to export additional conclusions on the activation energy of the samples.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) S.l. Editor
  Language Wos 000361431200042 Publication Date 2015-04-29
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1388-6150;1588-2926; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.953 Times cited 7 Open Access
  Notes 262348 Esmi Approved Most recent IF: 1.953; 2015 IF: 2.042
  Call Number c:irua:127492 Serial 805
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Author Zhang, F.; Vanmeensel, K.; Batuk, M.; Hadermann, J.; Inokoshi, M.; Van Meerbeek, B.; Naert, I.; Vleugels, J.
  Title Highly-translucent, strong and aging-resistant 3Y-TZP ceramics for dental restoration by grain boundary segregation Type A1 Journal article
  Year 2015 Publication Acta biomaterialia Abbreviated Journal Acta Biomater
  Volume 16 Issue 16 Pages 215-222
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Latest trends in dental restorative ceramics involve the development of full-contour 3Y-TZP ceramics which can avoid chipping of veneering porcelains. Among the challenges are the low translucency and the hydrothermal stability of 3Y-TZP ceramics. In this work, different trivalent oxides (Al2O3, Sc2O3, Nd2O3 and La2O3) were selected to dope 3Y-TZP ceramics. Results show that dopant segregation was a key factor to design hydrothermally stable and high-translucent 3Y-TZP ceramics and the cation dopant radius could be used as a controlling parameter. A large trivalent dopant, oversized as compared to Zr4+, exhibiting strong segregation at the ZrO2 grain boundary was preferred. The introduction of 0.2 mol% La2O3 in conventional 0.10.25 wt.% Al2O3-doped 3Y-TZP resulted in an excellent combination of high translucency and superior hydrothermal stability, while retaining excellent mechanical properties.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) S.l. Editor
  Language Wos 000351978600021 Publication Date 2015-02-04
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1742-7061; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 6.319 Times cited 54 Open Access
  Notes Fwo G043110n Approved Most recent IF: 6.319; 2015 IF: 6.025
  Call Number c:irua:124421 Serial 1473
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Author Conings, B.; Drijkoningen, J.; Gauquelin, N.; Babayigit, A.; D'Haen, J.; D'Olieslaeger, L.; Ethirajan, A.; Verbeeck, J.; Manca, J.; Mosconi, E.; Angelis, F.D.; Boyen, H.G.;
  Title Intrinsic thermal instability of methylammonium lead trihalide perovskite Type A1 Journal article
  Year 2015 Publication Laser physics review Abbreviated Journal Adv Energy Mater
  Volume 5 Issue 5 Pages 1500477
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Organolead halide perovskites currently are the new front-runners as light absorbers in hybrid solar cells, as they combine efficiencies passing already 20% with deposition temperatures below 100 °C and cheap solution-based fabrication routes. Long-term stability remains a major obstacle for application on an industrial scale. Here, it is demonstrated that significant decomposition effects already occur during annealing of a methylammonium lead triiode perovskite at 85 °C even in inert atmosphere thus violating international standards. The observed behavior supports the view of currently used perovskite materials as soft matter systems with low formation energies, thus representing a major bottleneck for their application, especially in countries with high average temperatures. This result can trigger a broader search for new perovskite families with improved thermal stability.
  Address
  Corporate Author Thesis
  Publisher Place of Publication (up) S.l. Editor
  Language Wos 000359374900005 Publication Date 2015-06-03
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1614-6832; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 16.721 Times cited 1691 Open Access
  Notes FWO G004413N; GOA Solarpaint Approved Most recent IF: 16.721; 2015 IF: 16.146
  Call Number c:irua:127298UA @ admin @ c:irua:127298 Serial 1719
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Author Guerrero, A.; Heidari, H.; Ripolles, T.S.; Kovalenko, A.; Pfannmöller, M.; Bals, S.; Kauffmann, L.-D.; Bisquert, J.; Garcia-Belmonte, G.
  Title Shelf life degradation of bulk heterojunction solar cells : intrinsic evolution of charge transfer complex Type A1 Journal article
  Year 2015 Publication Laser physics review Abbreviated Journal Adv Energy Mater
  Volume 5 Issue 5 Pages 1401997
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
  Abstract Achievement of long-term stability of organic photovoltaics is currently one of the major topics for this technology to reach maturity. Most of the techniques used to reveal degradation pathways are destructive and/or do not allow for real-time measurements in operating devices. Here, three different, nondestructive techniques able to provide real-time information, namely, film absorbance, capacitance-voltage (C-V), and impedance spectroscopy (IS), are combined over a period of 1 year using non-accelerated intrinsic degradation conditions. It is discerned between chemical modifications in the active layer, physical processes taking place in the bulk of the blend from those at the active layer/contact interfaces. In particular, it is observed that during the ageing experiment, the main source for device performance degradation is the formation of donor-acceptor charge-transfer complex (P3HT(center dot+)-PCBM center dot-) that acts as an exciton quencher. Generation of these radical species diminishes photocurrent and reduces open-circuit voltage by the creation of electronic defect states. Conclusions extracted from absorption, C-V, and IS measurements will be further supported by a range of other techniques such as atomic force microscopy, X-ray diffraction, and dark-field imaging of scanning transmission electron microscopy on ultrathin cross-sections.
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  Corporate Author Thesis
  Publisher Place of Publication (up) S.l. Editor
  Language Wos 000352708600013 Publication Date 2014-12-12
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1614-6832; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 16.721 Times cited 30 Open Access OpenAccess
  Notes 287594 Sunflower; 335078 Colouratom; ECAS_Sara; (ROMEO:yellow; preprint:; postprint:restricted ; pdfversion:cannot); Approved Most recent IF: 16.721; 2015 IF: 16.146
  Call Number c:irua:126000 Serial 2994
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