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“A counterion-catalyzed (S0H+)(X-I+) pathway toward heat- and steam-stable mesostructured silica assembled from amines in acidic conditions”. Cassiers K, van der Voort P, Linssen T, Vansant EF, Lebedev O, van Landuyt J, The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical 107, 3690 (2003). http://doi.org/10.1021/jp026696v
Abstract: An alternative pathway to assemble mesoporous molecular sieve silicas is developed using nonionic alkylamines and N,N-dimethylalkylamines (SO) as structure-directing agents in acidic conditions. The synthesized mesostructures possess wormhole-like frameworks with pore sizes and pore volumes in the range of 20-90 Angstrom and 0.5-1.3 cm(3)/g, respectively. The formation of the mesophase is controlled by a counterion-mediated mechanism of the type (S(0)H(+))(X(-)I(+)), where S(0)H(+) are protonated water molecules that are hydrogen bonded to the lone electron pairs on the amine surfactant headgroups (S(0)H(+)), X(-) is the counteranion originating from the acid, and I(+) are the positively charged (protonated) silicate species. We found that the stronger the ion X(-) is bonded to S(0)H(+), the more it catalyzes the silica condensation into (S(0)H(+))(X(-)I(+)). Br(-) is shown to be a strong binding anion and therefore a fast silica polymerization promoter compared to Cl(-) resulting in the formation of a higher quality mesophase for the Br(-) syntheses. We also showed that the polymerization rate of the silica, dictated by the counterion, controls the morphology of the mesostructures from nonuniform agglomerated blocks in the case of Br(-) syntheses to spherical particles for the Cl(-) syntheses. Next to many benefits such as low temperature, short synthesis time, and the use of inexpensive, nontoxic, and easily extractable amine templates, the developed materials have a remarkable higher thermal and hydrothermal stability compared to hexagonal mesoporous silica, which is also prepared with nonionic amines but formed through the S(0)I(0) mechanism.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.177
Times cited: 9
DOI: 10.1021/jp026696v
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“A new iron oxophosphate SrFe3(PO4)3O with chain-like structure”. Morozov VA, Pokholok KV, Lazoryak BI, Malakho AP, Lachgar A, Lebedev OI, Van Tendeloo G, Journal of solid state chemistry 170, 411 (2003). http://doi.org/10.1016/S0022-4596(02)00133-0
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 12
DOI: 10.1016/S0022-4596(02)00133-0
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“A new structure type of the ternary sulfide Eu1.3Nb1.9S5”. Khasanova NR, Van Tendeloo G, Lebedev OI, Amelinckx S, Grippa AY, Abakumov AM, Istomin SY, D'yachenko OG, Antipov EV, Journal of solid state chemistry 164, 345 (2002). http://doi.org/10.1006/jssc.2001.9501
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 2
DOI: 10.1006/jssc.2001.9501
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“A novel approach to analyse FTIR spectra of precipitates in boron-doped silicon”. de Gryse O, Vanhellemont J, Clauws P, Lebedev O, van Landuyt J, Simoen E, Claeys C, Physica: B : condensed matter
T2 –, 22nd International Conference on Defects in Semiconductors (ICDS-22), JUL 28-AUG 01, 2003, UNIV AARHUS, AARHUS, DENMARK 340, 1013 (2003). http://doi.org/10.1016/j.physb.2003.09.194
Abstract: Infrared absorption spectra of composite precipitates are analysed with a modified Day-Thorpe algorithm, assuming a precipitated phase consisting of a mixture of two components with known optical properties. Additional constraints are introduced when solving the model equations by using a priori knowledge making the algorithm more reliable. It is shown that this novel approach allows determining both morphology and composition of precipitates. The method is applied to characterise oxide precipitates in boron-doped silicon. The results indicate that for the resistivity range above 60 mOmegacm, the precipitated phase is most probably SiO1.17+/-0.14, while for resistivities below 20 mOmega cm, precipitates consist of a SiO2/B2O3 composite with a large volume fraction of B(2)0(3) (up to 40% for 8 mOmegacm material). (C) 2003 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.386
Times cited: 4
DOI: 10.1016/j.physb.2003.09.194
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“A potential method to correlate electrical properties and microstructure of a unique high-Tc superconducting Josephson junction”. Verbist K, Lebedev OI, Van Tendeloo G, Tafuri F, Granozio FM, Di Chiara A, Bender H, Applied physics letters 74, 1024 (1999). http://doi.org/10.1063/1.123443
Abstract: A method to correlate microstructure from cross-section transmission electron microscopy (TEM) investigations and transport properties of a single well characterized high-T-c artificial grain boundary junction is reported. A YBa2Cu3O7-delta 45 degrees twist junction exhibiting the typical phenomenology of high T-c Josephson weak links was employed. The TEM sample preparation is based on focused ion beam etching and allows to easily localize the electron transparent area on a microbridge. The reported technique opens clear perspectives in the determination of the microstructural origin of variations in Josephson junction properties, such as the spread in I-c and IcRN values and the presence of different transport regimes in nominally identical junctions. (C) 1999 American Institute of Physics. [S0003-6951(99)03404-X].
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 5
DOI: 10.1063/1.123443
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“A study of the domain structure of epitaxial (La-Ca)MnO3 films by high-resolution transmission electron microscopy”. Lebedev OI, Van Tendeloo G, Abakumov AM, Amelinckx S, Leibold B, Habermeier H-U, Philosophical magazine: A: physics of condensed matter: defects and mechanical properties 79, 1461 (1999). http://doi.org/10.1080/01418619908210372
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 27
DOI: 10.1080/01418619908210372
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“A-site ordering and stripe phases in manganite films”. Sudheendra L, Moshnyaga V, Lebedev OI, Gehrke K, Belenciuc A, Shapoval O, Van Tendeloo G, Samwer K, Physica: B : condensed matter
T2 –, International Conference on Strongly Correlated Electron Systems (SCES, 2007), MAY 13-18, 2007, Houston, TX 403, 1645 (2008). http://doi.org/10.1016/j.physb.2007.10.332
Abstract: Insulating and metallic stripes above and below the Curie temperature, T-C, respectively, were observed by a high-resolution scanning tunneling microscopy (STM) and/or spectroscopy (STS) in A-site ordered and macroscopically strain free epitaxial La0.75Ca0.25MnO3 film grown on MgO substrate. The “insulating” stripes were found to be incommensurable to the lattice and aligned along (110) direction. Metallic stripes were commensurable with periodicity 2a(p)similar to 0.8 nm and aligned parallel to the crystallographic a/b-axis. Formation of these stripes involves competing charge, orbital, and lattice orders and is an outcome of an overlapping of electron wave functions mediated by the local lattice-strain distribution, existed even in A-site ordered film due to the difference in cation radii of La and Ca. (C) 2007 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.386
DOI: 10.1016/j.physb.2007.10.332
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“A-site ordering versus electronic inhomogeneity in colossally magnetoresistive manganite films”. Moshnyaga V, Sudheendra L, Lebedev OI, Koster SA, Gehrke K, Shapoval O, Belenchuk A, Damaschke B, Van Tendeloo G, Samwer K, Physical review letters 97, 107205 (2006). http://doi.org/10.1103/PhysRevLett.97.107205
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.462
Times cited: 43
DOI: 10.1103/PhysRevLett.97.107205
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“Accurate measurements of atomic displacements in La0.9Sr0.1MnO3 thin films grown on a SrTiO3 substrate”. Geuens P, Lebedev OI, van Dyck D, Van Tendeloo G s.l., page 1133 (2000).
Keywords: H3 Book chapter; Electron microscopy for materials research (EMAT); Vision lab
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“Aluminum incorporation into MCM-48 toward the creation of Brønsted acidity”. Collart O, Cool P, van der Voort P, Meynen V, Vansant EF, Houthoofd KJ, Grobet PJ, Lebedev OI, Van Tendeloo G, The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical 108, 13905 (2004). http://doi.org/10.1021/jp049837x
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.177
Times cited: 13
DOI: 10.1021/jp049837x
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“An effective morphology control of hydroxyapatite crystals via hydrothermal synthesis”. Neira IS, Kolen'ko YV, Lebedev OI, Van Tendeloo G, Gupta HS, Guitián F, Yoshimura M, Crystal growth &, design 9, 466 (2009). http://doi.org/10.1021/cg800738a
Abstract: A facile urea-assisted hydrothermal synthesis and systematic characterization of hydroxyapatite (HA) with calcium nitrate tetrahydrate and diammonium hydrogen phosphate as precursors are reported. The advantage of the proposed technique over previously reported synthetic approaches is the simple but precise control of the HA crystals morphology, which is achieved by employing an intensive, stepwise, and slow thermal decomposition of urea as well as varying initial concentrations of starting reagents. Whereas the plate-, hexagonal prism- and needle-like HA particles preferentially growth along the c-axis, the smaller and fine-plate-like HA crystals demonstrate crystal growth along the (102) and (211) directions, uncommon for HA. Furthermore, it was established that the hydrothermally derived powdered products are phase-pure HA containing CO32− anions in the crystal lattice, that is, AB-type carbonated hydroxyapatite. Transmission electron microscopy (TEM) and electron diffraction (ED) of selected samples reveal that the as-prepared HA crystals are single-crystalline and exhibit a nearly defect-free microstructure. The hardness and elastic modulus of the hexagonal prism-like HA crystals have been investigated on a nanoscale using the nanoindentation technique; the observed trends are discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.055
Times cited: 183
DOI: 10.1021/cg800738a
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“Anion ordering and defect structure in Ruddlesden-Popper strontium niobium oxynitrides”. Tobías G, Beltrán-Porter D, Lebedev OI, Van Tendeloo G, Rodríguez-Carvajal J, Fuertes A, Inorganic chemistry 43, 8010 (2004). http://doi.org/10.1021/ic049236k
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 31
DOI: 10.1021/ic049236k
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“Antiferroelectric phase transition in Sr9In(PO4)7”. Stefanovich SY, Belik AA, Azuma M, Takano M, Baryshnikova OV, Morozov VA, Lazoryak BI, Lebedev OI, Van Tendeloo G, Physical review : B : condensed matter and materials physics 70, 172103 (2004). http://doi.org/10.1103/PhysRevB.70.172103
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 17
DOI: 10.1103/PhysRevB.70.172103
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“Atomic and microstructure of CMR materials”. Van Tendeloo G, Lebedev OI, Amelinckx S, Journal of magnetism and magnetic materials 211, 73 (2000). http://doi.org/10.1016/S0304-8853(99)00716-7
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.63
Times cited: 48
DOI: 10.1016/S0304-8853(99)00716-7
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“Au-manganese oxide nanostructures by a plasma-assisted process as electrocatalysts for oxygen evolution : a chemico-physical investigation”. Bigiani L, Gasparotto A, Andreu T, Verbeeck J, Sada C, Modin E, Lebedev OI, Morante JR, Barreca D, Maccato C, Advanced sustainable systems , 2000177 (2020). http://doi.org/10.1002/ADSU.202000177
Abstract: Earth-abundant and eco-friendly manganese oxides are promising platforms for the oxygen evolution reaction (OER) in water electrolysis. Herein, a versatile and potentially scalable route to gold-decorated manganese oxide-based OER electrocatalysts is reported. In particular, MnxOy(MnO2, Mn2O3) host matrices are grown on conductive glasses by plasma assisted-chemical vapor deposition (PA-CVD), and subsequently functionalized with gold nanoparticles (guest) as OER activators by radio frequency (RF)-sputtering. The final selective obtainment of MnO2- or Mn2O3-based systems is then enabled by annealing under oxidizing or inert atmosphere, respectively. A detailed material characterization evidences the formation of high-purity Mn(x)O(y)dendritic nanostructures with an open morphology and an efficient guest dispersion into the host matrices. The tailoring of Mn(x)O(y)phase composition and host-guest interactions has a remarkable influence on OER activity yielding, for the best performing Au/Mn(2)O(3)system, a current density of approximate to 5 mA cm(-2)at 1.65 V versus the reversible hydrogen electrode (RHE) and an overpotential close to 300 mV at 1 mA cm(-2). Such results, comparing favorably with literature data on manganese oxide-based materials, highlight the importance of compositional control, as well as of surface and interface engineering, to develop low-cost and efficient anode nanocatalysts for water splitting applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.1
Times cited: 4
DOI: 10.1002/ADSU.202000177
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“Au@MOF-5 and Au/Mox@MOF-5 (M = Zn, Ti, x = 1, 2) : preparation and microstructural characterisation”. Müller M, Turner S, Lebedev OI, Wang Y, Van Tendeloo G, Fischer RA, European journal of inorganic chemistry , 1876 (2011). http://doi.org/10.1002/ejic.201001297
Abstract: The Zn-carboxylate-based porous coordination polymer MOF-5 [Zn4O(bdc)3] and the metal oxide loaded materials ZnO@MOF-5 and TiO2@MOF-5 were loaded in a second step with the precursor [ClAuCO] to yield intermediate materials denoted as [ClAuCO]@MOF-5, [ClAuCO]/ZnO@MOF-5 and [ClAuCO]/TiO2@MOF-5. These composites were decomposed to Au@MOF-5, Au/ZnO@MOF-5 and Au/TiO2@MOF-5 under hydrogen at 100 °C. The nanoparticle-loaded hybrid materials were characterised by powder X-ray diffraction (PXRD), IR spectroscopy, X-ray photoelectron spectroscopy (XPS) and N2 sorption measurements, which reveal an intact MOF-5 structure that maintains a high specific surface area. For Au@MOF-5, crystalline Au nanoparticles were distributed over the MOF matrix in a homogeneous fashion with a size of ca. 13 nm, evidenced by high resolution transmission electron microscopy. In the case of Au/ZnO@MOF-5, the Au and metal oxide particles of a few nm in size were coexistent in a given volume of the MOF-5 matrix and were not separated in different crystalline MOF particles. For the TiO2 loaded materials the oxide is preferentially located near the outer surface of the MOF particles, leading to an increase of larger exterior Au particles in comparison to very small interior Au particles as observed for the other materials. Au@MOF-5, Au/ZnO@MOF-5 and Au/TiO2@MOF-5 were tested in liquid-phase oxidation of alcohols. Preliminary results show a high activity for the Au loaded materials in this reaction. This observation is attributed to the microstructure of the composites with very small Au particles distributed homogeneously over the MOF matrix.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.444
Times cited: 75
DOI: 10.1002/ejic.201001297
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“Au@ZIFs: stabilization and encapsulation of cavity-size matching gold clusters inside functionalized Zeolite Imidazolate Frameworks, ZIFs”. Esken D, Turner S, Lebedev OI, Van Tendeloo G, Fischer RA, Chemistry of materials 22, 6393 (2010). http://doi.org/10.1021/cm102529c
Abstract: The selective formation and stabilization of very small, naked metal particles inside the cavities of metal organic frameworks (MOFs) and the simultaneous realization of an even distribution of the particles throughout the crystalline MOF host matrix over a wide range of metal loading are challenging goals. MOFs reveal high specific surface areas, tunable pore sizes, and organic linkers, which are able to interact with guests. The chemically very robust zeolite imidazolate frameworks (ZIFs) are a subclass of MOFs. We chose the microporous sodalite-like ZIF-8 (Zn(MelM)(2); IM = imidazolate) and ZIF-90 (Zn(ICA)(2); ICA = imidazolate-2-carboxyaldehyde) as host matrices to influence the dispersion of imbedded gold nanoparticles (Au NPs). The metal loading was achieved via gas phase infiltration of [Au(CO)Cl] followed by a thermal hydrogenation step to form the Au NPs. Low-dose high-resolution transmission electron microscopy ((HR)TEM) and electron tomography reveal a homogeneous distribution of Au NPs throughout the ZIF matrix. The functional groups of ZIF-90 direct the anchoring of intermediate Au species and stabilize drastically smaller and quite monodisperse Au NPs in contrast to the parent not functionalized ZIF-8. The particles can be very small, match the cavity size and approach defined molecular clusters of magic numbers, i.e., Au(55), independently from the level of loading. Post-synthetic oxidation of the aldehyde groups to yield alkyl esters by the adjacent, catalytically active metal NPs is presented as a new concept of encapsulating nanoparticles inside MOFs and allows multiple steps of metal loadings without decomposition of the MOF.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 194
DOI: 10.1021/cm102529c
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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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“Biaxially aligned yttria stabilized zirconia and titanium nitride layers deposited by unbalanced magnetron sputtering”. Mahieu S, Ghekiere P, de Winter G, de Gryse R, Depla D, Lebedev OI, Diffusion and defect data : solid state data : part B : solid state phenomena
T2 –, 2nd International Conference on Texture and Anisotropy of Polycrystals, JUL 07-09, 2004, Metz, FRANCE 105, 447 (2005)
Abstract: Control of the texture and the biaxial alignment of sputter deposited films has provoked a great deal of interest due to its technological importance. indeed, many physical properties of thin films are influenced by the biaxial alignment. In this context, extensive research has been established to understand the growth mechanism of biaxially aligned Yttria Stabilized Zirconia (YSZ) as a buffer layer for high temperature superconducting copper oxides. In this work, the growth mechanism in general and the mechanism responsible of the biaxial alignment in detail were investigated for thin films of YSZ and TiN deposited by unbalanced magnetron sputtering using non-aligned polycrystalline stainless steel substrates. The mechanism responsible for the preferential out-of-plane alignment has been investigated by performing depositions on a non-tilted substrate. However, to study the in-plane alignment a tilted substrate was used. The microstructure of the deposited layers was characterised by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The crystallographic alignment has been investigated by X-ray diffraction (XRD) (angular scans and pole figures) and by Selective Area Diffraction (SAD). It was observed that the deposited layers show a zone T or zone II structure and the layers with a zone T structure consist of faceted grains. There seems to be a correlation between the crystal habit of these faceted grains and the measured biaxial alignment. A model for the preferential out-of-plane orientation, the in-plane alignment and the correlation between the microstructure and the biaxial alignment is proposed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
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“Catalytic characterization of pure SnO2 and GeO2 in methanol steam reforming”. Zhao Q, Lorenz H, Turner S, Lebedev OI, Van Tendeloo G, Rameshan C, Klötzer B, Konzett J, Penner S, Applied catalysis : A : general 375, 188 (2010). http://doi.org/10.1016/j.apcata.2009.12.027
Abstract: Structural changes of a variety of different SnO, SnO2 and GeO2 catalysts upon reduction in hydrogen were correlated with associated catalytic changes in methanol steam reforming. Studied systems include SnO, SnO2 and GeO2 thin film model catalysts prepared by vapour phase deposition and growth on polycrystalline NaCl surfaces and, for comparison, the corresponding pure oxide powder catalysts. Reduction of both the SnO2 thin film and powder at around 673 K in 1 bar hydrogen leads to a substantial reduction of the bulk structure and yields a mixture of SnO2 and metallic β-Sn. On the powder catalyst this transformation is fully reversible upon oxidation in 1 bar O2 at 673 K. Strongly reduced thin films, however, can only be re-transformed to SnO2 if the reduction temperature did not exceed 573 K. For GeO2, the situation is more complex due to its polymorphism. Whereas the tetragonal phase is structurally stable during reduction, oxidation or catalytic reaction, a small part of the hexagonal phase is always transformed into the tetragonal at 673 K independent of the gas phase used. SnO2 is highly active and CO2 selective in methanol steam reforming, but the initial high activity drops considerably upon reduction between 373 and 573 K and almost complete catalyst deactivation is observed after reduction at 673 K, which is associated with the parallel formation of β-Sn. In close correlation to the structural results, the catalytic activity and selectivity can be restored upon an oxidative catalyst regeneration at 673 K. Tetragonal GeO2 exhibits only a small activity and no pronounced selectivity to either CO or CO2, at least after reduction. In its fully oxidized state release of surface/lattice oxygen results in a non-catalytic formation of CO2 by oxidation of CO originating from catalytic dehydrogenation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.339
Times cited: 20
DOI: 10.1016/j.apcata.2009.12.027
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“Characterisation of multilayer ramp-type REBa2Cu3O7-\delta structures by scanning probe microscopy and high-resolution electron microscopy”. Blank DHA, Rijnders AJHM, Verhoeven MAJ, Bergs RMH, Rogalla H, Verbist K, Lebedev O, Van Tendeloo G, Journal of alloys and compounds
T2 –, Symposium on High Temperature Superconductor Thin Films, Growth, Mechanisms, Interfaces, Multilayers, at the 1996 Spring Meeting of the European-Materials-Society, June 04-07, 1996, Strasbourg, France 251, 206 (1997). http://doi.org/10.1016/S0925-8388(96)02799-5
Abstract: We studied the morphology of ramps in REBa2CU3O7 (REBCO) epitaxial films on SrTiO3 substrates, fabricated by RF magnetron sputter deposition and pulsed laser deposition (PLD), by scanning probe microscopy (SPM) and high resolution electron microscopy (HREM). The ramps were fabricated by Ar ion beam etching using masks of standard photoresist and TIN. AFM-studies on ramps in sputter deposited films show a strong dependence, i.e. formation of facets and ridges, on the angle of incidence of the ion beam with respect to the substrate surface as well as the rotation angle with respect to the crystal axes of the substrate. Ramps in pulsed laser deposited films did not show this dependence, Furthermore, we studied the effect of an anneal step prior to the deposition of barrier layers (i.e. PrBa2CU3O7, SrTiO3, CeO2) on the ramp. First results show a recrystallization of the ramp surface, resulting in terraces and a non-homogeneous growth of the barrier material on top of it. The thickness variations, for thin layers of barrier material, con even become much larger than expected from the amount of deposited material and are dependent on the deposition and anneal conditions. HREM studies show a well defined interface between barrier layer and electrodes. The angle of the ramp depends on the etch rate of the mask and REBCO, and on the angle of incidence of the ion beam. TiN has a much lower etch rate compared to photoresist, resulting in an angle of the ramp comparable to the angle of incidence, resulting in a low etching rate on the ramp. These results will lead to improved electrical characteristics of ramp-type junctions.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
DOI: 10.1016/S0925-8388(96)02799-5
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“Characterization of oxide precipitates in heavily B-doped silicon by infrared spectroscopy”. de Gryse O, Clauws P, Vanhellemont J, Lebedev OI, van Landuyt J, Simoen E, Claeys C, Journal of the electrochemical society 151, G598 (2004). http://doi.org/10.1149/1.1776592
Abstract: Infrared absorption spectra of oxygen precipitates in boron-doped silicon with a boron concentration between 10(17) and 10(19) cm(-3) are analyzed, applying the spectral function representation of composite materials. The aspect ratio of the platelet precipitates is determined by transmission electron microscopy measurements. The analysis shows that in samples with moderate doping levels (<10(18) B cm(-3)) SiOγ precipitates are formed with the same composition as in the lightly doped case. In the heavily boron-doped (>10(18) cm(-3)) samples, however, the measured spectra of the precipitates are consistent with a mixture of SiO2 and B2O3, with a volume fraction of B2O3 as high as 0.41 in the most heavily doped case. (C) 2004 The Electrochemical Society.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.259
Times cited: 13
DOI: 10.1149/1.1776592
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“Chemical and structural characterization of oxide precipitates in heavily boron doped silicon by infrared spectroscopy and transmission electron microscopy”. De Gryse O, Clauws P, Vanhellemont J, Lebedev O, van Landuyt J, Simoen E, Claeys C, , 183 (2002)
Abstract: Infrared absorption spectra of oxygen precipitates in boron doped silicon with a boron concentration between 10(17) and 10(19) cm(-3) are analyzed, applying the spectral function theory of the composite precipitates. The aspect ratio of the platelet precipitates has been determined by transmission electron microscopy measurements. Our analysis shows that in samples with moderate doping levels (<10(18) B cm(-3)) SiOgamma precipitates are formed with stoichiometry as in the lightly doped case. In the heavily (>10(18) cm(-3)) boron doped samples, however, the measured spectra of the precipitates are consistent with a mixture of SiO2 and B2O3. with a volume fraction of B2O3 as high as 0.41 in the most heavily doped case.
Keywords: P1 Proceeding; Electron microscopy for materials research (EMAT)
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“Chemical and structural characterization of oxygen precipitates in silicon by infrared spectroscopy and TEM”. de Gryse O, Clauws P, Lebedev O, van Landuyt J, Vanhellemont J, Claeys C, Simoen E, Physica: B : condensed matter
T2 –, 21st International Conference on Defects in Semiconductors, JUL 16-20, 2001, GIESSEN, GERMANY 308, 294 (2001). http://doi.org/10.1016/S0921-4526(01)00801-8
Abstract: Infrared absorption spectra of polyhedral and platelet oxygen precipitates are analyzed using a modified Day-Thorpe approach (J. Phys.: Condens. Matter 11 (1999) 2551). The aspect ratio has been determined by TEM measurements. The reduced spectral function and the stoichiometry are extracted from the absorption spectra and the concentration of precipitated interstitial oxygen. One set of spectra reveal a Frohlich frequency around 1100 cm(-1) and another around 1110-1120 cm(-1). It is shown that the shift in the Frohlich frequency is not due to a different stoichiometry, but due to the detailed structure in the reduced spectral function. The oxygen precipitates consist of SiO. with gammaapproximate to1.1-1.2+/-0.1. (C) 2001 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.386
Times cited: 3
DOI: 10.1016/S0921-4526(01)00801-8
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“Classification and control of the origin of photoluminescence from Si nanocrystals”. Godefroo S, Hayne M, Jivanescu M, Stesmans A, Zacharias M, Lebedev OI, Van Tendeloo G, Moshchalkov VV, Nature nanotechnology 3, 174 (2008). http://doi.org/10.1038/nnano.2008.7
Abstract: Silicon dominates the electronics industry, but its poor optical properties mean that III-V compound semiconductors are preferred for photonics applications. Photoluminescence at visible wavelengths was observed from porous Si at room temperature in 1990, but the origin of these photons (do they arise from highly localized defect states or quantum confinement effects?) has been the subject of intense debate ever since. Attention has subsequently shifted from porous Si to Si nanocrystals, but the same fundamental question about the origin of the photoluminescence has remained. Here we show, based on measurements in high magnetic fields, that defects are the dominant source of light from Si nanocrystals. Moreover, we show that it is possible to control the origin of the photoluminescence in a single sample: passivation with hydrogen removes the defects, resulting in photoluminescence from quantum-confined states, but subsequent ultraviolet illumination reintroduces the defects, making them the origin of the light again.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 38.986
Times cited: 426
DOI: 10.1038/nnano.2008.7
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“Commensurate structural modulation in the charge- and orbitally ordered phase of the quadruple perovskite (NaMn3)Mn4O12”. Prodi A, Daoud-Aladine A, Gozzo F, Schmitt B, Lebedev O, Van Tendeloo G, Gilioli E, Bolzoni F, Aruga-Katori H, Takagi H, Marezio M, Gauzzi A;, Physical review : B : condensed matter and materials physics 90, 180101 (2014). http://doi.org/10.1103/PhysRevB.90.180101
Abstract: By means of synchrotron x-ray and electron diffraction, we studied the structural changes at the charge order transition T-CO = 176 K in the mixed-valence quadruple perovskite (NaMn3)Mn4O12. Below T-CO we find satellite peaks indicating a commensurate structural modulation with the same propagation vector q = ( 1/2,0,-1/2) of the CE magnetic structure that orders at low temperatures, similarly to the case of simple perovskites such as La0.5Ca0.5MnO3. In the present case, the modulated structure, together with the observation of a large entropy change at T-CO, gives evidence of a rare case of full Mn3+/Mn4+ charge and orbital order, consistent with the Goodenough-Kanamori model.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 11
DOI: 10.1103/PhysRevB.90.180101
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“Controlled formation of amine-templated mesostructured zirconia with remarkably high thermal stability”. Cassiers K, Linssen T, Aerts K, Cool P, Lebedev O, Van Tendeloo G, van Grieken R, Vansant EF, Journal of materials chemistry 13, 3033 (2003). http://doi.org/10.1039/b310200a
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 26
DOI: 10.1039/b310200a
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“Controlled vapor-phase synthesis of cobalt oxide nanomaterials with tuned composition and spatial organization”. Barreca D, Gasparotto A, Lebedev OI, Maccato C, Pozza A, Tondello E, Turner S, Van Tendeloo G, CrystEngComm 12, 2185 (2010). http://doi.org/10.1039/b926368n
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.474
Times cited: 85
DOI: 10.1039/b926368n
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“Correlation of microstructure and magnetotransport properties of epitaxially grown La-Ca-Mn-O3 thin films”. Habermeier HU, Razavi F, Lebedev O, Gross GM, Praus R, Zhang PX, Physica status solidi: B: basic research
T2 –, International Conference on Solid State Spectroscopy –, (ICSSS), SEP 05-07, 1999, SCHWABISCH-GMUND, GERMANY 215, 679 (1999). http://doi.org/10.1002/(SICI)1521-3951(199909)215:1<679::AID-PSSB679>3.0.CO;2-H
Abstract: We have investigated epitaxially grown single-crystalline Ca-doped LaMnO3 thin films using the pulsed laser deposition technique in a case study aimed to explore the possibilities buried in epitaxial stress tailoring in order to control the transport properties of CMR materials beyond the limits set by equilibrium thermodynamics. Depending on the film thickness there is an abrupt transition from pseudomorphic to epitaxial granular growth observable which is related to the epitaxial strain of the films. This is associated with microscopic stress relaxation and leads to well controllable modifications of the atomic arrangements of the Mn-O sublattice in the films. Due to the interrelation of double exchange, spin-, charge- and orbital ordering and the Jahn-Teller effect mediated coupling of the electronic system to the crystal lattice, the magnetotransport properties of the firms can be modified in a controllable way.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.674
Times cited: 3
DOI: 10.1002/(SICI)1521-3951(199909)215:1<679::AID-PSSB679>3.0.CO;2-H
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“Corrigendum: Structural phase transition at the percolation threshold in epitaxial (La0.7Ca0.3MnO3)1-x:(MgO)x nanocomposite films”. Moshnyaga V, Damaschke B, Shapoval O, Belenchuk A, Faupel J, Lebedev OI, Verbeeck J, Van Tendeloo G, Mücksch M, Tsurkan V, Tidecks R, Samwer K, Nature materials 4, 104 (2005)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 39.737
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