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“A versatile plasma tool for the synthesis of carbon nanotubes and few-layer graphene sheets”. Malesevic A, Kemps R, Zhang L, Erni R, Van Tendeloo G, Vanhulsel A, van Haesendonck C, Journal of optoelectronics and advanced materials 10, 2052 (2008)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.449
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“Vortex-antivortex lattices in superconducting films with magnetic pinning arrays”. Milošević, MV, Peeters FM, Journal of low temperature physics 139, 257 (2005). http://doi.org/10.1007/s10909-005-3929-9
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.3
Times cited: 12
DOI: 10.1007/s10909-005-3929-9
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“Analytic solution of Ando's surface roughness model with finite domain distribution functions”. Moors K, Sorée B, Magnus W, 18th International Workshop On Computational Electronics (iwce 2015) (2015)
Abstract: Ando's surface roughness model is applied to metallic nanowires and extended beyond small roughness size and infinite barrier limit approximations for the wavefunction overlaps, such as the Prange-Nee approximation. Accurate and fast simulations can still be performed without invoking these overlap approximations by averaging over roughness profiles using finite domain distribution functions to obtain an analytic solution for the scattering rates. The simulations indicate that overlap approximations, while predicting a resistivity that agrees more or less with our novel approach, poorly estimate the underlying scattering rates. All methods show that a momentum gap between left- and right-moving electrons at the Fermi level, surpassing a critical momentum gap, gives rise to a substantial decrease in resistivity.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Glow discharge optical spectroscopy and mass spectrometry”. Bogaerts A John Wiley & Sons, Chichester, page 1 (2016).
Abstract: Atomic Spectroscopy Optical (atomic absorption spectroscopy, AAS; atomic emission spectroscopy, AES; atomic fluorescence spectroscopy, AFS; and optogalvanic spectroscopy) and mass spectrometric (magnetic sector, quadrupole mass analyzer, QMA; quadrupole ion trap, QIT; Fourier transform ion cyclotron resonance, FTICR; and time-of-flight, TOF) instrumentation are well suited for coupling to the glow discharge (GD). The GD is a relatively simple device. A potential gradient (500–1500 V) is applied between an anode and a cathode. In most cases, the sample is also the cathode. A noble gas (mostly Ar) is introduced into the discharge region before power initiation. When a potential is applied, electrons are accelerated toward the anode. As these electrons accelerate, they collide with gas atoms. A fraction of these collisions are of sufficient energy to remove an electron from a support gas atom, forming an ion. These ions are, in turn, accelerated toward the cathode. These ions impinge on the surface of the cathode, sputtering sample atoms from the surface. Sputtered atoms that do not redeposit on the surface diffuse into the excitation/ionization regions of the plasma where they can undergo excitation and/or ionization via a number of collisional processes, and the photons or ions created in this way can be detected with optical emission spectroscopy or mass spectrometry. GD sources offer a number of distinct advantages that make them well suited for specific types of analyses. These sources afford direct analysis of solid samples, thus minimizing the sample preparation required for analysis. The nature of the plasma also provides mutually exclusive atomization and excitation processes that help to minimize the matrix effects that plague so many other elemental techniques. In recent years, there is also increasing interest for using GD sources for liquid and gas analyses. In this article, first, the principles of operation of the GD plasma are reviewed, with an emphasis on how those principles relate to optical spectroscopy and mass spectrometry. Basic applications of the GD techniques are considered next. These include bulk analysis, surface analysis, and the analysis of solution and gaseous samples. The requirements necessary to obtain optical information are addressed following the analytical applications. This article focuses on the instrumentation needed to make optical measurements using the GD as an atomization/excitation source. Finally, mass spectrometric instrumentation and interfaces are addressed as they pertain to the use of a GD plasma as an ion source. GD sources provide analytically useful gas-phase species from solid samples. These sources can be interfaced with a variety of spectroscopic and spectrometric instruments for both quantitative and qualitative analyses.
Keywords: H1 Book chapter; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Modeling and tackling resistivity scaling in metal nanowires”. Moors K, Sorée B, Magnus W, International Conference on Simulation of Semiconductor Processes and Devices : [proceedings]
T2 –, International Conference on Simulation of Semiconductor Processes and, Devices (SISPAD), SEP 09-11, 2015, Washington, DC , 222 (2015)
Abstract: A self-consistent analytical solution of the multi-subband Boltzmann transport equation with collision term describing grain boundary and surface roughness scattering is presented to study the resistivity scaling in metal nanowires. The different scattering mechanisms and the influence of their statistical parameters are analyzed. Instead of a simple power law relating the height or width of a nanowire to its resistivity, the picture appears to be more complicated due to quantum-mechanical scattering and quantization effects, especially for surface roughness scattering.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Modeling of inter-ribbon tunneling in graphene”. Van de Put ML, Vandenberghe WG, Magnus W, Sorée B, Fischetti MV, 18th International Workshop On Computational Electronics (iwce 2015) (2015)
Abstract: The tunneling current between two crossed graphene ribbons is described invoking the empirical pseudopotential approximation and the Bardeen transfer Hamiltonian method. Results indicate that the density of states is the most important factor determining the tunneling current between small (similar to nm) ribbons. The quasi-one dimensional nature of graphene nanoribbons is shown to result in resonant tunneling.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“On improving accuracy of finite-element solutions of the effective-mass Schrodinger equation for interdiffused quantum wells and quantum wires”. Topalovic DB, Arsoski VV, Pavlovic S, Cukaric NA, Tadic MZ, Peeters FM, Communications in theoretical physics 65, 105 (2016)
Abstract: We use the Galerkin approach and the finite-element method to numerically solve the effective-mass Schrodinger equation. The accuracy of the solution is explored as it varies with the range of the numerical domain. The model potentials are those of interdiffused semiconductor quantum wells and axially symmetric quantum wires. Also, the model of a linear harmonic oscillator is considered for comparison reasons. It is demonstrated that the absolute error of the electron ground state energy level exhibits a minimum at a certain domain range, which is thus considered to be optimal. This range is found to depend on the number of mesh nodes N approximately as alpha(0) log(e)(alpha 1) (alpha N-2), where the values of the constants alpha(0), alpha(1), and alpha(2) are determined by fitting the numerical data. And the optimal range is found to be a weak function of the diffusion length. Moreover, it was demonstrated that a domain range adaptation to the optimal value leads to substantial improvement of accuracy of the solution of the Schrodinger equation.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.989
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“Process variability in Cu2ZnSnSe4 solar cell devices: Electrical and structural investigations”. Brammertz G, Buffiere M, Verbist C, Bekaert J, Batuk M, Hadermann J, et al, The conference record of the IEEE Photovoltaic Specialists Conference
T2 –, IEEE 42nd Photovoltaic Specialist Conference (PVSC), JUN 14-19, 2015, New Orleans, LA (2015)
Abstract: We have fabricated 9.7% efficient Cu2ZnSnSe4/CdS/ZnO solar cells by H2Se selenization of sequentially sputtered metal layers. Despite the good efficiency obtained, process control appears to be difficult. In the present contribution we compare the electrical and physical properties of two devices with nominal same fabrication procedure, but 1% and 9.7% power conversion efficiency respectively. We identify the problem of the lower performing device to be the segregation of ZnSe phases at the backside of the sample. This ZnSe seems to be the reason for the strong bias dependent photocurrent observed in the lower performing devices, as it adds a potential barrier for carrier collection. The reason for the different behavior of the two nominally same devices is not fully understood, but speculated to be related to sputtering variability.
Keywords: P1 Proceeding; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
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“What modeling reveals about the properties of an inductively coupled plasma”. Bogaerts A, Aghaei M, Spectroscopy 31, 52 (2016)
Abstract: To get better performance from inductively coupled plasma (ICP)-based methods, it is informative to study the properties of the ICP under different conditions. Annemie Bogaerts and Maryam Aghaei at the University of Antwerp, Belgium, are using computational modeling to examine how various properties of the ICP, such as gas flow path lines and velocity, temperature changes, and ionization effects, are affected by numerous factors, such as the gas flow rates of injector and auxiliary gas, applied power, and even the very presence of a mass spectrometry (MS) sampler. They have also applied their models to study particle transport through the ICP. Using their developed model, it is now possible to predict optimum conditions for specific analyses. Bogaerts and Aghaei spoke to us about this work.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 0.466
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“Glow discharge optical spectroscopy and mass spectrometry”. Bogaerts A, (2016). http://doi.org/10.1002/9780470027318.a5107
Abstract: Atomic Spectroscopy Optical (atomic absorption spectroscopy, AAS; atomic emission spectroscopy, AES; atomic fluorescence spectroscopy, AFS; and optogalvanic spectroscopy) and mass spectrometric (magnetic sector, quadrupole mass analyzer, QMA; quadrupole ion trap, QIT; Fourier transform ion cyclotron resonance, FTICR; and time-of-flight, TOF) instrumentation are well suited for coupling to the glow discharge (GD). The GD is a relatively simple device. A potential gradient (500–1500 V) is applied between an anode and a cathode. In most cases, the sample is also the cathode. A noble gas (mostly Ar) is introduced into the discharge region before power initiation. When a potential is applied, electrons are accelerated toward the anode. As these electrons accelerate, they collide with gas atoms. A fraction of these collisions are of sufficient energy to remove an electron from a support gas atom, forming an ion. These ions are, in turn, accelerated toward the cathode. These ions impinge on the surface of the cathode, sputtering sample atoms from the surface. Sputtered atoms that do not redeposit on the surface diffuse into the excitation/ionization regions of the plasma where they can undergo excitation and/or ionization via a number of collisional processes, and the photons or ions created in this way can be detected with optical emission spectroscopy or mass spectrometry. GD sources offer a number of distinct advantages that make them well suited for specific types of analyses. These sources afford direct analysis of solid samples, thus minimizing the sample preparation required for analysis. The nature of the plasma also provides mutually exclusive atomization and excitation processes that help to minimize the matrix effects that plague so many other elemental techniques. In recent years, there is also increasing interest for using GD sources for liquid and gas analyses. In this article, first, the principles of operation of the GD plasma are reviewed, with an emphasis on how those principles relate to optical spectroscopy and mass spectrometry. Basic applications of the GD techniques are considered next. These include bulk analysis, surface analysis, and the analysis of solution and gaseous samples. The requirements necessary to obtain optical information are addressed following the analytical applications. This article focuses on the instrumentation needed to make optical measurements using the GD as an atomization/excitation source. Finally, mass spectrometric instrumentation and interfaces are addressed as they pertain to the use of a GD plasma as an ion source. GD sources provide analytically useful gas-phase species from solid samples. These sources can be interfaced with a variety of spectroscopic and spectrometric instruments for both quantitative and qualitative analyses.
Keywords: A1 Journal article; PLASMANT
DOI: 10.1002/9780470027318.a5107
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“Non-uniform strain in lattice-mismatched heterostructure tunnel field-effect transistors”. Verreck D, Verhulst AS, Sorée B, Collaert N, Mocuta A, Thean A, Groeseneken G, Solid-State Device Research (ESSDERC), European Conference
T2 –, 46th European Solid-State Device Research Conference (ESSDERC) / 42nd, European Solid-State Circuits Conference (ESSCIRC), SEP 12-15, 2016, Lausanne, SWITZERLAND , 412 (2016)
Abstract: Because of its localized impact on the band structure, non-uniform strain at the heterojunction between lattice-mismatched materials has the potential to significantly enlarge the design space for tunnel-field effect transistors (TFET). However, the impact of a complex strain profile on TFET performance is difficult to predict. We have therefore developed a 2D quantum mechanical transport formalism capable of simulating the effects of a general non-uniform strain. We demonstrate the formalism for the GaAsxSb(1-x)/InyGa(1-y) As system and show that a performance improvement over a lattice-matched reference is indeed possible, allowing for relaxed requirements on the source doping. We also point out that the added design parameter of mismatch is not free, but limited by the desired effective bandgap at the tunnel junction.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Multi-level molecular modelling for plasma medicine”. Bogaerts A, Khosravian N, Van der Paal J, Verlackt CCW, Yusupov M, Kamaraj B, Neyts EC, Journal Of Physics D-Applied Physics 49, 054002 (2016)
Keywords: A1 Journal article; Plasma, laser ablation and surface modeling – Antwerp (PLASMANT)
Impact Factor: 2.588
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“Analysis and comparison of the co2 and co dielectric barrier discharge solid products”. Belov I, Paulussen S, Bogaerts A, Hakone Xv: International Symposium On High Pressure Low Temperature Plasma Chemistry: With Joint Cost Td1208 Workshop: Non-equilibrium Plasmas With Liquids For Water And Surface Treatment (2016)
Abstract: The CO and CO2 Dielectric Barrier Discharges (DBD) and their solid products were analyzed keeping similar energy input regimes. Gas chromatography analysis revealed the presence of CO2, CO and O-2 mixture in the exhaust of the CO2 DBD, while no O-2 was found when CO was used as a feed gas. It was shown that the C-2 Swan lines observed with optical emission spectroscopy were distinct in the CO plasma while they were not observed in the CO2 emission spectrum. Also the solid products of the plasmas exhibited remarkable differences. Nanoparticles with a diameter between10 and 300 nm, composed of Fe, O and C (Fe: O: C similar to 13: 50: 30) were produced by the CO2 DBD, while microscopic dendrite-like carbon structure (C: O similar to 73: 27) were formed in the CO plasma. The growth rate in the CO2 and CO DBDs was evaluated to be on the level of 0.15 mg/min and 15 mg/min, respectively. The difference of the CO and CO2 discharges and their products might be attributed to the oxygen content in the latter (6.4 mol.% O-2 in the exhaust) and subsequent etching of the carbonaceous film.
Keywords: P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Plasma based co2 conversion: a combined modeling and experimental study”. Bogaerts A, Snoeckx R, Berthelot A, Heijkers S, Wang W, Sun S, Van Laer K, Ramakers M, Michielsen I, Uytdenhouwen Y, Meynen V, Cool P, Hakone Xv: International Symposium On High Pressure Low Temperature Plasma Chemistry: With Joint Cost Td1208 Workshop: Non-equilibrium Plasmas With Liquids For Water And Surface Treatment (2016)
Abstract: In recent years there is increased interest in plasma-based CO2 conversion. Several plasma setups are being investigated for this purpose, but the most commonly used ones are a dielectric barrier discharge (DBD), a microwave (MW) plasma and a gliding arc (GA) reactor. In this proceedings paper, we will show results from our experiments in a (packed bed) DBD reactor and in a vortex-flow GA reactor, as well as from our model calculations for the detailed plasma chemistry in a DBD, MW and GA, for pure CO2 as well as mixtures of CO2 with N-2, CH4 and H2O.
Keywords: P1 Proceeding; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Nitrogen Fixation by Gliding Arc Plasma: Better Insight by Chemical Kinetics Modelling”. Wang W, Patil B, Heijkers S, Hessel V, Bogaerts A, Chemsuschem 10, 2110 (2017). http://doi.org/10.1002/cssc.201700611
Abstract: The conversion of atmospheric nitrogen into valuable compounds, that is, so-called nitrogen fixation, is gaining increased interest, owing to the essential role in the nitrogen cycle of the biosphere. Plasma technology, and more specifically gliding arc plasma, has great potential in this area, but little is known about the underlying mechanisms. Therefore, we developed a detailed chemical kinetics model for a pulsed-power gliding-arc reactor operating at atmospheric pressure for nitrogen oxide synthesis. Experiments are performed to validate the model and reasonable agreement is reached between the calculated and measured NO and NO2 yields and the corresponding energy efficiency for NOx formation for different N2/O2 ratios, indicating that the model can provide a realistic picture of the plasma chemistry. Therefore, we can use the model to investigate the reaction pathways for the formation and loss of NOx. The results indicate that vibrational excitation of N2 in the gliding arc contributes significantly to activating the N2 molecules, and leads to an energy efficient way of NOx production, compared to the thermal process. Based on the underlying chemistry, the model allows us to propose solutions on how to further improve the NOx formation by gliding arc technology. Although the energy efficiency of the gliding-arc-based nitrogen fixation process at the present stage is not comparable to the world-scale Haber–Bosch process, we believe our study helps us to come up with more realistic scenarios of entering a cutting-edge innovation in new business cases for the decentralised production of fertilisers for agriculture, in which lowtemperature plasma technology might play an important role.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 7.226
DOI: 10.1002/cssc.201700611
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“An analysis of the physiologic parameters of intraoral wear: a review”. Lawson NC, Janyavula S, Çakir D, Burgess JO, Journal Of Physics D-Applied Physics 46, Unsp 404007 (2013). http://doi.org/10.1088/0022-3727/46/40/404007
Abstract: This paper reviews the conditions of in vivo mastication and describes a novel method of measuring in vitro wear. Methods: parameters of intraoral wear are reviewed in this analysis, including chewing force, tooth sliding distance, food abrasivity, saliva lubrication, and antagonist properties. Results: clinical measurement of mastication forces indicates a range of normal forces between 20 and 140 N for a single molar. During the sliding phase of mastication, horizontal movement has been measured between 0.9 and 2.86 mm. In vivo wear occurs by three-body abrasion when food particles are interposed between teeth and by two-body abrasion after food clearance. Analysis of food particles used in wear testing reveals that food particles are softer than enamel and large enough to separate enamel and restoration surfaces and act as a solid lubricant. In two-body wear, saliva acts as a boundary lubricant with a viscosity of 3 cP. Enamel is the most relevant antagonist material for wear testing. The shape of a palatal cusp has been estimated as a 0.6 mm diameter ball and the hardest region of a tooth is its enamel surface. pH values and temperatures have been shown to range between 2-7 and 5-55 degrees C in intraoral fluids, respectively. These intraoral parameters have been used to modify the Alabama wear testing method.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.588
DOI: 10.1088/0022-3727/46/40/404007
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“Catheter-associated bloodstream infections in pediatric hematology-oncology patients”. Celebi S, Sezgin ME, Çakir D, Baytan B, Demirkaya M, Sevinir B, Bozdemir SE, Gunes AM, Hacimustafaoglu M, Pediatric Hematology And Oncology 30, 187 (2013). http://doi.org/10.3109/08880018.2013.772683
Abstract: Catheter-associated bloodstream infections (CABSIs) are common complications encountered with cancer treatment. The aims of this study were to analyze the factors associated with recurrent infection and catheter removal in pediatric hematology-oncology patients. All cases of CABSIs in patients attending the Department of Pediatric Hematology-Oncology between January 2008 and December 2010 were reviewed. A total of 44 episodes of CABSIs, including multiple episodes involving the same catheter, were identified in 31 children with cancer. The overall CABSIs rate was 7.4 infections per 1000 central venous catheter (CVC) days. The most frequent organism isolated was coagulase-negative Staphylococcus (CONS). The CVC was removed in nine (20.4%) episodes. We found that hypotension, persistent bacteremia, Candida infection, exit-side infection, neutropenia, and prolonged duration of neutropenia were the factors for catheter removal. There were 23 (52.2%) episodes of recurrence or reinfection. Mortality rate was found to be 9.6% in children with CABSIs. In this study, we found that CABSIs rate was 7.4 infections per 1000 catheter-days. CABSIs rates in our hematology-oncology patients are comparable to prior reports. Because CONS is the most common isolated microorganism in CABSIs, vancomycin can be considered part of the initial empirical regimen.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.12
DOI: 10.3109/08880018.2013.772683
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“RSV frequency in children below 2 years hospitalized for lower respiratory tract infections”. Hacimustafaoglu M, Celebi S, Bozdemir SE, Ozgur T, Ozcan I, Guray A, Çakir D, Turkish Journal Of Pediatrics 55, 130 (2013)
Abstract: Respiratory syncytial virus (RSV) is the most frequent agent of acute lower respiratory diseases and creates a significant burden of disease in children under 5 years all over the world. RSV causes severe lower respiratory tract infections (LRTI) that require hospitalization, especially in children <= 2 years. The aim of this study was to determine the incidence of RSV in children <= 2 years of age hospitalized for LRTI. Children <= 2 years of age hospitalized for one year for LRTI in the three largest hospitals of Bursa City Center, Turkey were evaluated. These three hospitals comprise 67.5% of all child beds in central Bursa, so this study allows us to evaluate the total disease burden and hospitalization incidence in central Bursa. Nasal swabs of the children were evaluated with RSV RespiStrip (Coris Bioconcept Organization). A total of 671 children were hospitalized for LRTI, and 254 (37.9%) had at least one hospitalization that was positive for RSV. Of all patients with LRTI, 54.8% (368/671) were hospitalized for acute bronchiolitis, while 45.2% (303/671) were hospitalized for pneumonia. Of patients with acute bronchiolitis or pneumonia, 41% (151/368) and 34% (103/303) were RSV+, respectively. Of RSV+ hospitalized children, 59.5% (151/254) were diagnosed as acute bronchiolitis and 40.5% (103/254) as pneumonia. The annual incidences of hospitalization due to LRTI, acute bronchiolitis and pneumonia were 20.5/1000, 11.2/1000 and 9.3/1000, respectively, in children <= 2 years of age. The annual incidences of hospitalization due to RSV+ LRTI, acute bronchiolitis and pneumonia were found as 7.8/1000, 4.6/1000 and 3.2/1000, respectively, in children <= 2 years of age. More than one-third of all children hospitalized with LRTI (38.3%, n=257) were in the 0-3 months age group. Compared to other age groups, RSV positivity was highest in that age group for acute bronchiolitis (57%), pneumonia (39.5%) and also total children with LRTI (47.9%). RSV is a very important cause of lower respiratory infections in children <= 2 years of age and occurred most frequently in those 0-3 months of age in our study. Since there is no other study assessing the annual hospitalization incidence of RSV+ LRTIs in one city in Turkey, our study has unique importance for providing valuable statistical data about RSV+ LRTIs.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.32
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“Direct nucleation of hexagonal boron nitride on diamond : crystalline properties of hBN nanowalls”. Hoang D-Q, Korneychuk S, Sankaran KJ, Pobedinskas P, Drijkoningen S, Turner S, Van Bael MK, Verbeeck J, Nicley SS, Haenen K, Acta materialia 127, 17 (2017). http://doi.org/10.1016/J.ACTAMAT2017.01.002
Abstract: Hexagonal boron nitride (hBN) nanowalls were deposited by unbalanced radio frequency sputtering on (100)-oriented silicon, nanocrystalline diamond films, and amorphous silicon nitride (Si3N4) membranes. The hBN nanowall structures were found to grow vertically with respect to the surface of all of the substrates. To provide further insight into the nucleation phase and possible lattice distortion of the deposited films, the structural properties of the different interfaces were characterized by transmission electron microscopy. For Si and Si3N4 substrates, turbostratic and amorphous BN phases form a clear transition zone between the substrate and the actual hBN phase of the bulk nanowalls. However, surprisingly, the presence of these phases was suppressed at the interface with a nanocrystalline diamond film, leading to a direct coupling of hBN with the diamond surface, independent of the vertical orientation of the diamond grain. To explain these observations, a growth mechanism is proposed in which the hydrogen terminated surface of the nanocrystalline diamond film leads to a rapid formation of the hBN phase during the initial stages of growth, contrary to the case of Si and Si3N4 substrates. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.301
DOI: 10.1016/J.ACTAMAT2017.01.002
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“Electron relaxation times and resistivity in metallic nanowires due to tilted grain boundary planes”. Moors K, Soree B, Tokei Z, Magnus W, On Ultimate Integration On Silicon (eurosoi-ulis) , 201 (2015)
Abstract: We calculate the resistivity contribution of tilted grain boundaries with varying parameters in sub-10nm diameter metallic nanowires. The results have been obtained with the Boltzmann transport equation and Fermi's golden rule, retrieving correct state-dependent relaxation times. The standard approximation schemes for the relaxation times are shown to fail when grain boundary tilt is considered. Grain boundaries tilted under the same angle or randomly tilted induce a resistivity decrease.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Perspective of tunnel-FET for future low-power technology nodes”. Verhulst AS, Verreck D, Smets Q, Kao K-H, Van de Put M, Rooyackers R, Sorée B, Vandooren A, De Meyer K, Groeseneken G, Heyns MM, Mocuta A, Collaert N, Thean AV-Y, 2014 Ieee International Electron Devices Meeting (iedm) (2014)
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Strain mapping for the silicon-on-insulator generation of semiconductor devices by high-angle annular dark field scanning electron transmission microscopy”. Cooper D, Le Royer C, Béché, A, Rouvière J-L, Applied Physics Letters 100, 233121 (2012). http://doi.org/10.1063/1.4723572
Abstract: The strain in pMOS p-type metal-oxide-semiconductor devicesgrown on silicon-on-insulator substrates has been measured by using the geometrical phase analysis of high angle annular dark field scanning electron microscopy. We show that by using the latest generations of electron microscopes, the strain can now be quantitatively measured with a large field of view, a spatial resolution as low as 1 nm with a sensitivity as good as 0.15%. This technique is extremely flexible, provides both structural and strain information, and can be applied to all types of nanoscale materials both quickly and easily.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
DOI: 10.1063/1.4723572
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“Ciliary white light generated during femtosecond laser ablation on transparent dielectrics”. Liu Y, Brelet Y, He Z, Yu L, Mitryukovskiy S, Houard A, Forestier B, Couairon A, Mysyrowicz A, 2013 Conference On And International Quantum Electronics Conference Lasers And Electro-optics Europe (cleo Europe/iqec) (2013)
Keywords: P1 Proceeding; Electron microscopy for materials research (EMAT)
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“Cobalt location in p-CoOxIn-SnO2 nanocomposites : correlation with gas sensor performances”. Vladimirova SA, Rumyantseva MN, Filatova DG, Chizhov AS, Khmelevsky NO, Konstantinova EA, Kozlovsky VF, Marchevsky AV, Karakulina OM, Hadermann J, Gaskov AM, Journal of alloys and compounds 721, 249 (2017). http://doi.org/10.1016/JJALLCOM.2017.05.332
Abstract: Nanocomposites CoOx/SnO2 based on tin oxide powders with different crystallinity have been prepared by wet chemical synthesis and characterized in detail by ICP-MS, XPS, EPR, XRD, HAADF-STEM imaging and EDX-STEM mapping. It was shown that cobalt is distributed differently between the bulk and surface of SnO2 nanocrystals, which depends on the crystallinity of the SnO2 matrix. The measurements of gas sensor properties have been carried out during exposure to CO (10 ppm), and H2S (2 ppm) in dry air. The decrease of sensor signal toward CO was attributed to high catalytic activity of Co3O4 leading to oxidation of carbon monoxide entirely on the surface of catalyst particles. The formation of a p-CoOx/n-SnO2 heterojunction results in high sensitivity of nanocomposites in H2S detection. The conductance significantly changed in the presence of H2S, which was attributed to the formation of metallic cobalt sulfide and removal of the p – n junction. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
DOI: 10.1016/JJALLCOM.2017.05.332
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“Influence of stress aging process on variants of nano-N4Ti3precipitates and martensitic transformation temperatures in NiTi shape memory alloy”. Radi A, Khalil-Allafi J, Etminanfar MR, Pourbabak S, Schryvers D, Amin-Ahmadi B, Materials &, design 262, 74 (2018). http://doi.org/10.1016/J.ELECTACTA.2018.01.024
Abstract: In this study, the effect of a stress aging process on the microstructure and martensitic phase transformation of NiTi shape memory alloy has been investigated. NiTi samples were aged at 450 degrees C for 1 h and 5 h under different levels of external tensile stress of 15, 60 and 150 MPa. Transmission electron microscopy (TEM) was used to characterize different variants and morphology of precipitates. The results show that application of all stress levels restricts the formation of precipitates variants in the microstructure after I h stress aging process. However, all variants can be detected by prolonging aging time to 5 h at 15 MPa stress level and the variants formation is again restricted by increasing the stress level. Moreover, the stress aging process resulted in changing the shape of precipitates in comparison with that of the stress-free aged samples. Coffee-bean shaped morphologies were detected for precipitates in all stress levels. According to the Differential Scanning Calorimetry (DSC) results, the martensite start temperature (M-s) on cooling shifts to higher temperatures with increasing the tensile stress during the aging process. This can be related to the change ofaustenite to martensite interface energy due to the different volume fractions and variants of precipitates. (c) 2018 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.364
DOI: 10.1016/J.ELECTACTA.2018.01.024
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“Self-assembly and clustering of magnetic peapod-like rods with tunable directional interaction”. Domingos JLC, Peeters FM, Ferreira WP, PLoS ONE 13, e0195552 (2018). http://doi.org/10.1371/JOURNLA.PONE.0195552
Abstract: Based on extensive Langevin Dynamics simulations we investigate the structural properties of a two-dimensional ensemble of magnetic rods with a peapod-like morphology, i.e, rods consisting of aligned single dipolar beads. Self-assembled configurations are studied for different directions of the dipole with respect to the rod axis. We found that with increasing misalignment of the dipole from the rod axis, the smaller the packing fraction at which the percolation transition is found. For the same density, the system exhibits different aggregation states for different misalignment. We also study the stability of the percolated structures with respect to temperature, which is found to be affected by the microstructure of the assembly of rods.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 2.806
DOI: 10.1371/JOURNLA.PONE.0195552
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“Self-consistent 30-band simulation approach for (non-)uniformly strained confined heterostructure tunnel field-effect transistors”. Verreck D, Verhulst AS, Van de Put ML, Sorée B, Magnus W, Collaert N, Mocuta A, Groeseneken G, Simulation of Semiconductor Processes and, Devices (SISPAD)AND DEVICES (SISPAD 2017) , 29 (2017)
Abstract: Heterostructures of III-V materials under a mechanical strain are being actively researched to enhance the performance of the tunnel field-effect transistor (TFET). In scaled III-V device structures, however, the interplay between the effects of strain and quantum confinement on the semiconductor band structure and hence the performance is highly non-trivial. We have therefore developed a computationally efficient quantum mechanical simulator Pharos, which enables self-consistent full-zone k.p-based simulations of III-V TFETs under a general non-uniform strain. We present the self-consistent procedure and demonstrate it on confined staggered bandgap GaAs0.5Sb0.5/In0.53Ga0.47As TFETs. We find a large performance degradation due to size-induced quantum confinement compared to non-confined devices. We show that some performance can be regained either by applying a uniform biaxial tensile strain or through the non-uniform strain profile at a lattice-mismatched heterostructure.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Impact of calibrated band-tails on the subthreshold swing of pocketed TFETs”. Bizindavyi J, Verhulst AS, Sorée B, Groeseneken G, Conference digest
T2 –, 76th Device Research Conference (DRC), JUN 24-27, 2018, Santa Barbara, CA (2018)
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Electron microscopy study of twinning in the Ni5Al3 bainitic phase”. Schryvers D, Ma Y, Toth L, Tanner L, TMS (1994)
Abstract: This contribution describes conventional and high resolution electron microscopy results on the different twinning arrangements in NisAl3 precipitates grown inside the B2 austenite phase. Short annealings introduce self-accommodating three-pointed star shaped precipitates consisting of twin related parts of different variants of the NisAl3 structure. Longer annealings result in plates growing separately from these wings and developing microtwinning in order to accommodate stress built-up at the interfaces with the surrounding matrix.
Keywords: A3 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
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“Electron microscopy study of twin sequences and branching in NissAl34 3R martensite”. Schryvers D, Van Landuyt J, ICOMAT (1992)
Abstract: Microtwin sequences in Ni66Al34 martensite plates of different size were investigated by electron microscopy. Although mostly irregular sequences were observed an average twin width w can be determined which increases with twin length L following the expected relation w ~ sqrt(L). High resolution electron microscopy was used to study the twin branching close to the plate boundaries and an atomic model for the branching of a microtwin and the changes in twin thickness is suggested
Keywords: A3 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
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