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Author Singh, S.K.; Neek-Amal, M.; Peeters, F.M.
  Title Electronic properties of graphene nano-flakes : energy gap, permanent dipole, termination effect, and Raman spectroscopy Type A1 Journal article
  Year 2014 Publication The journal of chemical physics Abbreviated Journal J Chem Phys
  Volume 140 Issue 7 Pages 074304-74309
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The electronic properties of graphene nano-flakes (GNFs) with different edge passivation are investigated by using density functional theory. Passivation with F and H atoms is considered: C-Nc X-Nx (X = F or H). We studied GNFs with 10 < N-c < 56 and limit ourselves to the lowest energy configurations. We found that: (i) the energy difference Delta between the highest occupied molecular orbital and the lowest unoccupied molecular orbital decreases with N-c, (ii) topological defects (pentagon and heptagon) break the symmetry of the GNFs and enhance the electric polarization, (iii) the mutual interaction of bilayer GNFs can be understood by dipole-dipole interaction which were found sensitive to the relative orientation of the GNFs, (iv) the permanent dipoles depend on the edge terminated atom, while the energy gap is independent of it, and (v) the presence of heptagon and pentagon defects in the GNFs results in the largest difference between the energy of the spin-up and spin-down electrons which is larger for the H-passivated GNFs as compared to F-passivated GNFs. Our study shows clearly the effect of geometry, size, termination, and bilayer on the electronic properties of small GNFs. This study reveals important features of graphene nano-flakes which can be detected using Raman spectroscopy. (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher Place of Publication New York, N.Y. Editor
  Language Wos 000332039900020 Publication Date 2014-02-20
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-9606;1089-7690; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.965 Times cited 30 Open Access
  Notes ; This work was supported by the EU-Marie Curie IIF postdoctoral Fellowship/ 299855 (for M. N.-A.), the ESF-EuroGRAPHENE project CONGRAN, the Flemish Science Foundation (FWO-Vl), and the Methusalem Foundation of the Flemish Government. ; Approved Most recent IF: 2.965; 2014 IF: 2.952
  Call Number UA @ lucian @ c:irua:115857 Serial 1002
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Author Bal, K.M.; Neyts, E.C.
  Title On the time scale associated with Monte Carlo simulations Type A1 Journal article
  Year 2014 Publication The journal of chemical physics Abbreviated Journal J Chem Phys
  Volume 141 Issue 20 Pages 204104
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract Uniform-acceptance force-bias Monte Carlo (fbMC) methods have been shown to be a powerful technique to access longer timescales in atomistic simulations allowing, for example, phase transitions and growth. Recently, a new fbMC method, the time-stamped force-bias Monte Carlo (tfMC) method, was derived with inclusion of an estimated effective timescale; this timescale, however, does not seem able to explain some of the successes the method. In this contribution, we therefore explicitly quantify the effective timescale tfMC is able to access for a variety of systems, namely a simple single-particle, one-dimensional model system, the Lennard-Jones liquid, an adatom on the Cu(100) surface, a silicon crystal with point defects and a highly defected graphene sheet, in order to gain new insights into the mechanisms by which tfMC operates. It is found that considerable boosts, up to three orders of magnitude compared to molecular dynamics, can be achieved for solid state systems by lowering of the apparent activation barrier of occurring processes, while not requiring any system-specific input or modifications of the method. We furthermore address the pitfalls of using the method as a replacement or complement of molecular dynamics simulations, its ability to explicitly describe correct dynamics and reaction mechanisms, and the association of timescales to MC simulations in general.
  Address
  Corporate Author Thesis
  Publisher Place of Publication New York, N.Y. Editor
  Language Wos 000345641400005 Publication Date 2014-11-26
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-9606;1089-7690; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.965 Times cited 26 Open Access
  Notes Approved Most recent IF: 2.965; 2014 IF: 2.952
  Call Number UA @ lucian @ c:irua:120667 Serial 2459
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Author Leus, K.; Liu, Y.-Y.; Meledina, M.; Turner, S.; Van Tendeloo, G.; van der Voort, P.
  Title A MoVI grafted metal organic framework : synthesis, characterization and catalytic investigations Type A1 Journal article
  Year 2014 Publication Journal of catalysis Abbreviated Journal J Catal
  Volume 316 Issue Pages 201-209
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract We present the post-modification of a gallium based Metal Organic Framework, COMOC-4, with a Mo-complex. The resulting Mo@COMOC-4 was characterized by means of N2 sorption, XRPD, DRIFT, TGA, XRF, XPS and TEM analysis. The results demonstrate that even at high Mo-complex loadings on the framework, no aggregation or any Mo or Mo oxide species are formed. Moreover, the Mo@COMOC-4 was evaluated as a catalyst in the epoxidation of cyclohexene, cyclooctene and cyclododecene employing TBHP in decane as oxidant. The post-modified COMOC-4 exhibits a very high selectivity toward the epoxide (up to 100%). Regenerability and stability tests have been carried out demonstrating that the catalyst can be recycled without leaching of Mo or loss of crystallinity.
  Address
  Corporate Author Thesis
  Publisher Place of Publication San Diego, Calif. Editor
  Language Wos 000340853800020 Publication Date 2014-06-19
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-9517; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 6.844 Times cited 36 Open Access
  Notes European Research Council under the Seventh Framework Program (FP7); ; ERC Grant No. 246791 – COUNTATOMS; Hercules; FWO Approved Most recent IF: 6.844; 2014 IF: 6.921
  Call Number UA @ lucian @ c:irua:117416 Serial 3546
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Author Zhang, Y.; Jiang, W.; Zhang, Q.Z.; Bogaerts, A.
  Title Computational study of plasma sustainability in radio frequency micro-discharges Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 115 Issue 19 Pages 193301-193311
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract We apply an implicit particle-in-cell Monte-Carlo (PIC-MC) method to study a radio-frequency argon microdischarge at steady state in the glow discharge limit, in which the microdischarge is sustained by secondary electron emission from the electrodes. The plasma density, electron energy distribution function (EEDF), and electron temperature are calculated in a wide range of operating conditions, including driving voltage, microdischarge gap, and pressure. Also, the effect of gap size scaling (in the range of 50-1000 μm) on the plasma sustaining voltage and peak electron density at atmospheric pressure is examined, which has not been explored before. In our simulations, three different EEDFs, i.e., a so-called three temperature hybrid mode, a two temperature α mode, and a two temperature γ mode distribution, are identified at different gaps and voltages. The maximum sustaining voltage to avoid a transition from the glow mode to an arc is predicted, as well as the minimum sustaining voltage for a steady glow discharge. Our calculations elucidate that secondary electrons play an essential role in sustaining the discharge, and as a result the relationship between breakdown voltage and gap spacing is far away from the Paschen law at atmospheric pressure.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000336920200010 Publication Date 2014-05-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 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; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:116948 Serial 458
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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 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 (down) 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 Smets, Q.; Verreck, D.; Verhulst, A.S.; Rooyackers, R.; Merckling, C.; Van De Put, M.; Simoen, E.; Vandervorst, W.; Collaert, N.; Thean, V.Y.; Sorée, B.; Groeseneken, G.; Heyns, M.M.;
  Title InGaAs tunnel diodes for the calibration of semi-classical and quantum mechanical band-to-band tunneling models Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 115 Issue 18 Pages 184503-184509
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Promising predictions are made for III-V tunnel-field-effect transistor (FET), but there is still uncertainty on the parameters used in the band-to-band tunneling models. Therefore, two simulators are calibrated in this paper; the first one uses a semi-classical tunneling model based on Kane's formalism, and the second one is a quantum mechanical simulator implemented with an envelope function formalism. The calibration is done for In0.53Ga0.47As using several p+/intrinsic/n+ diodes with different intrinsic region thicknesses. The dopant profile is determined by SIMS and capacitance-voltage measurements. Error bars are used based on statistical and systematic uncertainties in the measurement techniques. The obtained parameters are in close agreement with theoretically predicted values and validate the semi-classical and quantum mechanical models. Finally, the models are applied to predict the input characteristics of In0.53Ga0.47As n- and p-lineTFET, with the n-lineTFET showing competitive performance compared to MOSFET.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000336919400048 Publication Date 2014-05-14
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 34 Open Access
  Notes ; Quentin Smets and Devin Verreck gratefully acknowledge the support of a Ph. D. stipend from IWT-Vlaanderen. This work was supported by imec's industrial affiliation program. The authors thank Kim Baumans, Johan Feyaerts, Johan De Cooman, Alireza Alian, and Jos Moonens for their support in process development; Bastien Douhard and Joris Delmotte for SIMS characterization; Alain Moussa for AFM characterization; Joris Van Laer and Tom Daenen for their support in electrical characterization; Kuo-Hsing Kao, Mehbuba Tanzid, and Ali Pourghaderi for their support in modeling. ; Approved Most recent IF: 2.068; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:118009 Serial 1667
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Author Milovanović, S.P.; Masir, M.R.; Peeters, F.M.
  Title Magnetic electron focusing and tuning of the electron current with a pn-junction Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 115 Issue 4 Pages 043719-6
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Transverse magnetic focusing properties of graphene using a ballistic four terminal structure are investigated. The electric response is obtained using the semiclassical billiard model. The transmission exhibits pronounced peaks as a consequence of skipping orbits at the edge of the structure. When we add a pn-junction between the two probes, snake states along the pn-interface appear. Injected electrons are guided by the pn-interface to one of the leads depending on the value of the applied magnetic field. Oscillations in the resistance are found depending on the amount of particles that end up in each lead.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000331210800066 Publication Date 2014-01-30
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 21 Open Access
  Notes This work was supported by the Flemish Science Foundation (FWO-Vl), the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN, and the Methusalem Foundation of the Flemish government. Approved Most recent IF: 2.068; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:115801 Serial 1866
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Author Sen, H.S.; Sahin, H.; Peeters, F.M.; Durgun, E.
  Title Monolayers of MoS2 as an oxidation protective nanocoating material Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 116 Issue 8 Pages 083508
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract First-principle calculations are employed to investigate the interaction of oxygen with ideal and defective MoS2 monolayers. Our calculations show that while oxygen atoms are strongly bound on top of sulfur atoms, the oxygen molecule only weakly interacts with the surface. The penetration of oxygen atoms and molecules through a defect-free MoS2 monolayer is prevented by a very high diffusion barrier indicating that MoS2 can serve as a protective layer for oxidation. The analysis is extended to WS2 and similar coating characteristics are obtained. Our calculations indicate that ideal and continuous MoS2 and WS2 monolayers can improve the oxidation and corrosion-resistance of the covered surface and can be considered as an efficient nanocoating material. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000342821600017 Publication Date 2014-08-27
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 52 Open Access
  Notes ; This work was supported by the bilateral project between TUBITAK (through Grant No. 113T050) and Flemish Science Foundation (FWO-Vl). The calculations were performed at TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure). E.D. acknowledges support from Bilim Akademisi-The Science Academy, Turkey under the BAGEP program. H.S. is supported by an FWO Pegasus-long Marie Curie Fellowship. ; Approved Most recent IF: 2.068; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:121101 Serial 2194
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Author Wen, D.-Q.; Zhang, Q.-Z.; Jiang, W.; Song, U.-H.; Bogaerts, A.; Wang, Y.-N.
  Title Phase modulation in pulsed dual-frequency capacitively coupled plasmas Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 115 Issue 23 Pages 233303
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract Particle-in-cell/Monte Carlo collision simulations, coupled with an external circuit, are used to investigate the behavior of pulsed dual-frequency (DF) capacitively coupled plasmas (CCPs). It is found that the phase shift θ between the high (or low) frequency source and the pulse modulation has a great influence on the ion density and the ionization rate. By pulsing the high frequency source, the time-averaged ion density shows a maximum when θ = 90∘. The time-averaged ion energy distribution functions (IEDFs) at the driven electrode, however, keep almost unchanged, illustrating the potential of pulsed DF-CCP for independent control of ion density (and flux) and ion energy. A detailed investigation of the temporal evolution of the plasma characteristics indicates that several high frequency harmonics can be excited at the initial stage of a pulse period by tuning the phase shift θ, and this gives rise to strong sheath oscillations, and therefore high ionization rates. For comparison, the pulsing of the low frequency source is also studied. In this case, the ion density changes slightly as a function of time, and the time-averaged ion density shows the same trend as in the HF modulation for different phase shifts θ. Moreover, the time-averaged IEDFs at the driven electrode can be modulated, showing the potential to reduce the maximum ion bombardment energy.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000338106000008 Publication Date 2014-06-23
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 8 Open Access
  Notes Approved Most recent IF: 2.068; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:117415 Serial 2585
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Author Verreck, D.; Van de Put, M.; Sorée, B.; Verhulst, A.S.; Magnus, W.; Vandenberghe, W.G.; Collaert, N.; Thean, A.; Groeseneken, G.
  Title Quantum mechanical solver for confined heterostructure tunnel field-effect transistors Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 115 Issue 5 Pages 053706-53708
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Heterostructure tunnel field-effect transistors (HTFET) are promising candidates for low-power applications in future technology nodes, as they are predicted to offer high on-currents, combined with a sub-60 mV/dec subthreshold swing. However, the effects of important quantum mechanical phenomena like size confinement at the heterojunction are not well understood, due to the theoretical and computational difficulties in modeling realistic heterostructures. We therefore present a ballistic quantum transport formalism, combining a novel envelope function approach for semiconductor heterostructures with the multiband quantum transmitting boundary method, which we extend to 2D potentials. We demonstrate an implementation of a 2-band version of the formalism and apply it to study confinement in realistic heterostructure diodes and p-n-i-n HTFETs. For the diodes, both transmission probabilities and current densities are found to decrease with stronger confinement. For the p-n-i-n HTFETs, the improved gate control is found to counteract the deterioration due to confinement. (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000331645900040 Publication Date 2014-02-05
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 15 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; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:115825 Serial 2780
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Author Moors, K.; Sorée, B.; Tokei, Z.; Magnus, W.
  Title Resistivity scaling and electron relaxation times in metallic nanowires Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 116 Issue 6 Pages 063714
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract We study the resistivity scaling in nanometer-sized metallic wires due to surface roughness and grain-boundaries, currently the main cause of electron scattering in nanoscaled interconnects. The resistivity has been obtained with the Boltzmann transport equation, adopting the relaxation time approximation of the distribution function and the effective mass approximation for the conducting electrons. The relaxation times are calculated exactly, using Fermi's golden rule, resulting in a correct relaxation time for every sub-band state contributing to the transport. In general, the relaxation time strongly depends on the sub-band state, something that remained unclear with the methods of previous work. The resistivity scaling is obtained for different roughness and grain-boundary properties, showing large differences in scaling behavior and relaxation times. Our model clearly indicates that the resistivity is dominated by grain-boundary scattering, easily surpassing the surface roughness contribution by a factor of 10. (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000341179400036 Publication Date 2014-08-15
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 17 Open Access
  Notes ; ; Approved Most recent IF: 2.068; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:119260 Serial 2882
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Author Chen, Z.; Bogaerts, A.
  Title Response to “Comment on 'Laser ablation of Cu and plume expansion into 1 atm ambient gas'” [J. Appl. Phys. 115, 166101 (2014)] Type Editorial
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 115 Issue 16 Pages 166102
  Keywords Editorial; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000335228400092 Publication Date 2014-05-01
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 1 Open Access
  Notes Approved Most recent IF: 2.068; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:117171 Serial 2898
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Author Kao, K.-H.; Verhulst, A.S.; Van de Put, M.; Vandenberghe, W.G.; Sorée, B.; Magnus, W.; De Meyer, K.
  Title Tensile strained Ge tunnel field-effect transistors: k\cdot p material modeling and numerical device simulation Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys
  Volume 115 Issue 4 Pages 044505-44508
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Group IV based tunnel field-effect transistors generally show lower on-current than III-V based devices because of the weaker phonon-assisted tunneling transitions in the group IV indirect bandgap materials. Direct tunneling in Ge, however, can be enhanced by strain engineering. In this work, we use a 30-band k.p method to calculate the band structure of biaxial tensile strained Ge and then extract the bandgaps and effective masses at Gamma and L symmetry points in k-space, from which the parameters for the direct and indirect band-to-band tunneling (BTBT) models are determined. While transitions from the heavy and light hole valence bands to the conduction band edge at the L point are always bridged by phonon scattering, we highlight a new finding that only the light-holelike valence band is strongly coupling to the conduction band at the Gamma point even in the presence of strain based on the 30-band k.p analysis. By utilizing a Technology Computer Aided Design simulator equipped with the calculated band-to-band tunneling BTBT models, the electrical characteristics of tensile strained Ge point and line tunneling devices are self-consistently computed considering multiple dynamic nonlocal tunnel paths. The influence of field-induced quantum confinement on the tunneling onset is included. Our simulation predicts that an on-current up to 160 (260) mu A/mu m can be achieved along with on/off ratio > 10(6) for V-DD = 0.5V by the n-type (p-type) line tunneling device made of 2.5% biaxial tensile strained Ge. (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000331210800113 Publication Date 2014-01-26
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8979;1089-7550; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.068 Times cited 26 Open Access
  Notes ; Authors would like to thank Dr. Mohammad Ali Pourghaderi for useful discussions on the nonparabolicity. Authors would also like to thank Professor Eddy Simoen and Dr. Yosuke Shimura for useful discussions about the validity of modeled bandgaps and effective masses. This work was also supported by IMEC's Industrial Affiliation Program. ; Approved Most recent IF: 2.068; 2014 IF: 2.183
  Call Number UA @ lucian @ c:irua:115800 Serial 3505
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Author de Nolf, W.; Vanmeert, F.; Janssens, K.
  Title XRDUA : crystalline phase distribution maps by two-dimensional scanning and tomographic (micro) X-ray powder diffraction Type A1 Journal article
  Year 2014 Publication Journal of applied crystallography Abbreviated Journal
  Volume 47 Issue 3 Pages 1107-1117
  Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
  Abstract Imaging of crystalline phase distributions in heterogeneous materials, either plane projected or in virtual cross sections of the object under investigation, can be achieved by scanning X-ray powder diffraction employing X-ray micro beams and X-ray-sensitive area detectors. Software exists to convert the two-dimensional powder diffraction patterns that are recorded by these detectors to one-dimensional diffractograms, which may be analysed by the broad variety of powder diffraction software developed by the crystallography community. However, employing these tools for the construction of crystalline phase distribution maps proves to be very difficult, especially when employing micro-focused X-ray beams, as most diffraction software tools have mainly been developed having structure solution in mind and are not suitable for phase imaging purposes. XRDUA has been developed to facilitate the execution of the complete sequence of data reduction and interpretation steps required to convert large sequences of powder diffraction patterns into a limited set of crystalline phase maps in an integrated fashion.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000336738500031 Publication Date 2014-05-28
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0021-8898 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 62 Open Access
  Notes ; The authors would like to thank the synchrotron beamline staff at ID15 (ESRF, Grenoble, France), MicroXAS (SLS, Villigen, Switzerland) and PO6/BL-L (Petra III/Hasylab, Hamburg, Germany) for accommodating the experiments presented in this paper. Support from FWO 'Big Science' project G0C1213N as well as from the BELSPO project 'S2ART' (SD/RI/04A) is acknowledged. ; Approved Most recent IF: NA
  Call Number UA @ admin @ c:irua:117758 Serial 5920
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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 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 (down) 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 Abakumov, A.M.; Morozov, V.A.; Tsirlin, A.A.; Verbeeck, J.; Hadermann, J.
  Title Cation ordering and flexibility of the BO42- tetrahedra in incommensurately modulated CaEu2(BO4)4 (B = Mo, W) scheelites Type A1 Journal article
  Year 2014 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
  Volume 53 Issue 17 Pages 9407-9415
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The factors mediating cation ordering in the scheelite-based molybdates and tungstates are discussed on the basis of the incommensurately modulated crystal structures of the CaEu2(BO4)(4) (B = Mo, W) red phosphors solved from high-resolution synchrotron powder X-ray diffraction data. Monoclinic CaEu2(WO4)(4) adopts a (3 + 1)-dimensionally modulated structure [superspace group I2/b(alpha beta 0)00, a = 5.238 73(1)A, b = 5.266 35(1) A, c = 11.463 19(9) A, gamma = 91.1511(2)degrees, q = 0.56153(6)a* + 0.7708(9)b*, R-F = 0.050, R-p = 0.069], whereas tetragonal CaEu2(MoO4)(4) is (3 + 2)-dimensionally modulated [superspace group I4(1)/ a(alpha beta 0)00(-beta alpha 0)00, a = 5.238 672(7) A, c = 11.548 43(2) A, q(1) = 035331(8)a* + 0.82068(9)b*, q(2) = -0.82068(9)a* + 0.55331(8)b*, R-F = 0.061, R-p = 0.082]. In both cases the modulation arises from the ordering of the Ca/Eu cations and the cation vacancies at the A-sublattice of the parent scheelite ABO(4) structure. The cation ordering is incomplete and better described with harmonic rather than with steplike occupational modulation functions. The structures respond to the variation of the effective charge and cation size at the A-position through the flexible geometry of the MoO42- and WO42- tetrahedra demonstrating an alternation of stretching the B-O bond lengths and bending the O-B-O bond angles. The tendency towards A-site cation ordering in scheelites is rationalized using the difference in ionic radii and concentration of the A-site vacancies as parameters and presented in the form of a structure map.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Easton, Pa Editor
  Language Wos 000341229600068 Publication Date 2014-08-21
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.857 Times cited 48 Open Access
  Notes Fwo G039211n Approved Most recent IF: 4.857; 2014 IF: 4.762
  Call Number UA @ lucian @ c:irua:119292UA @ admin @ c:irua:119292 Serial 297
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Author Malo, S.; Abakumov, A.M.; Daturi, M.; Pelloquin, D.; Van Tendeloo, G.; Guesdon, A.; Hervieu, M.
  Title Sr21Bi8Cu2(CO3)(2)O-41, a Bi5+ Oxycarbonate with an Original 10L Structure Type A1 Journal article
  Year 2014 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
  Volume 53 Issue 19 Pages 10266-10275
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The layered structure of Sr21Bi8Cu2(CO3)(2)O-41 (Z = 2) was determined by transmission electron microscopy, infrared spectroscopy, and powder X-ray diffraction refinement in space group P6(3)/mcm (No. 194), with a = 10.0966(3)angstrom and c = 26.3762(5)angstrom. This original 10L-type structure is built from two structural blocks, namely, [Sr15Bi6Cu2(CO3)O-29] and [Sr6Bi2(CO3)O-12]. The Bi5+ cations form [Bi2O10] dimers, whereas the Cu2+ and C atoms occupy infinite tunnels running along (c) over right arrow. The nature of the different blocks and layers is discussed with regard to the existing hexagonal layered compounds. Sr21Bi8Cu2(CO3)(2)O-41 is insulating and paramagnetic.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Easton, Pa Editor
  Language Wos 000342856800039 Publication Date 2014-10-06
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record
  Impact Factor 4.857 Times cited Open Access
  Notes Approved Most recent IF: 4.857; 2014 IF: 4.762
  Call Number UA @ lucian @ c:irua:121115 Serial 3114
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Author Charkin, D.O.; Demchyna, R.; Prots, Y.; Borrmann, H.; Burkhardt, U.; Schwarz, U.; Schnelle, W.; Plokhikh, I.V.; Kazakov, S.M.; Abakumov, A.M.; Batuk, D.; Verchenko, V.Y.; Tsirlin, A.A.; Curfs, C.; Grin, Y.; Shevelkov, A.V.;
  Title Two New Arsenides, Eu7Cu44As23 and Sr7Cu44As23, With a New Filled Variety of the BaHg11 Structure Type A1 Journal article
  Year 2014 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
  Volume 53 Issue 20 Pages 11173-11184
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Two new ternary arsenides, namely, Eu7Cu44As23 and Sr7Cu44As23, were synthesized from elements at 800 degrees C. Their crystal structure represents a new filled version of the BaHg11 motif with cubic voids alternately occupied by Eu(Sr) and As atoms, resulting in a 2 x 2 x 2 superstructure of the aristotype: space group Fm (3) over barm, a = 16.6707(2) angstrom and 16.7467(2) angstrom, respectively. The Eu derivative exhibits ferromagnetic ordering below 17.5 K. In agreement with band structure calculations both compounds are metals, exhibiting relatively low thermopower, but high electrical and low thermal conductivity.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Easton, Pa Editor
  Language Wos 000343527700049 Publication Date 2014-09-29
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.857 Times cited 9 Open Access
  Notes Approved Most recent IF: 4.857; 2014 IF: 4.762
  Call Number UA @ lucian @ c:irua:121141 Serial 3784
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Author Radvanyi, E.; Van Havenbergh, K.; Porcher, W.; Jouanneau, S.; Bridel, J.-S.; Put, S.; Franger, S.
  Title Study and modeling of the Solid Electrolyte Interphase behavior on nano-silicon anodes by Electrochemical Impedance Spectroscopy Type A1 Journal article
  Year 2014 Publication Electrochimica acta Abbreviated Journal Electrochim Acta
  Volume 137 Issue Pages 751-757
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The instability of the Solid Electrolyte Interphase (SEI) at the surface of nano-silicon electrodes has been recognized as one of the key issues to explain the rapid capacity fading of theses electrodes. In this paper, two distinct Si-based systems are studied by using Electrochemical Impedance Spectroscopy (EIS). First, several EIS spectra are recorded along the second electrochemical cycle. Although the active material, the electrode formulation, and the experimental conditions are different for the two systems, the same phenomena are observed in both cases: (i) the SEI deposit around 50 kHz, (ii) the charge transfer (CT) with a characteristic frequency varying from 300 to 1 500 Hz, and (iii) an inductive loop at ∼1 Hz which appears only when the potential of the electrode is below 0.35 V vs Li. As the latter has never been reported for Si-based electrodes, the second step of the work consists in understanding this phenomenon. Thanks to the results obtained in a set of several complementary experiments, we finally attribute the inductive loop to the constant formation/deposition of SEI products, in competition with the CT process. In addition, we propose a mechanism for this specific phenomenon and the equivalent circuit to fit the recorded EIS spectra.
  Address
  Corporate Author Thesis
  Publisher Place of Publication London Editor
  Language Wos 000341462500095 Publication Date 2014-06-19
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0013-4686; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.798 Times cited 36 Open Access
  Notes IWT (K. Van Havenbergh) Approved Most recent IF: 4.798; 2014 IF: 4.504
  Call Number UA @ lucian @ c:irua:117945 Serial 3323
Permanent link to this record
 

 
Author Hoffman, B.M.; Lukoyanov, D.; Yang, Z.-Y.; Dean, D.R.; Seefeldt, L.C.
  Title Mechanism of Nitrogen Fixation by Nitrogenase: The Next Stage Type A1 Journal Article
  Year 2014 Publication Chemical Reviews Abbreviated Journal Chem. Rev.
  Volume 114 Issue 8 Pages 4041-4062
  Keywords A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
  Abstract Ammonia is a crucial nutrient used for plant growth and as a building block in pharmaceutical and chemical industry, produced via nitrogen fixation of the ubiquitous atmospheric N2. Current industrial ammonia production relies heavily on fossil resources, but a lot of work is put into developing non-fossil based pathways. Among these is the use of nonequilibrium plasma. In this work, we investigated water vapor as H source for nitrogen fixation into NH3 by non-equilibrium plasma. The highest selectivity towards NH3 was observed with low amounts of added H2O vapor, but the highest production rate was reached at high H2O vapor.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos Publication Date 2014-04-23
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0009-2665 ISBN Additional Links
  Impact Factor Times cited Open Access
  Notes We would like to thank Sylvia Dewilde (Department of Biomedical Sciences) for providing analytical equipment. Approved no
  Call Number PLASMANT @ plasmant @ Serial 6337
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Author Dekov, V.M.; Vanlierde, E.; Billström, K.; Gatto Rotondo, G.; van Meel, K.; Darchuk, L.; Van Grieken, R.; et al.
  Title Ferrihydrite precipitation in groundwater-fed river systems (Nete and Demer river basins, Belgium) : insights from a combined Fe-Zn-Sr-Nd-Pb-isotope study Type A1 Journal article
  Year 2014 Publication Chemical geology Abbreviated Journal
  Volume 386 Issue Pages 1-15
  Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
  Abstract Two groundwater-fed river systems (Nete and Demer, Belgium) carry red suspended material that settles on the river bed forming red sediments. The local aquifer that feeds these river systems is a glauconite-rich sand, which provides most of the dissolved Fe to the rivers. The solid component of these systems, i.e., the red suspended material and sediments, has a simple mineralogy (predominantly ferrihydrite), but shows a complex geochemistry pointing out the different processes contributing to the river chemistry: (1) the red sediments have higher transition metal (excluding Cu) and detrital element (e.g., Si, Al, K, Rb, etc.) concentrations than the red suspended matter because of their longer residence time in the river and higher contribution of the background (aquifer) component, respectively; (2) the red suspended material and sediments have inherited their rare earth element (REE) patterns from the aquifer; (3) the origin of Sr present in the red suspended matter and red sediments is predominantly marine (i.e., Quaternary calcareous rocks), but a small amount is geogenic (i.e., from detrital rocks); (4) Pb in both solids originates mostly from anthropogenic and geogenic sources; (5) all of the anthropogenic Pb in the red suspended material and sediments is hosted by the ferrihydrite; (6) Nd budget of the red riverine samples is controlled by the geogenic source and shows little anthropogenic component; (7) the significant Fe- and Zn-isotope fractionations are in line with the previous studies. Their fractionation patterns do not correlate, suggesting that the processes controlling the isotope geochemistry of Fe and Zn are different: oxidation/reduction most likely governs the Fe-isotope fractionation, whereas adsorption/desorption or admixing of anthropogenic sources controls the isotope fractionation of Zn.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000345441000001 Publication Date 2014-08-08
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0009-2541 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:118323 Serial 7962
Permanent link to this record
 

 
Author da Costa, D.R.; Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M.
  Title Analytical study of the energy levels in bilayer graphene quantum dots Type A1 Journal article
  Year 2014 Publication Carbon Abbreviated Journal Carbon
  Volume 78 Issue Pages 392-400
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Using the four-band continuum model we derive a general expression for the infinite-mass boundary condition in bilayer graphene. Applying this new boundary condition we analytically calculate the confined states and the corresponding wave functions in a bilayer graphene quantum dot in the absence and presence of a perpendicular magnetic field. Our results for the energy spectrum show an energy gap between the electron and hole states at small magnetic fields. Furthermore the electron (e) and hole (h) energy levels corresponding to the K and K' valleys exhibit the E-K(e(h)) (m) = E-K'(e(h)) (m) symmetry, where m is the angular momentum quantum number. (C) 2014 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Oxford Editor
  Language Wos 000341463900042 Publication Date 2014-07-16
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0008-6223; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 6.337 Times cited 35 Open Access
  Notes ; This work was financially supported by CNPq, under contract NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES Foundation under the process number BEX 7178/13-1, the Flemish Science Foundation (FWO-Vl), the European Science Foundation (ESF) under the EUROCORES program Euro-GRAPHENE (project CONGRAN), the Bilateral programme between CNPq and FWO-Vl, and the Brazilian Program Science Without Borders (CsF). We thank M. Ramezani Masir and M. Grujic for helpful comments and discussions. ; Approved Most recent IF: 6.337; 2014 IF: 6.196
  Call Number UA @ lucian @ c:irua:119280 Serial 109
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Author Neyts, E.C.; Bogaerts, A.
  Title Ion irradiation for improved graphene network formation in carbon nanotube growth Type A1 Journal article
  Year 2014 Publication Carbon Abbreviated Journal Carbon
  Volume 77 Issue Pages 790-795
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract Ion irradiation of carbon nanotubes very often leads to defect formation. However, we have recently shown that Ar ion irradiation in a limited energy window of 1025 eV may enhance the initial cap nucleation process, when the carbon network is in contact with the metal nanocatalyst. Here, we employ reactive molecular dynamics simulations to demonstrate that ion irradiation in a higher energy window of 1035 eV may also heal network defects after the nucleation stage through a non-metal-mediated mechanism, when the carbon network is no longer in contact with the metal nanocatalyst. The results demonstrate the possibility of beneficially utilizing ions in e.g. plasma-enhanced chemical vapour deposition of carbon nanotubes.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Oxford Editor
  Language Wos 000340689400083 Publication Date 2014-06-11
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0008-6223; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 6.337 Times cited 7 Open Access
  Notes Approved Most recent IF: 6.337; 2014 IF: 6.196
  Call Number UA @ lucian @ c:irua:118062 Serial 1745
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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 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 (down) 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
Permanent link to this record
 

 
Author Jungbauer, M.; Huehn, S.; Egoavil, R.; Tan, H.; Verbeeck, J.; Van Tendeloo, G.; Moshnyaga, V.
  Title Atomic layer epitaxy of Ruddlesden-Popper SrO(SrTiO3)n films by means of metalorganic aerosol deposition Type A1 Journal article
  Year 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 105 Issue 25 Pages 251603
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract We report an atomic layer epitaxial growth of Ruddlesden-Popper (RP) thin films of SrO(SrTiO3)(n) (n = infinity, 2, 3, 4) by means of metalorganic aerosol deposition (MAD). The films are grown on SrTiO3(001) substrates by means of a sequential deposition of Sr-O/Ti-O-2 atomic monolayers, monitored in-situ by optical ellipsometry. X-ray diffraction and transmission electron microscopy (TEM) reveal the RP structure with n = 2-4 in accordance with the growth recipe. RP defects, observed by TEM in a good correlation with the in-situ ellipsometry, mainly result from the excess of SrO. Being maximal at the film/substrate interface, the SrO excess rapidly decreases and saturates after 5-6 repetitions of the SrO(SrTiO3)(4) block at the level of 2.4%. This identifies the SrTiO3 substrate surface as a source of RP defects under oxidizing conditions within MAD. Advantages and limitations of MAD as a solution-based and vacuum-free chemical deposition route were discussed in comparison with molecular beam epitaxy. (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000346914000007 Publication Date 2014-12-26
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0003-6951;1077-3118; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.411 Times cited 32 Open Access
  Notes 246102 IFOX; 278510 VORTEX; 246791 COUNTATOMS; Hercules; 312483 ESTEEM2; esteem2jra3 ECASJO; Approved Most recent IF: 3.411; 2014 IF: 3.302
  Call Number UA @ lucian @ c:irua:122830UA @ admin @ c:irua:122830 Serial 172
Permanent link to this record
 

 
Author da Silva, R.M.; Milošević, M.V.; Dominguez, D.; Peeters, F.M.; Albino Aguiar, J.
  Title Distinct magnetic signatures of fractional vortex configurations in multiband superconductors Type A1 Journal article
  Year 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 105 Issue 23 Pages 232601
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Vortices carrying fractions of a flux quantum are predicted to exist in multiband superconductors, where vortex core can split between multiple band-specific components of the superconducting condensate. Using the two-component Ginzburg-Landau model, we examine such vortex configurations in a two-band superconducting slab in parallel magnetic field. The fractional vortices appear due to the band-selective vortex penetration caused by different thresholds for vortex entry within each band-condensate, and stabilize near the edges of the sample. We show that the resulting fractional vortex configurations leave distinct fingerprints in the static measurements of the magnetization, as well as in ac dynamic measurements of the magnetic susceptibility, both of which can be readily used for the detection of these fascinating vortex states in several existing multiband superconductors. (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000346266000066 Publication Date 2014-12-09
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0003-6951;1077-3118; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.411 Times cited 22 Open Access
  Notes ; This work was supported by the Brazilian science agencies CAPES (Grant No. PNPD 223038.003145/2011-00), CNPq (Grant Nos. 307552/2012-8, 141911/2012-3, and APV-4 02937/2013-9), and FACEPE (Grant Nos. APQ-0202-1.05/10 and BCT-0278-1.05/ 11), the Research Foundation Flanders (FWO-Vlaanderen), and by the CNPq-FWO cooperation programme (CNPq Grant No. 490297/2009-9). D.D. acknowledges support from CONICET, CNEA, and ANPCyT-PICT2011-1537. The authors thank A. A. Shanenko for extensive discussions on the topic. ; Approved Most recent IF: 3.411; 2014 IF: 3.302
  Call Number UA @ lucian @ c:irua:122775 Serial 742
Permanent link to this record
 

 
Author Neek-Amal, M.; Peeters, F.M.
  Title Graphene on boron-nitride : Moiré pattern in the van der Waals energy Type A1 Journal article
  Year 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 104 Issue 4 Pages 041909-4
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract The spatial dependence of the van der Waals (vdW) energy between graphene and hexagonal boron-nitride (h-BN) is investigated using atomistic simulations. The van der Waals energy between graphene and h-BN shows a hexagonal superlattice structure identical to the observed Moire pattern in the local density of states, which depends on the lattice mismatch and misorientation angle between graphene and h-BN. Our results provide atomistic features of the weak van der Waals interaction between graphene and BN which are in agreement with experiment and provide an analytical expression for the size of the spatial variation of the weak van der Waals interaction. We also found that the A-B-lattice symmetry of graphene is broken along the armchair direction. (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000331209900028 Publication Date 2014-01-31
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0003-6951;1077-3118; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.411 Times cited 61 Open Access
  Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem Foundation of the Flemish Government. M.N.-A was supported by the EU-Marie Curie IIF postdoctoral Fellowship/299855. ; Approved Most recent IF: 3.411; 2014 IF: 3.302
  Call Number UA @ lucian @ c:irua:115802 Serial 1374
Permanent link to this record
 

 
Author Neek-Amal, M.; Peeters, F.M.
  Title Graphene on hexagonal lattice substrate : stress and pseudo-magnetic field Type A1 Journal article
  Year 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 104 Issue 17 Pages 173106
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Moire patterns in the pseudo-magnetic field and in the strain profile of graphene (GE) when put on top of a hexagonal lattice substrate are predicted from elasticity theory. The van der Waals interaction between GE and the substrate induces out-of-plane deformations in graphene which results in a strain field, and consequently in a pseudo-magnetic field. When the misorientation angle is about 0.5 degrees, a three-fold symmetric strain field is realized that results in a pseudo-magnetic field very similar to the one proposed by F. Guinea, M. I. Katsnelson, and A. K. Geim [Nature Phys. 6, 30 (2010)]. Our results show that the periodicity and length of the pseudo-magnetic field can be tuned in GE by changing the misorientation angle and substrate adhesion parameters and a considerable energy gap (23 meV) can be obtained due to out-of-plane deformation of graphene which is in the range of recent experimental measurements (20-30 meV). (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000336142500066 Publication Date 2014-05-02
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 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 ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem Foundation of the Flemish Government. M.N.-A. was supported by the EU-Marie Curie IIF postdoc Fellowship 299855. ; Approved Most recent IF: 3.411; 2014 IF: 3.302
  Call Number UA @ lucian @ c:irua:117724 Serial 1375
Permanent link to this record
 

 
Author Clima, S.; Wouters, D.J.; Adelmann, C.; Schenk, T.; Schroeder, U.; Jurczak, M.; Pourtois, G.
  Title Identification of the ferroelectric switching process and dopant-dependent switching properties in orthorhombic HfO2 : a first principles insight Type A1 Journal article
  Year 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
  Volume 104 Issue 9 Pages 092906
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
  Abstract The origin of the ferroelectric polarization switching in orthorhombic HfO2 has been investigated by first principles calculations. The phenomenon can be regarded as being the coordinated displacement of four O ions in the orthorhombic unit cell, which can lead to a saturated polarization as high as 53 mu C/cm(2). We show the correlation between the computed polarization reversal barrier and the experimental coercive fields. (C) 2014 AIP Publishing LLC.
  Address
  Corporate Author Thesis
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
  Language Wos 000332729200078 Publication Date 2014-03-06
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN (down) 0003-6951;1077-3118; ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 3.411 Times cited 79 Open Access
  Notes Approved Most recent IF: 3.411; 2014 IF: 3.302
  Call Number UA @ lucian @ c:irua:116873 Serial 1550
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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 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.
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  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 (down) 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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