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“Electronic properties of hydrogenated silicene and germanene”. Houssa M, Scalise E, Sankaran K, Pourtois G, Afanas'ev VV, Stesmans A, Applied physics letters 98, 223107 (2011). http://doi.org/10.1063/1.3595682
Abstract: The electronic properties of hydrogenated silicene and germanene, so called silicane and germanane, respectively, are investigated using first-principles calculations based on density functional theory. Two different atomic configurations are found to be stable and energetically degenerate. Upon the adsorption of hydrogen, an energy gap opens in silicene and germanene. Their energy gaps are next computed using the HSE hybrid functional as well as the G(0)W(0) many-body perturbation method. These materials are found to be wide band-gap semiconductors, the type of gap in silicane (direct or indirect) depending on its atomic configuration. Germanane is predicted to be a direct-gap material, independent of its atomic configuration, with an average energy gap of about 3.2 eV, this material thus being potentially interesting for optoelectronic applications in the blue/violet spectral range. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3595682]
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 63
DOI: 10.1063/1.3595682
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“Electronic properties of two-dimensional hexagonal germanium”. Houssa M, Pourtois G, Afanas'ev VV, Stesmans A, Applied physics letters 96, 082111 (2010). http://doi.org/10.1063/1.3332588
Abstract: The electronic properties of two-dimensional hexagonal germanium, so called germanene, are investigated using first-principles simulations. Consistent with previous reports, the surface is predicted to have a poor metallic behavior, i.e., being metallic with a low density of states at the Fermi level. It is found that biaxial compressively strained germanene is a gapless semiconductor with linear energy dispersions near the K pointslike graphene. The calculated Fermi velocity of germanene is almost independent of the strain and is about 1.7×10<sup>6</sup> m/s, quite comparable to the value in graphene.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 86
DOI: 10.1063/1.3332588
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“Elucidating the asymmetric behavior of the discharge in a dual magnetron sputter deposition system”. Yusupov M, Bultinck E, Depla D, Bogaerts A, Applied physics letters 98, 131502 (2011). http://doi.org/10.1063/1.3574365
Abstract: A magnetron discharge is characterized by drifts of the charged particles guiding center, caused by the magnetic field, in contrast to unmagnetized discharges. Because of these drifts, a pronounced asymmetry of the discharge can be observed in a dual magnetron setup. In this work, it is found that the shape of the discharge in a dual magnetron configuration depends on the magnetic field configuration. In a closed configuration, strong drifts were observed in one preferential direction, whereas in a mirror configuration the deflection of the discharge was not so pronounced. Our calculations confirm experimental observations.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 4
DOI: 10.1063/1.3574365
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“First-principles modeling of intrinsic and extrinsic defects in \gamma-Al2O3”. Sankaran K, Pourtois G, Degraeve R, Zahid MB, Rignanese G-M, Van Houdt J, Applied physics letters 97, 212906 (2010). http://doi.org/10.1063/1.3507385
Abstract: The electronic properties of a set of intrinsic and extrinsic point defects in gamma-Al2O3 are investigated using quasiparticle calculations within the G(0)W(0) approximation. We find that the electronic signature of atomic vacancies lie deep in the band gap, close to the top of the valence band edge. The introduction of C, Si, and N impurities induces defective levels that are located close to the conduction band edge and near the middle of the band gap of the oxide. The comparison with electrical measurements reveals that the energy levels of some of these defects match with the electronic fingerprint of the defects reported in gamma-Al2O3 based nonvolatile memories. (C) 2010 American Institute of Physics. [doi:10.1063/1.3507385]
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 12
DOI: 10.1063/1.3507385
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“First-principles simulation of oxygen diffusion in HfOx : role in the resistive switching mechanism”. Clima S, Chen YY, Degraeve R, Mees M, Sankaran K, Govoreanu B, Jurczak M, De Gendt S, Pourtois G, Applied physics letters 100, 133102 (2012). http://doi.org/10.1063/1.3697690
Abstract: Transition metal oxide-based resistor random access memory (RRAM) takes advantage of oxygen-related defects in its principle of operation. Since the change in resistivity of the material is controlled by the oxygen deficiency level, it is of major importance to quantify the kinetics of the oxygen diffusion, key factor for oxide stoichiometry. Ab initio accelerated molecular dynamics techniques are employed to investigate the oxygen diffusivity in amorphous hafnia (HfOx, x = 1.97, 1.0, 0.5). The computed kinetics is in agreement with experimental measurements. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3697690]
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 63
DOI: 10.1063/1.3697690
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“Identification of the ferroelectric switching process and dopant-dependent switching properties in orthorhombic HfO2 : a first principles insight”. Clima S, Wouters DJ, Adelmann C, Schenk T, Schroeder U, Jurczak M, Pourtois G, Applied physics letters 104, 092906 (2014). http://doi.org/10.1063/1.4867975
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.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 79
DOI: 10.1063/1.4867975
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“Inelastic electron tunneling spectroscopy of HfO2 gate stacks : a study based on first-principles modeling”. Scalise E, Houssa M, Pourtois G, Afanas'ev VV, Stesmans A, Applied physics letters 99, 132101 (2011). http://doi.org/10.1063/1.3644158
Abstract: A first-principles modeling approach is used to investigate the vibrational properties of HfO2. The calculated phonon density of states is compared to experimental results obtained from inelastic electron tunneling spectroscopy (IETS) of various metal-oxide-semiconductor devices with HfO2 gate stacks. This comparison provides deep insights into the nature of the signatures of the complicated IETS spectra and provides valuable structural information about the gate stack, such as the possible presence of oxygen vacancies in jet-vapour deposited HfO2. Important structural differences between the interface of atomic-layer or molecular-beam deposited HfO2 and the Si substrate are also revealed.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 1
DOI: 10.1063/1.3644158
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“The influence of impurities on the performance of the dielectric barrier discharge”. Martens T, Bogaerts A, Brok WJM, van Dijk J, Applied physics letters 96, 091501 (2010). http://doi.org/10.1063/1.3327800
Abstract: In this letter, we investigate the effect of various levels of nitrogen impurity on the electrical performance of an atmospheric pressure dielectric barrier discharge in helium. We illustrate the different current profiles that are obtained, which exhibit one or more discharge pulses per half cycle and evaluate their performance in ionizing the discharge and dissipating the power. It is shown that flat and broad current profiles perform the best in ionizing the discharge and use the least amount of power per generated charged particle.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 28
DOI: 10.1063/1.3327800
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“Insights into Ni-filament formation in unipolar-switching Ni/HfO2/TiN resistive random access memory device”. Chen YY, Pourtois G, Adelmann C, Goux L, Govoreanu B, Degreave R, Jurczak M, Kittl JA, Groeseneken G, Wouters DJ, Applied physics letters 100, 113513 (2012). http://doi.org/10.1063/1.3695078
Abstract: In this letter, CMOS-compatible Ni/HfO2/TiN resistive random access memory stacks demonstrated attractive unipolar switching properties, showing >10(3) endurance and long retention at 150 degrees C. The Ni bottom electrode (BE) improved the switching yield over the NiSiPt BE. To better understand the unipolar forming mechanism, ab initio simulation and time of flight-secondary ion mass spectroscopy were utilized. Compared to the NiSiPt BE, Ni BE gives larger Ni diffusion in the HfO2 and lower formation enthalpy of Ni2+ species during electrical forming. Both the electrical and physical results supported a Ni-injection mechanism for the filament formation. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3695078]
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 29
DOI: 10.1063/1.3695078
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“Integrated atomistic chemical imaging and reactive force field molecular dynamic simulations on silicon oxidation”. Dumpala S, Broderick SR, Khalilov U, Neyts EC, van Duin ACT, Provine J, Howe RT, Rajan K, Applied physics letters 106, 011602 (2015). http://doi.org/10.1063/1.4905442
Abstract: In this paper, we quantitatively investigate with atom probe tomography, the effect of temperature on the interfacial transition layer suboxide species due to the thermal oxidation of silicon. The chemistry at the interface was measured with atomic scale resolution, and the changes in chemistry and intermixing at the interface were identified on a nanometer scale. We find an increase of suboxide (SiOx) concentration relative to SiO2 and increased oxygen ingress with elevated temperatures. Our experimental findings are in agreement with reactive force field molecular dynamics simulations. This work demonstrates the direct comparison between atom probe derived chemical profiles and atomistic-scale simulations for transitional interfacial layer of suboxides as a function of temperature.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 19
DOI: 10.1063/1.4905442
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“Modeling ultrashort laser-induced emission from a negatively biased metal”. Wendelen W, Mueller BY, Autrique D, Bogaerts A, Rethfeld B, Applied physics letters 103, 221603 (2013). http://doi.org/10.1063/1.4830378
Abstract: A theoretical study of ultrashort laser-induced electron emission from a negatively biased metallic cathode has been performed. Classical as well as tunneling electron emission mechanisms are considered. It was found that electron emission is governed by an interplay of processes inside as well as above the cathode. A hybrid model is proposed, where the electron distribution within the target is retrieved from Boltzmann scattering integrals, while the charge distribution above it is studied by a Particle-In-Cell simulation. The results indicate that non-equilibrium effects determine the initial emission process, whereas the space charge above the target suppresses the effectively emitted charge.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 8
DOI: 10.1063/1.4830378
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“Phase explosion in atmospheric pressure infrared laser ablation from water-rich targets”. Chen Z, Bogaerts A, Vertes A, Applied physics letters 89, 041503 (2006). http://doi.org/10.1063/1.2243961
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 32
DOI: 10.1063/1.2243961
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“Pulse shape influence on the atmospheric barrier discharge”. Martens T, Bogaerts A, van Dijk J, Applied physics letters 96, 131503 (2010). http://doi.org/10.1063/1.3315881
Abstract: In this letter we compare the effect of a radio-frequency sine, a low frequency sine, a rectangular and a pulsed dc voltage profile on the calculated electron production and power consumption in the dielectric barrier discharge. We also demonstrate using calculated potential distribution profiles of high time and space resolution how the pulsed dc discharge generates a secondary discharge pulse by deactivating the power supply.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 35
DOI: 10.1063/1.3315881
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“Revisiting the interplay between ablation, collisional, and radiative processes during ns-laser ablation”. Autrique D, Gornushkin I, Alexiades V, Chen Z, Bogaerts A, Rethfeld B, Applied physics letters 103, 174102 (2013). http://doi.org/10.1063/1.4826505
Abstract: A study of ns-laser ablation is presented, which focuses on the transient behavior of the physical processes that act in and above a copper sample. A dimensionless multiphase collisional radiative model describes the interplay between the ablation, collisional, and radiative mechanisms. Calculations are done for a 6 ns-Nd:YAG laser pulse operating at 532 nm and fluences up to 15 J/cm2. Temporal intensity profiles as well as transmissivities are in good agreement with experimental results. It is found that volumetric ablation mechanisms and photo-processes both play an essential role in the onset of ns-laser induced breakdown.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 13
DOI: 10.1063/1.4826505
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“Space charge limited electron emission from a Cu surface under ultrashort pulsed laser irradiation”. Wendelen W, Autrique D, Bogaerts A, Applied physics letters 96, 1 (2010). http://doi.org/10.1063/1.3292581
Abstract: In this theoretical study, the electron emission from a copper surface under ultrashort pulsed laser irradiation is investigated using a one-dimensional particle in cell model. Thermionic emission as well as multiphoton photoelectron emission were taken into account. The emitted electrons create a negative space charge above the target; consequently the generated electric field reduces the electron emission by several orders of magnitude. The simulations indicate that the space charge effect should be considered when investigating electron emission related phenomena in materials under ultrashort pulsed laser irradiation of metals.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 22
DOI: 10.1063/1.3292581
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“Structural and vibrational properties of amorphous GeO2 from first-principles”. Scalise E, Houssa M, Pourtois G, Afanas'ev VV, Stesmans A, Applied physics letters 98, 202110 (2011). http://doi.org/10.1063/1.3593036
Abstract: The structural and vibrational properties of amorphous germanium oxide (a-GeO<sub>2</sub>) are investigated using first-principles calculations based on density functional theory. We first generate an a-GeO<sub>2</sub> structure by first-principles molecular dynamics and analyze its structural properties. The vibrational spectra is then calculated within a density-functional approach. Both static and dynamic properties are in good agreement with experimental data. We next generate defects in our structure (oxygen vacancies with several density and charge states) and consider the most stable atomic configurations, focusing on the vibrational features of threefold coordinated O and divalent Ge centers.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 226
DOI: 10.1063/1.3593036
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“On the manifestation of phosphorus-vacancy complexes in epitaxial Si:P films”. Dhayalan SK, Kujala J, Slotte J, Pourtois G, Simoen E, Rosseel E, Hikavyy A, Shimura Y, Iacovo S, Stesmans A, Loo R, Vandervorst W;, Applied physics letters 108, 082106 (2016). http://doi.org/10.1063/1.4942605
Abstract: In situ doped epitaxial Si: P films with P concentrations > 1 x 10(21) at./cm(3) are suitable for source-drain stressors of n-FinFETs. These films combine the advantages of high conductivity derived from the high P doping with the creation of tensile strain in the Si channel. It has been suggested that the tensile strain developed in the Si: P films is due to the presence of local Si3P4 clusters, which however do not contribute to the electrical conductivity. During laser annealing, the Si3P4 clusters are expected to disperse resulting in an increased conductivity while the strain reduces slightly. However, the existence of Si3P4 is not proven. Based on first-principles simulations, we demonstrate that the formation of vacancy centered Si3P4 clusters, in the form of four P atoms bonded to a Si vacancy, is thermodynamically favorable at such high P concentrations. We suggest that during post epi-growth annealing, a fraction of the P atoms from these clusters are activated, while the remaining part goes into interstitial sites, thereby reducing strain. We corroborate our conjecture experimentally using positron annihilation spectroscopy, electron spin resonance, and Rutherford backscattering ion channeling studies. (C) 2016 AIP Publishing LLC.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 9
DOI: 10.1063/1.4942605
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“Origin of the performances degradation of two-dimensional-based metal-oxide-semiconductor field effect transistors in the sub-10 nm regime: A first-principles study”. Lu AKA, Pourtois G, Agarwal T, Afzalian A, Radu IP, Houssa M, Applied physics letters 108, 043504 (2016). http://doi.org/10.1063/1.4940685
Abstract: The impact of the scaling of the channel length on the performances of metal-oxide-semiconductor field effect transistors, based on two-dimensional (2D) channel materials, is theoretically investigated, using density functional theory combined with the non-equilibrium Green's function method. It is found that the scaling of the channel length below 10nm leads to strong device performance degradations. Our simulations reveal that this degradation is essentially due to the tunneling current flowing between the source and the drain in these aggressively scaled devices. It is shown that this electron tunneling process is modulated by the effective mass of the 2D channel material, and sets the limit of the scaling in future transistor designs. (C) 2016 AIP Publishing LLC.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 4
DOI: 10.1063/1.4940685
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“Mechanisms for plasma cryogenic etching of porous materials”. Zhang Q-Z, Tinck S, de Marneffe J-F, Zhang L, Bogaerts A, Applied physics letters 111, 173104 (2017). http://doi.org/10.1063/1.4999439
Abstract: Porous materials are commonly used in microelectronics, as they can meet the demand for continuously shrinking electronic feature dimensions. However, they are facing severe challenges in plasma etching, due to plasma induced damage. In this paper, we present both the plasma characteristics and surface processing during the etching of porous materials. We explain how the damage occurs in the porous material during plasma etching for a wide range of chuck temperatures and the responsible mechanism for plasma damage-free etching at cryogenic temperature, by a combination of experiments and numerical modeling.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 2
DOI: 10.1063/1.4999439
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“The role of UV photolysis and molecular transport in the generation of reactive species in a tissue model with a cold atmospheric pressure plasma jet”. Ghimire B, Szili EJ, Lamichhane P, Short RD, Lim JS, Attri P, Masur K, Weltmann K-D, Hong S-H, Choi EH, Applied physics letters 114, 093701 (2019). http://doi.org/10.1063/1.5086522
Abstract: Cold atmospheric pressure plasma jets (plasma) operated in ambient air provide a rich source of reactive oxygen and nitrogen species (RONS), which are known to influence biological processes important in disease. In the plasma treatment of diseased tissue such as subcutaneous cancer tumors, plasma RONS need to first traverse an interface between the plasma-skin surface and second be transported to millimeter depths in order to reach deep-seated diseased cells. However, the mechanisms in the plasma generation of RONS within soft tissues are not understood. In this study, we track the plasma jet delivery of RONS into a tissue model target and we delineate two processes: through target delivery of RONS generated (primarily) in the plasma jet and in situ RONS generation by UV photolysis within the target. We demonstrate that UV photolysis promotes the rapid generation of RONS in the tissue model target’s surface after which the RONS are transported to millimeter depths via a slower molecular process. Our results imply that the flux of UV photons from plasma jets is important for delivering RONS through seemingly impenetrable barriers such as skin. The findings have implications not only in treatments of living tissues but also in the functionalization of soft hydrated biomaterials such as hydrogels and extracellular matrix derived tissue scaffolds.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 12
DOI: 10.1063/1.5086522
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“Identifying alternative ferroelectric materials beyond Hf(Zr)O-₂”. Guo J, Clima S, Pourtois G, Van Houdt J, Applied Physics Letters 117, 262903 (2020). http://doi.org/10.1063/5.0028611
Abstract: A database-driven approach combined with ab initio density functional theory (DFT) simulations is used to identify and simulate alternative ferroelectric materials beyond Hf(Zr)O-2. The database-driven screening method identifies a class of wurtzite ferroelectric materials. DFT simulations of wurtzite magnesium chalcogenides, including MgS, MgSe, and MgTe, show their potential to achieve improved ferroelectric (FE) stability, simple atomistic unit cell structure, and large FE polarization. Strain engineering can effectively modulate the FE switching barrier height for facilitating FE switching. The effect of the piezoelectric property on the FE switching barrier heights is also examined.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4
DOI: 10.1063/5.0028611
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“Axial non-uniformity of longitudinal hollow cathode discharges for laser applications: numerical modeling and comparison with experiments”. Bogaerts A, Grozeva M, Applied physics: B: photo-physics and laser chemistry 75, 731 (2002). http://doi.org/10.1007/s00340-002-1039-9
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.696
Times cited: 8
DOI: 10.1007/s00340-002-1039-9
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“Effect of helium/argon gas ratio in a He-Ar-Cu+ IR hollow-cathode discharge laser : modeling study and comparison with experiments”. Bogaerts A, Grozeva M, Applied physics B : lasers and optics 76, 299 (2003). http://doi.org/10.1007/s00340-002-1093-3
Abstract: The He-Ar-Cu+ IR laser operates in a hollow-cathode discharge, typically in a mixture of helium with a few-% Ar. The population inversion of the Cu+ ion levels, responsible for laser action, is attributed to asymmetric charge transfer between He+ ions and sputtered Cu atoms. The Ar gas is added to promote sputtering of the Cu cathode. In this paper, a hybrid modeling network consisting of several different models for the various plasma species present in a He-Ar-Cu hollow-cathode discharge is applied to investigate the effect of Ar concentration in the gas mixture on the discharge behavior, and to find the optimum He/Ar gas ratio for laser operation. It is found that the densities of electrons, Ar+ ions, Ar-m* metastable atoms, sputtered Cu atoms and Cu+ ions increase upon the addition of more Ar gas, whereas the densities of He+ ions, He-2(+) ions and He-m* metastable atoms drop considerably. The product of the calculated Cu atom and He+ ion densities, which determines the production rate of the upper laser levels, and hence probably also the laser output power, is found to reach a maximum around 1-5% Ar addition. This calculation result is compared to experimental measurements, and reasonable agreement has been reached.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.696
Times cited: 6
DOI: 10.1007/s00340-002-1093-3
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“Interpretation of TOF-SIMS depth profiles from ultrashallow high-k dielectric stacks assisted by hybrid collisional computer simulation”. Ignatova VA, Möller W, Conard T, Vandervorst W, Gijbels R, Applied physics A : materials science &, processing 81, 71 (2005). http://doi.org/10.1007/s00339-005-3239-8
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.455
Times cited: 4
DOI: 10.1007/s00339-005-3239-8
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“Hydrogeochemical exploration for gold in the Osilo area, Sardinia, Italy”. Cidu R, Fanfani L, Shand P, Edmunds WM, Van 't dack L, Gijbels R, Applied geochemistry 10, 517 (1995). http://doi.org/10.1016/0883-2927(95)00022-4
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.268
Times cited: 10
DOI: 10.1016/0883-2927(95)00022-4
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“Sulfur species and associated trace elements in south-west Bulgarian thermal waters”. Veldeman E, Van 't dack L, Gijbels R, Pentcheva E, Applied geochemistry 6, 49 (1991)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.268
Times cited: 7
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“Efficient amorphous platinum catalyst cluster growth on porous carbon : a combined molecular dynamics and experimental study”. Xie L, Brault P, Coutanceau C, Bauchire J-M, Caillard A, Baranton S, Berndt J, Neyts EC, Applied catalysis : B : environmental 162, 21 (2015). http://doi.org/10.1016/j.apcatb.2014.06.032
Abstract: Amorphous platinum clusters supported on porous carbon have been envisaged for high-performance fuel cell electrodes. For this application, it is crucial to control the morphology of the Pt layer and the Ptsubstrate interaction to maximize activity and stability. We thus investigate the morphology evolution during Pt cluster growth on a porous carbon substrate employing atomic scale molecular dynamics simulations. The simulations are based on the Pt-C interaction potential using parameters derived from density functional theory and are found to yield a Pt cluster morphology similar to that observed in low loaded fuel cell electrodes prepared by plasma sputtering. Moreover, the simulations show amorphous Pt cluster growth in agreement with X-ray diffraction and transmission electron microscopy experiments on high performance low Pt content (10 μgPt cm−2) loaded fuel cell electrodes and provide a fundamental insight in the cluster growth mechanism.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 9.446
Times cited: 20
DOI: 10.1016/j.apcatb.2014.06.032
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“Interactions of plasma species on nickel catalysts : a reactive molecular dynamics study on the influence of temperature and surface structure”. Somers W, Bogaerts A, van Duin ACT, Neyts EC, Applied catalysis : B : environmental 154, 1 (2014). http://doi.org/10.1016/j.apcatb.2014.01.061
Abstract: Methane reforming by plasma catalysis is a complex process that is far from understood. It requires a multidisciplinary approach which ideally takes into account all effects from the plasma on the catalyst, and vice versa. In this contribution, we focus on the interactions of CHx (x = {1,2,3}) radicals that are created in the plasma with several nickel catalyst surfaces. To this end, we perform reactive molecular dynamics simulations, based on the ReaxFF potential, in a wide temperature range of 4001600 K. First, we focus on the H2 formation as a function of temperature and surface structure. We observe that substantial H2 formation is obtained at 1400 K and above, while the role of the surface structure seems limited. Indeed, in the initial stage, the type of nickel surface influences the CH bond breaking efficiency of adsorbed radicals; however, the continuous carbon diffusion into the surface gradually diminishes the surface crystallinity and therefore reduces the effect of surface structure on the H2 formation probability. Furthermore, we have also investigated to what extent the species adsorbed on the catalyst surface can participate in surface reactions more in general, for the various surface structures and as a function of temperature. These results are part of the ongoing research on the methane reforming by plasma catalysis, a highly interesting yet complex alternative to conventional reforming processes.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 9.446
Times cited: 23
DOI: 10.1016/j.apcatb.2014.01.061
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“Can plasma be formed in catalyst pores? A modeling investigation”. Zhang Y-R, Van Laer K, Neyts EC, Bogaerts A, Applied catalysis : B : environmental 185, 56 (2016). http://doi.org/10.1016/j.apcatb.2015.12.009
Abstract: tWe investigate microdischarge formation inside catalyst pores by a two-dimensional fluid model forvarious pore sizes in the m-range and for various applied voltages. Indeed, this is a poorly understoodphenomenon in plasma catalysis. The calculations are performed for a dielectric barrier discharge inhelium, at atmospheric pressure. The electron and ion densities, electron temperature, electric field andpotential, as well as the electron impact ionization and excitation rate and the densities of excited plasmaspecies, are examined for a better understanding of the characteristics of the plasma inside a pore. Theresults indicate that the pore size and the applied voltage are critical parameters for the formation of amicrodischarge inside a pore. At an applied voltage of 20 kV, our calculations reveal that the ionizationmainly takes place inside the pore, and the electron density shows a significant increase near and inthe pore for pore sizes larger than 200m, whereas the effect of the pore on the total ion density isevident even for 10m pores. When the pore size is fixed at 30m, the presence of the pore has nosignificant influence on the plasma properties at an applied voltage of 2 kV. Upon increasing the voltage,the ionization process is enhanced due to the strong electric field and high electron temperature, andthe ion density shows a remarkable increase near and in the pore for voltages above 10 kV. These resultsindicate that the plasma species can be formed inside pores of structured catalysts (in the m range),and they may interact with the catalyst surface, and affect the plasma catalytic process.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 9.446
Times cited: 75
DOI: 10.1016/j.apcatb.2015.12.009
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“DFT study of Ni-catalyzed plasma dry reforming of methane”. Shirazi M, Neyts EC, Bogaerts A, Applied catalysis : B : environmental 205, 605 (2017). http://doi.org/10.1016/j.apcatb.2017.01.004
Abstract: tWe investigated the plasma-assisted catalytic reactions for the production of value-added chemicalsfrom Ni-catalyzed plasma dry reforming of methane by means of density functional theory (DFT). Weinspected many activation barriers, from the early stage of adsorption of the major chemical fragmentsderived fromCH4andCO2molecules up to the formation of value-added chemicals at the surface, focusingon the formation of methanol, as well as the hydrogenation of C1and C2hydrocarbon fragments. Theactivation barrier calculations show that the presence of surface-bound H atoms and in some cases alsoremaining chemical fragments at the surface facilitates the formation of products. This implies that thehydrogenation of a chemical fragment on the hydrogenated crystalline surface is energetically favouredcompared to the simple hydrogenation of the chemical fragment at the bare Ni(111) surface. Indeed, thepresence of hydrogen modifies the electronic structure of the surface and the course of the reactions.We therefore conclude that surface-bound H atoms, and to some extent also the remaining chemicalfragments at the crystalline surface, induce the following effects: they facilitate associative desorption ofmethanol and ethane by increasing the rate of H-transfer to the adsorbed fragments while they impedehydrogenation of ethylene to ethane, thus promoting again the desorption of ethylene. Overall, they thusfacilitate the catalytic conversion of the formed fragments from CH4and CO2, into value-added chemicals.Finally, we believe that the retention of methane fragments, especially CH3, in the presence of surface-boundHatoms (as observed here for Ni) can be regarded as an identifier for the proper choice of a catalystfor the production of value-added chemicals.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 9.446
Times cited: 26
DOI: 10.1016/j.apcatb.2017.01.004
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