“Hot magneto-phonon and electro-phonon resonances in heterostructures”. Peeters FM, Devreese JT, Semiconductor science and technology: B 7, 15 (1992). http://doi.org/10.1088/0268-1242/7/3B/004
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 2.19
Times cited: 12
DOI: 10.1088/0268-1242/7/3B/004
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“Novel nonlinear transport phenomena in a triangular quantum well”. Kastalsky A, Peeters FM, Chan WK, Florez LT, Harbison JP, Semiconductor science and technology: B 7, 530 (1992). http://doi.org/10.1088/0268-1242/7/3B/138
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.19
Times cited: 4
DOI: 10.1088/0268-1242/7/3B/138
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“Warm-electron transport in a two-dimensional semiconductor”. Xu W, Peeters FM, Devreese JT, Semiconductor science and technology 7, 1251 (1992)
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 2.19
Times cited: 3
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“Source/drain materials for Ge nMOS devices: phosphorus activation in epitaxial Si, Ge, Ge1-xSnx and SiyGe1-x-ySnx”. Vohra A, Makkonen I, Pourtois G, Slotte J, Porret C, Rosseel E, Khanam A, Tirrito M, Douhard B, Loo R, Vandervorst W, Ecs Journal Of Solid State Science And Technology 9, 044010 (2020). http://doi.org/10.1149/2162-8777/AB8D91
Abstract: This paper benchmarks various epitaxial growth schemes based on n-type group-IV materials as viable source/drain candidates for Ge nMOS devices. Si:P grown at low temperature on Ge, gives an active carrier concentration as high as 3.5 x 10(20) cm(-3) and a contact resistivity down to 7.5 x 10(-9) Omega.cm(2). However, Si:P growth is highly defective due to large lattice mismatch between Si and Ge. Within the material stacks assessed, one option for Ge nMOS source/drain stressors would be to stack Si:P, deposited at contact level, on top of a selectively grown n-SiyGe1-x-ySnx at source/drain level, in line with the concept of Si passivation of n-Ge surfaces to achieve low contact resistivities as reported in literature (Martens et al. 2011 Appl. Phys. Lett., 98, 013 504). The saturation in active carrier concentration with increasing P (or As)-doping is the major bottleneck in achieving low contact resistivities for as-grown Ge or SiyGe1-x-ySnx. We focus on understanding various dopant deactivation mechanisms in P-doped Ge and Ge1-xSnx alloys. First principles simulation results suggest that P deactivation in Ge and Ge1-xSnx can be explained both by P-clustering and donor-vacancy complexes. Positron annihilation spectroscopy analysis, suggests that dopant deactivation in P-doped Ge and Ge1-xSnx is primarily due to the formation of P-n-V and SnmPn-V clusters. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.2
DOI: 10.1149/2162-8777/AB8D91
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“Klein tunneling in single and multiple barriers in graphene”. Pereira JM, Peeters FM, Chaves A, Farias GA, Semiconductor science and technology 25, 033002 (2010). http://doi.org/10.1088/0268-1242/25/3/033002
Abstract: We review the transmission properties of carriers interacting with potential barriers in graphene. The tunneling of electrons and holes in quantum structures in graphene is found to display features that are in marked contrast with those of other systems. In particular, the interaction between the carriers with electrostatic potential barriers can be related to the propagation of electromagnetic waves in media with negative refraction indices, also known as metamaterials. This behavior becomes evident as one calculates the time evolution of wavepackets propagating across the barrier interface. In addition, we discuss the effect of trigonal warping on the tunneling through potential barriers.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.305
Times cited: 83
DOI: 10.1088/0268-1242/25/3/033002
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“Driven spin transitions in fluorinated single- and bilayer-graphene quantum dots”. Zebrowski DP, Peeters FM, Szafran B, Semiconductor science and technology 32, 065016 (2017). http://doi.org/10.1088/1361-6641/AA6DF4
Abstract: Spin transitions driven by a periodically varying electric potential in dilute fluorinated graphene quantum dots are investigated. Flakes of monolayer graphene as well as electrostatic electron traps induced in bilayer graphene are considered. The stationary states obtained within the tight-binding approach are used as the basis for description of the system dynamics. The dilute fluorination of the top layer lifts the valley degeneracy of the confined states and attenuates the orbital magnetic dipole moments due to current circulation within the flake. The spin-orbit coupling introduced by the surface deformation of the top layer induced by the adatoms allows the spin flips to be driven by the AC electric field. For the bilayer quantum dots the spin flip times is substantially shorter than the spin relaxation. Dynamical effects including many-photon and multilevel transitions are also discussed.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.305
DOI: 10.1088/1361-6641/AA6DF4
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“The reduction of the substitutional C content in annealed Si/SiGeC superlattices studied by dark-field electron holography”. Denneulin T, Rouvière JL, Béché, A, Py M, Barnes JP, Rochat N, Hartmann JM, Cooper D, Semiconductor science and technology 26, 1 (2011). http://doi.org/10.1088/0268-1242/26/12/125010
Abstract: Si/Si(1 − x − y)GexCy superlattices are used in the construction of new microelectronic architectures such as multichannel transistors. The introduction of carbon in SiGe allows for compensation of the strain and to avoid plastic relaxation. However, the formation of incoherent β-SiC clusters during annealing limits the processability of SiGeC. This precipitation leads to a modification of the strain in the alloy due to the reduction of the substitutional carbon content. Here, we investigated the strain in annealed Si/Si0.744Ge0.244C0.012 superlattices grown by reduced pressure chemical vapour deposition using dark-field electron holography. The variation of the substitutional C content was calculated by correlating the results with finite-element simulations. The obtained values were then compared with Fourier-transformed infrared spectrometry measurements. It was shown that after annealing for 2 min at 1050 °C carbon no longer has any influence on strain in the superlattice, which behaves like pure SiGe. However, a significant proportion of substitutional C atoms remain in a third-nearest neighbour (3nn) configuration. It was deduced that the influence of 3nn C on strain is negligible and that only isolated atoms have a significant contribution. It was also proposed that the 3nn configuration is an intermediary step during the formation of SiC clusters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.305
DOI: 10.1088/0268-1242/26/12/125010
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“Strain measurement in semiconductor FinFET devices using a novel moiré, demodulation technique”. Prabhakara V, Jannis D, Béché, A, Bender H, Verbeeck J, Semiconductor science and technology (2019). http://doi.org/10.1088/1361-6641/ab5da2
Abstract: Moiré fringes are used throughout a wide variety of applications in physics and
engineering to bring out small variations in an underlying lattice by comparing with another reference lattice. This method was recently demonstrated in Scanning Transmission Electron Microscopy imaging to provide local strain measurement in crystals by comparing the crystal lattice with the scanning raster that then serves as the reference. The images obtained in this way contain a beating fringe pattern with a local period that represents the deviation of the lattice from the reference. In order to obtain the actual strain value, a region containing a full period of the fringe is required, which results in a compromise between strain sensitivity and spatial resolution. In this paper we propose an advanced setup making use of an optimised scanning pattern and a novel phase stepping demodulation scheme. We demonstrate the novel method on a series of 16 nm Si-Ge semiconductor FinFET devices in which strain plays a crucial role in modulating the charge carrier mobility. The obtained results are compared with both Nano-beam diffraction and the recently proposed Bessel beam diffraction technique. The setup provides a much improved spatial resolution over conventional moiré imaging in STEM while at the same time being fast and requiring no specialised diffraction camera as opposed to the diffraction techniques we compare to.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.305
Times cited: 8
DOI: 10.1088/1361-6641/ab5da2
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“Critical assessment of the process of growth of a YBa2Cu3O7-\delta layer on Y2BaCuO5”. Jacques P, Verbist K, Lapin J, Ryelandt L, Van Tendeloo G, Delannay F, Superconductor science and technology 9, 176 (1996). http://doi.org/10.1088/0953-2048/9/3/008
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.325
Times cited: 1
DOI: 10.1088/0953-2048/9/3/008
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“Low- or high-angle Ar ion-beam etching to create ramp-type Josephson junctions”. Verbist K, Lebedev OI, Van Tendeloo G, Verhoeven MAJ, Rijnders AJHM, Blank DHA, Superconductor science and technology 9, 978 (1996). http://doi.org/10.1088/0953-2048/9/11/009
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.325
Times cited: 10
DOI: 10.1088/0953-2048/9/11/009
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“Structural properties of Zn-substituted epitaxial YBa2Cu3O7-\delta thin films”. Ye M, Schroeder J, Mehbod M, Deltour R, Naessens G, Duvigneaud PH, Verbist K, Van Tendeloo G, Superconductor science and technology 9, 543 (1996). http://doi.org/10.1088/0953-2048/9/7/006
Abstract: We optimized the deposition of YBa2(Cu1-xZnx)(3)O-7-delta thin-films using inverted cylindrical magnetron sputtering and report here a detailed structural study, especially in relation to crystal growth, associated surface morphology, Y2O3 precipitation and other secondary phases important for flux pinning. We find that the epitaxial quality of the Zn-substituted YBa2Cu3O7-delta films is decreased compared with high-quality pure YBa2Cu3O7-delta films prepared under identical conditions. The pure films have smoother surfaces, while those of Zn-substituted films contain pinholes and outgrowths. Secondary phases and a-axis grains were observed in the Zn-substituted films. Y2O3 precipitates with typical dimensions of 50-100 Angstrom have been found in both pure and Zn-substituted samples. However, their density of about 10(23) m(-3), observed in the pure films, is significantly reduced in the Zn-substituted films when increasing the Zn concentration up to 4%.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.325
Times cited: 7
DOI: 10.1088/0953-2048/9/7/006
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“The study of high Tc-superconducting materials by electron microscopy and electron diffraction”. Amelinckx S, Van Tendeloo G, van Landuyt J, Superconductor science and technology
T2 –, SATELLITE CONF TO THE 19TH INTERNATIONAL CONF ON LOW TEMPERATURE PHYSICS : HIGH TEMPERATURE SUPERCONDUCTIVITY, AUG 13-15, 1990, QUEENS COLL, CAMBRIDGE, ENGLAND 4, S19 (1991). http://doi.org/10.1088/0953-2048/4/1S/003
Abstract: A survey is given of the application of different electron microscopic techniques to the study of structural features of high T(c)-superconducting materials. Emphasis is laid in this contribution on those structural aspects for the study of which electron microscopy has been essential or has contributed to a significant extent.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.325
Times cited: 2
DOI: 10.1088/0953-2048/4/1S/003
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“Reporter gene-expressing bone marrow-derived stromal cells are immune-tolerated following implantation in the central nervous system of syngeneic immunocompetent mice”. Bergwerf I, de Vocht N, Tambuyzer B, Verschueren J, Reekmans K, Daans J, Ibrahimi A, Van Tendeloo V, Chatterjee S, Goossens H, Jorens PG, Baekelandt V, Ysebaert D, Van Marck E, Berneman ZN, Van Der Linden A, Ponsaerts P, BMC biotechnology (2009). http://doi.org/10.1186/1472-6750-9-1
Abstract: Background Cell transplantation is likely to become an important therapeutic tool for the treatment of various traumatic and ischemic injuries to the central nervous system (CNS). However, in many pre-clinical cell therapy studies, reporter gene-assisted imaging of cellular implants in the CNS and potential reporter gene and/or cell-based immunogenicity, still remain challenging research topics. Results In this study, we performed cell implantation experiments in the CNS of immunocompetent mice using autologous (syngeneic) luciferase-expressing bone marrow-derived stromal cells (BMSC-Luc) cultured from ROSA26-L-S-L-Luciferase transgenic mice, and BMSC-Luc genetically modified using a lentivirus encoding the enhanced green fluorescence protein (eGFP) and the puromycin resistance gene (Pac) (BMSC-Luc/eGFP/Pac). Both reporter gene-modified BMSC populations displayed high engraftment capacity in the CNS of immunocompetent mice, despite potential immunogenicity of introduced reporter proteins, as demonstrated by real-time bioluminescence imaging (BLI) and histological analysis at different time-points post-implantation. In contrast, both BMSC-Luc and BMSC-Luc/eGFP/Pac did not survive upon intramuscular cell implantation, as demonstrated by real-time BLI at different time-points post-implantation. In addition, ELISPOT analysis demonstrated the induction of IFN-ã-producing CD8+ T-cells upon intramuscular cell implantation, but not upon intracerebral cell implantation, indicating that BMSC-Luc and BMSC-Luc/eGFP/Pac are immune-tolerated in the CNS. However, in our experimental transplantation model, results also indicated that reporter gene-specific immune-reactive T-cell responses were not the main contributors to the immunological rejection of BMSC-Luc or BMSC-Luc/eGFP/Pac upon intramuscular cell implantation. Conclusion We here demonstrate that reporter gene-modified BMSC derived from ROSA26-L-S-L-Luciferase transgenic mice are immune-tolerated upon implantation in the CNS of syngeneic immunocompetent mice, providing a research model for studying survival and localisation of autologous BMSC implants in the CNS by real-time BLI and/or histological analysis in the absence of immunosuppressive therapy.
Keywords: A1 Journal article; Antwerp Surgical Training, Anatomy and Research Centre (ASTARC); Laboratory Experimental Medicine and Pediatrics (LEMP); Bio-Imaging lab; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.415
Times cited: 33
DOI: 10.1186/1472-6750-9-1
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“Microstructure and properties of oxygen controlled melt textured NdBaCuO superconductive ceramics”. Monot I, Tancret F, Laffez P, Van Tendeloo G, Desgardin G, Technology 65, 26 (1999). http://doi.org/10.1016/S0921-5107(99)00193-2
Abstract: Nd1+xBa2-xCu3O7-delta (123) bulk superconductors have been synthesised by the oxygen controlled melt growth method. Unlike the YBaCuO system, platinum doping or Nd4Ba2Cu2O10 (422) rich compositions do not refine the peritectic '422' secondary phase, but the latter improves the microstructural quality. Low oxygen partial pressure and high purity precursors are necessary to achieve in a reproducible manner high T-c and J(c) (up to 56 000 A/cm(2) in 0T and 30 000 A/cm(2) under 1.5T). The fishtail effect observed at 77 K is compared with the one observed in the YBCO system, and is discussed in terms of oxygen deficiency, Nd-Ba substitution, defects and vortex lattice. Our TEM observations did not evidence any Nd-Ba substituted clusters in the Nd123 matrix; however, some diffuse streaks, observed in the [100] zone ED pattern, support the fact that the source of the peak effect in this system is mainly due to oxygen disorder and low stability of the orthorhombic phase. (C) 1999 Elsevier Science S.A. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.552
Times cited: 5
DOI: 10.1016/S0921-5107(99)00193-2
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“Biaxially aligned titanium nitride thin films deposited by reactive unbalanced magnetron sputtering”. Mahieu S, Ghekiere P, de Winter G, de Gryse R, Depla D, Van Tendeloo G, Lebedev OI, Surface and coatings technology 200, 2764 (2006). http://doi.org/10.1016/j.surfcoat.2004.09.012
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.589
Times cited: 36
DOI: 10.1016/j.surfcoat.2004.09.012
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“Crystallographic aspects related to advanced tribological multilayers of Cr/CrN and Ti/TiN types produced by pulsed laser deposition (PLD)”. Major L, Morgiel J, Major B, Lackner JM, Waldhauser W, Ebner R, Nistor L, Van Tendeloo G, Surface and coatings technology 200, 6190 (2006). http://doi.org/10.1016/j.surfcoat.2005.11.021
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.589
Times cited: 32
DOI: 10.1016/j.surfcoat.2005.11.021
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“Macroscale computer simulations to investigate the chemical vapor deposition of thin metal-oxide films”. Neyts E, Bogaerts A, de Meyer M, van Gils S, Surface and coatings technology 201, 8838 (2007). http://doi.org/10.1016/j.surfcoat.2007.04.102
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.589
Times cited: 5
DOI: 10.1016/j.surfcoat.2007.04.102
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“Microstructure and defect characterization at interfaces in TiN/CrN multilayer coatings”. Major L, Tirry W, Van Tendeloo G, Surface and coatings technology 202, 6075 (2008). http://doi.org/10.1016/j.surfcoat.2008.07.005
Abstract: Microstructures of TiN/CrN multilayer coatings deposited on austenite steel (Cr Ni 18 8) by pulsed laser deposition (PLD) are characterized using transmission electron microscopy while their mechanical properties were assessed in a ball-on-disk test. All coatings have the same total thickness of about 1 ìm. The individual layers show a highly defective columnar structure, which is characterized by conventional electron microscopy (TEM) as well as by high resolution TEM. These techniques, combined with measurements of the local chemical composition through EDS prove that PLD allows to produce fully separated CrN and TiN layers. The friction, and consequently the wear, are lowered by increasing the total number of layers in the coating.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.589
Times cited: 23
DOI: 10.1016/j.surfcoat.2008.07.005
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“Modeling of gas discharge plasmas: What can we learn from it?”.Bogaerts A, de Bleecker K, Kolev I, Madani M, Surface and coatings technology 200, 62 (2005). http://doi.org/10.1016/j.surfcoat.2005.02.057
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.589
Times cited: 11
DOI: 10.1016/j.surfcoat.2005.02.057
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“Oscillating sliding wear of mono- and multilayer ceramic coatings in air”. Huq MZ, Celis JP, Meneve J, Stals L, Schryvers D, Surface and coatings technology 113, 242 (1999). http://doi.org/10.1016/S0257-8972(99)00009-2
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.589
Times cited: 10
DOI: 10.1016/S0257-8972(99)00009-2
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“Using the macroscopic scale to predict the nano-scale behavior of YSZ thin films”. Lamas JS, Leroy WP, Lu Y-G, Verbeeck J, Van Tendeloo G, Depla D, Surface and coatings technology 238, 45 (2014). http://doi.org/10.1016/j.surfcoat.2013.10.034
Abstract: In this work, Yttria-stabilized zirconia (YSZ) thin films were deposited using dual reactive magnetron sputtering. By varying the deposition conditions, the film morphology and texture of the thin films are tuned and biaxial alignment is obtained. Studying the crystallographic and microstructural properties of the YSZ thin films, a tilted columnar growth was identified. This tilt is shown to be dependent on the compositional gradient of the sample. The variation of composition within a single YSZ column measured via STEM-EDX is demonstrated to be equal to the macroscopic variation on a full YSZ sample when deposited under the same deposition parameters. A simple stress model was developed to predict the tilt of the growing columns. The results indicate that this model not only determines the column bending of the growing film but also confirms that a macroscopic approach is sufficient to determine the compositional gradient in a single column of the YSZ thin films. (C) 2013 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.589
Times cited: 8
DOI: 10.1016/j.surfcoat.2013.10.034
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“Oxidation barrier of Cu and Fe powder by Atomic Layer Deposition”. Cremers V, Rampelberg G, Barhoum A, Walters P, Claes N, Oliveira TM de, Assche GV, Bals S, Dendooven J, Detavernier C, Surface and coatings technology 349, 1032 (2018). http://doi.org/10.1016/j.surfcoat.2018.06.048
Abstract: Atomic layer deposition (ALD) is a vapor based technique which allows to deposit uniform, conformal films with a thickness control at the atomic scale. In this research, Al 2 O 3 coatings were deposited on micrometer-sized Fe and Cu powder (particles) using the thermal trimethylaluminum (TMA)/ water (H 2 O) process in a rotary pump-type ALD reactor. Rotation of the powder during deposition was required to obtain a pinhole-free ALD coating. The protective nature of the coating was evaluated by quantifying its effectiveness in protecting the metal particles during oxidative annealing treatments. The Al 2 O 3 coated powders were annealed in ambient air while in-situ thermogravimetric analysis (TGA) and in-situ x-ray diffraction (XRD) data were acquired. The thermal stability of a series of Cu and Fe powder with different Al 2 O 3 thicknesses were determined with TGA. In both samples a clear shift in oxidation temperature is visible. For Cu and Fe powder coated with 25 nm Al 2 O 3 , we observed an increase of the oxidation temperature with 300-400°C. For the Cu powder a thin film of only 8 nm is required to obtain an initial increase in oxidation temperature of 200°C. In contrast, for Fe powder a thicker coating of 25 nm is required. In both cases, the oxidation temperature increases with increasing thickness of the Al 2 O 3 coating. These results illustrate that the Al 2 O 3 thin film, deposited by the thermal ALD process (TMA/H 2 O) can be an efficient and pinhole-free barrier layer for micrometer-sized powder particles, provided that the powder is properly agitated during the process to ensure sufficient vapour-solid interaction.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.589
Times cited: 10
DOI: 10.1016/j.surfcoat.2018.06.048
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“Characterisation of a high-power impulse magnetron sputtered C/Mo/W wear resistant coating by transmission electron microscopy”. Sharp J, Mueller IC, Mandal P, Abbas A, Nord M, Doye A, Ehiasarian A, Hovsepian P, MacLaren I, Rainforth WM, Surface and coatings technology 377, 124853 (2019). http://doi.org/10.1016/J.SURFCOAT.2019.08.007
Abstract: Thin films of C/Mo/W deposited using combined UBM/HIPIMS sputtering show 2-8 nm clusters of material richer in Mo and W than the matrix (found by EDS microanalysis), with structures that resemble graphitic onions with the metal atoms arranged regularly within them. EELS microanalysis showed the clusters to be rich in W and Mo. As the time averaged power used in the pulsed HIPIMS magnetron was increased, the clusters became more defined, larger, and arranged into layers with amorphous matrix between them. Films deposited with average HIPIMS powers of 4 kW and 6 kW also showed a periodic modulation of the cluster density within the finer layers giving secondary, wider stripes in TEM. By analysing the ratio between the finer and coarser layers, it was found that this meta-layering is related to the substrate rotation in the deposition chamber but in a non-straightforward way. Reasons for this are proposed. The detailed structure of the clusters remains unknown and is the subject of further work. Fluctuation electron microscopy results indicated the presence of crystal planes with the graphite interlayer spacing, crystal planes in hexagonal WC perpendicular to the basal plane, and some plane spacings found in Mo2C. Other peaks in the FEM results suggested symmetry-related starting points for future determination of the structure of the clusters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.589
Times cited: 1
DOI: 10.1016/J.SURFCOAT.2019.08.007
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“Of enzyme use in cost-effective high solid simultaneous saccharification and fermentation processes”. Sóti V, Lenaerts S, Cornet I, Journal of biotechnology 270, 70 (2018). http://doi.org/10.1016/J.JBIOTEC.2018.01.020
Abstract: Enzyme cost is considered to be one of the most significant factors defining the final product price in lignocellulose hydrolysis and fermentation. Enzyme immobilization and recycling can be a tool to decrease costs. However, high solid loading is a key factor towards high product titers, and recovery of immobilized enzymes from this thick liquid is often overlooked. This paper aims to evaluate the economic feasibility of immobilized enzymes in simultaneous saccharification and fermentation (SSF) of lignocellulose biomass in general, as well as the recuperation of magnetic immobilized enzymes (m-CLEAs) during high solid loading in simultaneous saccharification, detoxification and fermentation processes (SSDF) of lignocellulose biomass. Enzyme prices were obtained from general cost estimations by Klein-Marcuschamer et al. [Klein-Marcuschamer et al. (2012) Biotechnol. Bioeng. 109, 10831087]. During enzyme cost analysis, the influence of inoculum recirculation as well as a shortened fermentation time was explored. Both resulted in 15% decrease of final enzyme product price. Enzyme recuperation was investigated experimentally and 99.5 m/m% of m-CLEAs was recovered from liquid medium in one step, while 88 m/m% could still be recycled from a thick liquid with high solid concentrations (SSF fermentation broth). A mathematical model was constructed to calculate the cost of immobilized and free enzyme utilization and showed that, with current process efficiencies and commercial enzyme prices, the cost reduction obtained by enzyme immobilization can reach around 60% compared to free enzyme utilization, while lower enzyme prices will result in a lower percentage of immobilization related savings, but overall enzyme costs will decrease significantly. These results are applied in a case study, estimating the viability of shifting from sugar to lignocellulose substrate for a 100 t lactic acid fermentation batch. It was concluded that it will only be economically feasible if the enzymes are produced at the most optimistic variable cost and either the activity of the immobilized catalyst or the recovery efficiency is further increased.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE)
Impact Factor: 2.599
Times cited: 6
DOI: 10.1016/J.JBIOTEC.2018.01.020
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“Evolution of the phase stability of NiAl under low energy ball milling”. Zelaya E, Esquivel MR, Schryvers D, Advanced powder technology 24, 1063 (2013). http://doi.org/10.1016/j.apt.2013.03.008
Abstract: Low energy mechanical alloying of Ni35 at.%Al and Ni40 at.%Al material was performed and the resulting structures were investigated by XRD and TEM. The final intermetallics observed consist of two phases, NiAl(B2) and Ni3Al while 7R and 3R martensite was observed in post-annealed samples. Different integrated milling times were associated to the intermetallic consolidation and initial blend dissociation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.659
Times cited: 10
DOI: 10.1016/j.apt.2013.03.008
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“Mechanical synthesis of high purity Cu-In-Se alloy nanopowder as precursor for printed CISe thin film solar cells”. Zaghi AE, Buffière M, Brammertz G, Batuk M, Lenaers N, Kniknie B, Hadermann J, Meuris M, Poortmans J, Vleugels J, Advanced powder technology 25, 1254 (2014). http://doi.org/10.1016/j.apt.2014.03.003
Abstract: Mechanical alloying and ball milling are low cost, up-scalable techniques for the preparation of high purity chalcogenide nanopowders to be used as precursor material for printing thin film solar cells. In this study, high purity copper indium selenium (Cu-In-Se) alloy nanopowders with 20-200 nm particle size were synthesized from macroscopic elemental Cu, In and Se powders via mechanical alloying and planetary ball milling. The particle size distribution, morphology, composition, and purity level of the synthesized Cu-In-Se alloy nanopowders were investigated. Thin Cu-In-Se alloy nanopowder ink coatings, deposited on Mo-coated glass substrates by doctor blading, were converted into a CuInSe2 semiconductor film by selenization heat treatment in Se vapor. The CuInSe2 film showed semiconducting band gap around 1 eV measured by photoluminescence spectroscopy. CuInSe2 absorber layer based thin film solar cell devices were fabricated to assess their performance. The solar cell device showed a total efficiency of 4.8%, as measured on 0.25 cm(2) area cell. (c) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.659
Times cited: 10
DOI: 10.1016/j.apt.2014.03.003
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“Solidelectrolyte interphase evolution of carbon-coated silicon nanoparticles for lithium-ion batteries monitored by transmission electron microscopy and impedance spectroscopy”. Van Havenbergh K, Turner S, Driesen K, Bridel J-S, Van Tendeloo G, Energy technology 3, 699 (2015). http://doi.org/10.1002/ente.201500034
Abstract: The main drawbacks of silicon as the most promising anode material for lithium-ion batteries (theoretical capacity=3572 mAh g−1) are lithiation-induced volume changes and the continuous formation of a solidelectrolyte interphase (SEI) upon cycling. A recent strategy is to focus on the influence of coatings and composite materials. To this end, the evolution of the SEI, as well as an applied carbon coating, on nanosilicon electrodes during the first electrochemical cycles is monitored. Two specific techniques are combined: Transmission Electron Microscopy (TEM) is used to study the surface evolution of the nanoparticles on a very local scale, whereas electrochemical impedance spectroscopy (EIS) provides information on the electrode level. A TEMEELS fingerprint signal of carbonate structures from the SEI is discovered, which can be used to differentiate between the SEI and a graphitic carbon matrix. Furthermore, the shielding effect of the carbon coating and the thickness evolution of the SEI are described.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.789
DOI: 10.1002/ente.201500034
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“Improving the Conversion and Energy Efficiency of Carbon Dioxide Splitting in a Zirconia-Packed Dielectric Barrier Discharge Reactor”. van Laer K, Bogaerts A, Energy technology 3, 1038 (2015). http://doi.org/10.1002/ente.201500127
Abstract: The use of plasma technology for CO2 splitting is gaining increasing interest, but one of the major obstacles to date for industrial implementation is the considerable energy cost. We demonstrate that the introduction of a packing of dielectric zirconia (ZrO2) beads into a dielectric barrier discharge (DBD) plasma reactor can enhance the CO2 conversion and energy efficiency up to a factor 1.9 and 2.2, respectively, compared to that in a normal (unpacked) DBD reactor. We obtained a maximum conversion of 42 % and a maximum energy efficiency of 9.6 %. However, it is the ability of the packing to almost double both the conversion and the energy efficiency simultaneously at certain input parameters that makes it very promising. The improved conversion and energy efficiency can be explained by the higher values of the local electric field and electron energy near the contact points of the beads and the lower breakdown voltage, demonstrated by 2 D fluid modeling.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.789
Times cited: 59
DOI: 10.1002/ente.201500127
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“The mechanical behavior during (de)lithiation of coated silicon nanoparticles as anode material for lithium-ion batteries studied by InSitu transmission electron microscopy”. Van Havenbergh K, Turner S, Marx N, Van Tendeloo G, Energy technology 4, 1005 (2016). http://doi.org/10.1002/ENTE.201600057
Abstract: One approach to cope with the continuous irreversible capacity loss in Si-based electrodes, attributed to lithiation-induced volume changes and the formation of a solid-electrolyte interface (SEI), is by coating silicon nanoparticles. A coating can improve the conductivity of the electrode, form a chemical shield against the electrolyte, or provide mechanical confinement to reduce the volume increase. The influence of such a coating on the mechanical behavior of silicon nanoparticles during Li insertion and Li extraction was investigated by insitu transmission electron microscopy. The type of coating was shown to influence the size of the unreacted core that remains after reaction of silicon with lithium. Furthermore, two mechanisms to relieve the stress generated during volume expansion are reported: the initiation of cracks and the formation of nanovoids. Both result in a full reaction of the silicon nanoparticles, whereas with the formation of cracks, additional surface area is created, on which an SEI can be formed.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.789
Times cited: 6
DOI: 10.1002/ENTE.201600057
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“Harvesting Renewable Energy for Carbon Dioxide Catalysis”. Navarrete A, Centi G, Bogaerts A, Mart?n?ngel, York A, Stefanidis GD, Energy technology 5, 796 (2017). http://doi.org/10.1002/ente.201600609
Abstract: The use of renewable energy (RE) to transform carbon dioxide into commodities (i.e., CO2 valorization) will pave the way towards a more sustainable economy in the coming years. But how can we efficiently use this energy (mostly available as electricity or solar light) to drive the necessary (catalytic) transformations? This paper presents a review of the technological advances in the transformation of carbon dioxide by means of RE. The socioeconomic implications and chemical basis of the transformation of carbon dioxide with RE are discussed. Then a general view of the use of RE to activate the (catalytic) transformations of carbon dioxide with microwaves, plasmas, and light is presented. The fundamental phenomena involved are introduced from a catalytic and reaction device perspective to present the advantages of this energy form as well as the inherent limitations of the present state-of-the-art. It is shown that efficient use of RE requires the redesign of current catalytic concepts. In this context, a new kind of reaction system, an energy-harvesting device, is proposed as a new conceptual approach for this endeavor. Finally, the challenges that lie ahead for the efficient and economical use of RE for carbon dioxide conversion are exposed.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.789
Times cited: 15
DOI: 10.1002/ente.201600609
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