“Influence of strain, specimen orientation and background estimation on composition evaluation of InAs/GaAs by TEM”. Rossi EHM, Van Tendeloo G, Rosenauer A, Philosophical magazine 87, 4461 (2007). http://doi.org/10.1080/14786430701551905
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.505
Times cited: 1
DOI: 10.1080/14786430701551905
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“Segregation in InxGa1-xAs/GaAs Stranski-Krastanow layers grown by metal-organic chemical vapour deposition”. Piscopiello E, Rosenauer A, Passaseo A, Montoya Rossi EH, Van Tendeloo G, Philosophical magazine 85, 3857 (2005). http://doi.org/10.1080/147830500269402
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.505
Times cited: 11
DOI: 10.1080/147830500269402
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“Structure and microstructure of epitaxial SrnFenO3n-1 films”. Lebedev OI, Verbeeck J, Van Tendeloo G, Hayashi N, Terashima T, Takano M, Philosophical magazine 84, 3825 (2004). http://doi.org/10.1080/14786430412331313187
Abstract: Thin films of SrFeO3-x (0 less than or equal to x less than or equal to 0.5) (SFO) grown on a (LaAlO3)(0.3) (SrAl0.5Ta0.5O3)(0.7) (LSAT) substrate by Pulsed laser deposition have been structurally investigated by electron diffraction and high resolution transmission electron microscopy for different post-deposition oxygen treatments. During the deposition and post-growth oxidation, the oxygen-reduced SFO films accept extra oxygen along the tetrahedral layers to minimize the elastic strain energy. The oxidation process stops at a concentration SFO2.875 and/or SFO2.75 because a zero misfit with the LSAT substrate is reached. A possible growth mechanism and phase transition mechanism are suggested. The non-oxidized films exhibit twin boundaries having a local perovskite-type structure with a nominal composition close to SFO3.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.505
Times cited: 4
DOI: 10.1080/14786430412331313187
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“TEM investigation of the formation mechanism of deformation twins in Fe-Mn-Si-Al TWIP steels”. Idrissi H, Renard K, Schryvers D, Jacques PJ, Philosophical magazine 93, 4378 (2013). http://doi.org/10.1080/14786435.2013.832837
Abstract: The microstructure of a Fe-Mn-Si-Al twinning-induced plasticity (TWIP) steel exhibiting remarkable work hardening rate under uniaxial tensile deformation was investigated using transmission electron microscopy to uncover the mechanism(s) controlling the nucleation and growth of the mechanically induced twins. The results show that the stair-rod cross-slip deviation mechanism is necessary for the formation of the twins, while large extrinsic stacking faults homogenously distributed within the grains could act as preferential sources for the activation of the deviation process. The influence of such features on the thickness and strength of the twins and the resulting mechanical behaviour is discussed and compared to similar works recently performed on Fe-Mn-C TWIP steels.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.505
Times cited: 15
DOI: 10.1080/14786435.2013.832837
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“Transmission electron microscopy study of phase compatibility in low hysteresis shape memory alloys”. Delville R, Kasinathan S, Zhang Z, van Humbeeck J, James RD, Schryvers D, Philosophical magazine 90, 177 (2010). http://doi.org/10.1080/14786430903074755
Abstract: Recent findings have linked low hysteresis in shape memory alloys with phase compatibility between austenite and martensite. To investigate the evolution of microstructure as phase compatibility increases and hysteresis is reduced, transmission electron microscopy was used to study the alloy system Ti50Ni50xPdx, where the composition is systemically tuned to approach perfect compatibility. Changes in morphology, twinning density and twinning modes are reported, along with special microstructures occurring when compatibility is achieved. In addition, the interface between austenite and a single variant of martensite was studied by high-resolution and conventional electron microscopy. The low energy configuration of the interface detailed in this article suggests that it plays an important role in the lowering of hysteresis compared to classical habit plane interfaces.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.505
Times cited: 70
DOI: 10.1080/14786430903074755
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“Parametrization and Molecular Dynamics Simulations of Nitrogen Oxyanions and Oxyacids for Applications in Atmospheric and Biomolecular Sciences”. Cordeiro RM, Yusupov M, Razzokov J, Bogaerts A, Journal Of Physical Chemistry B 124, 1082 (2020). http://doi.org/10.1021/acs.jpcb.9b08172
Abstract: Nitrogen oxyanions and oxyacids are important agents in atmospheric chemistry and medical biology. Although their chemical behavior in solution is relatively well understood, they may behave very differently at the water/air interface of atmospheric aerosols or at the membrane/water interface of cells. Here, we developed a fully classical model for molecular dynamics simulations of NO3−, NO2−, HNO3, and HNO2 in the framework of the GROMOS 53A6 and 54A7 force field versions. The model successfully accounted for the poorly structured solvation shell and ion pairing tendency of NO3−. Accurate pure-liquid properties and hydration free energies were obtained for the oxyacids. Simulations at the water/air interface showed a local enrichment of HNO3 and depletion of NO3−. The effect was discussed in light of earlier spectroscopic data and ab initio calculations, suggesting that HNO3 behaves as a weaker acid at the surface of water. Our model will hopefully allow for efficient and accurate simulations of nitrogen oxyanions and oxyacids in solution and at microheterogeneous interface environments.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.3
DOI: 10.1021/acs.jpcb.9b08172
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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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“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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“Approaches to calculation of exciton interaction energies for a molecular dimer”. Howard IA, Zutterman F, Deroover G, Lamoen D, van Alsenoy C, Journal Of Physical Chemistry B 108, 19155 (2004). http://doi.org/10.1021/jp040417h
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 3.177
Times cited: 35
DOI: 10.1021/jp040417h
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“Hydrothermal synthesis and characterization of nanorods of various titanates and titanium dioxide”. Kolen'ko YV, Kovnir KA, Gavrilov AI, Garshev AV, Frantti J, Lebedev OI, Churagulov BR, Van Tendeloo G, Yoshimura M, The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical 110, 4030 (2006). http://doi.org/10.1021/jp055687u
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.177
Times cited: 234
DOI: 10.1021/jp055687u
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“The influence of the alcohol concentration on the structural ordering of mesoporous silica: cosurfactant versus cosolvent”. Liu S, Cool P, Collart O, van der Voort P, Vansant EF, Lebedev OI, Van Tendeloo G, Jiang M, The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical 107, 10405 (2003). http://doi.org/10.1021/jp034410w
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.177
Times cited: 134
DOI: 10.1021/jp034410w
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“Investigation of the morphology of the mesoporous SBA-16 and SBA-15 materials”. Stevens WJJ, Lebeau K, Mertens M, Van Tendeloo G, Cool P, Vansant EF, The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical 110, 9183 (2006). http://doi.org/10.1021/jp0548725
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Electron microscopy for materials research (EMAT)
Impact Factor: 3.177
Times cited: 109
DOI: 10.1021/jp0548725
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“Leached natural saponite as the silicate source in the synthesis of aluminosilicate hexagonal mesoporous materials”. Linssen T, Cool P, Baroudi M, Cassiers K, Vansant EF, Lebedev O, van Landuyt J, The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical 106, 4470 (2002). http://doi.org/10.1021/jp015578p
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.177
Times cited: 23
DOI: 10.1021/jp015578p
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“Structural, textural, and electronic properties of a nanosized mesoporous ZnxTi1-xO2-x solid solution prepared by a supercritical drying route”. Kolen'ko YV, Kovnir KA, Gavrilov AI, Garshev AV, Meskin PE, Churagulov BR, Bouchard M, Colbeau-Justin C, Lebedev OI, Van Tendeloo G, Yoshimura M, Journal of physical chemistry B 109, 20303 (2005). http://doi.org/10.1021/jp0535341
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.177
Times cited: 34
DOI: 10.1021/jp0535341
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“A Universal Deposition Protocol for Planar Heterojunction Solar Cells with High Efficiency Based on Hybrid Lead Halide Perovskite Families”. Conings B, Babayigit A, Klug M T, Bai S, Gauquelin N, Sakai N, Wang J T-W, Verbeeck J, Boyen H-G, Advanced materials 28, 10701 (2016). http://doi.org/10.1002/adma.201603747
Abstract: A robust and expedient gas quenching method is developed for the solution deposition of hybrid perovskite thin films. The method offers a reliable standard practice for the fabrication of a non-exhaustive variety of perovskites exhibiting excellent film morphology and commensurate high performance in both regular and inverted structured solar cell architectures.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 19.791
Times cited: 95
DOI: 10.1002/adma.201603747
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“Element Specific Monolayer Depth Profiling”. Macke S, Radi A, Hamann-Borrero JE, Verna A, Bluschke M, Brück S, Goering E, Sutarto R, He F, Cristiani G, Wu M, Benckiser E, Habermeier H-U, Logvenov G, Gauquelin N, Botton GA, Kajdos AP, Stemmer S, Sawatzky GA, Haverkort MW, Keimer B, Hinkov V, Advanced Materials 26, 6554 (2014). http://doi.org/10.1002/adma.201402028
Abstract: The electronic phase behavior and functionality of interfaces and surfaces in complex materials are strongly correlated to chemical composition profiles, stoichiometry and intermixing. Here a novel analysis scheme for resonant X-ray reflectivity maps is introduced to determine such profiles, which is element specific and non-destructive, and which exhibits atomic-layer resolution and a probing depth of hundreds of nanometers.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT)
Impact Factor: 19.791
Times cited: 34
DOI: 10.1002/adma.201402028
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“Artifact Reduction Based on Sinogram Interpolation for the 3D Reconstruction of Nanoparticles Using Electron Tomography”. Sentosun K, Lobato I, Bladt E, Zhang Y, Palenstijn WJ, Batenburg KJ, Van Dyck D, Bals S, Particle and particle systems characterization 34, 1700287 (2017). http://doi.org/10.1002/ppsc.201700287
Abstract: Electron tomography is a well-known technique providing a 3D characterization of the morphology and chemical composition of nanoparticles. However, several reasons hamper the acquisition of tilt series with a large number of projection images, which deteriorate the quality of the 3D reconstruction. Here, an inpainting method that is based on sinogram interpolation is proposed, which enables one to reduce artifacts in the reconstruction related to a limited tilt series of projection images. The advantages of the approach will be demonstrated for the 3D characterization of nanoparticles using phantoms and several case studies.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Vision lab
Times cited: 2
DOI: 10.1002/ppsc.201700287
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“Groundwater remediation and the cost effectiveness of phytoremediation”. Compernolle T, Van Passel S, Weyens N, Vangronsveld J, Lebbe L, Thewys T, International Journal Of Phytoremediation 14, 861 (2012). http://doi.org/10.1080/15226514.2011.628879
Abstract: In 1999, phytoremediation was applied at the site of a Belgian car factory to contain two BTEX plumes. This case study evaluates the cost effectiveness of phytoremediation compared to other remediation options, applying a tailored approach for economic evaluation. Generally, when phytoremediation is addressed as being cost effective, the cost effectiveness is only determined on an average basis. This study however, demonstrates that an incremental analysis may provide a more nuanced conclusion. When the cost effectiveness is calculated on an average basis, in this particular case, the no containment strategy (natural attenuation) has the lowest cost per unit mass removed and hence, should be preferred. However, when the cost effectiveness is determined incrementally, no containment should only be preferred if the value of removing an extra gram of contaminant mass is lower than 320. Otherwise, a permeable reactive barrier should be adopted. A similar analysis is provided for the effect determined on the basis of remediation time. Phytoremediation is preferred compared to no containment if reaching the objective one year earlier is worth 7 000.
Keywords: A1 Journal article; Economics; Engineering Management (ENM)
Impact Factor: 1.77
Times cited: 12
DOI: 10.1080/15226514.2011.628879
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“Capturing the real-time hydrolytic degradation of a library of biomedical polymers by combining traditional assessment and electrochemical sensors”. Fuoco T, Cuartero M, Parrilla M, García-Guzmán JJ, Crespo GA, Finne-Wistrand A, Biomacromolecules 22, 949 (2021). http://doi.org/10.1021/ACS.BIOMAC.0C01621
Abstract: We have developed an innovative methodology to overcome the lack of techniques for real-time assessment of degradable biomedical polymers at physiological conditions. The methodology was established by combining polymer characterization techniques with electrochemical sensors. The in vitro hydrolytic degradation of a series of aliphatic polyesters was evaluated by following the molar mass decrease and the mass loss at different incubation times while tracing pH and l-lactate released into the incubation media with customized miniaturized electrochemical sensors. The combination of different analytical approaches provided new insights into the mechanistic and kinetics aspects of the degradation of these biomedical materials. Although molar mass had to reach threshold values for soluble oligomers to be formed and specimens’ resorption to occur, the pH variation and l-lactate concentration were direct evidence of the resorption of the polymers and indicative of the extent of chain scission. Linear models were found for pH and released l-lactate as a function of mass loss for the l-lactide-based copolymers. The methodology should enable the sequential screening of degradable polymers at physiological conditions and has potential to be used for preclinical material’s evaluation aiming at reducing animal tests.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 5.246
DOI: 10.1021/ACS.BIOMAC.0C01621
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“Polydopamine-gelatin as universal cell-interactive coating for methacrylate-based medical device packaging materials : when surface chemistry overrules substrate bulk properties”. Van de Walle E, Van Nieuwenhove I, Vanderleyden E, Declercq H, Gellynck K, Schaubroeck D, Ottevaere H, Thienpont H, De Vos WH, Cornelissen M, Van Vlierberghe S, Dubruel P, Biomacromolecules 17, 56 (2016). http://doi.org/10.1021/ACS.BIOMAC.5B01094
Abstract: Despite its widespread application in the fields of ophthalmology, orthopedics and dentistry and the stringent need for polymer packagings that induce in vivo tissue integration, the full potential of poly(methyl methacrylate) (PMMA) and its derivatives as medical device packaging material has not been explored yet. We therefore elaborated on the development of a universal coating for methacrylate-based materials which ideally should reveal cell-interactivity irrespective of the polymer substrate bulk properties. Within this perspective, the present work reports on the UV-induced synthesis of PMMA and its more flexible poly(ethyleneglycol) (PEG)-based derivative (PMMAPEG) and its subsequent surface decoration using polydopamine (PDA) as well as PDA combined with gelatin B (Gel B). Successful application of both layers was confirmed by multiple surface characterization techniques. The cell interactivity of the materials was studied by performing live-dead assays and immunostainings of the cytoskeletal components of fibroblasts. It can be concluded that only the combination of PDA and Gel B yields materials posessing similar cell interactivities, irrespective of the physicochemical properties of the underlying substrate. The proposed coating outperforms both the PDA functionalized and the pristine polymer surfaces. A universal cell-interactive coating for methacrylate-based medical device packaging materials has thus been realized.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/ACS.BIOMAC.5B01094
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“Elucidation of the Growth Mechanism of Sputtered 2D Hexagonal Boron Nitride Nanowalls”. Hoang D-Q, Pobedinskas P, Nicley SS, Turner S, Janssens SD, Van Bael MK, D'Haen J, Haenen K, Crystal growth &, design 16, 3699 (2016). http://doi.org/10.1021/ACS.CGD.6B00191
Abstract: Hexagonal boron nitride nanowall thin films were deposited on Si(100) substrates using a Ar(51%)/N-2(44%)/H-2(5%) gas mixture by unbalanced radio frequency sputtering. The effects of various target-to-substrate distances, substrate temperatures, and substrate tilting angles were investigated. When the substrate is close to the target, hydrogen etching plays a significant role in the film growth, while the effect is negligible for films deposited at a farther distance. The relative quantity of defects was measured by a non-destructive infrared spectroscopy technique that characterized the hydrogen incorporation at dangling nitrogen bonds at defect sites in the deposited films. Despite the films deposited at different substrate tilting angles, the nanowalls of those films were found to consistently grow vertical to the substrate surface, independent of the tilting angle. This implies that chemical processes, rather than physical ones, govern the growth of the nanowalls. The results also reveal that the degree of nanowall crystallization is tunable by varying the growth parameters. Finally, evidence of hydrogen desorption during vacuum annealing is given based on measurements of infrared stretching (E-1u) and bending (A(2u)) modes of the optical phonons, and the H-N vibration mode.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.055
Times cited: 8
DOI: 10.1021/ACS.CGD.6B00191
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“On the Origin of Diamond Plates Deposited at Low Temperature”. Drijkoningen S, Pobedinskas P, Korneychuk S, Momot A, Balasubramaniam Y, Van Bael MK, Turner S, Verbeeck J, Nesladekt M, Haenen K, Crystal growth &, design 17, 4306 (2017). http://doi.org/10.1021/ACS.CGD.7B00623
Abstract: The crucial requirement for diamond growth at low temperatures, enabling a wide range of new applications, is a high plasma density at a low gas pressure, which leads to a low thermal load onto sensitive substrate materials. While these conditions are not within reach for resonance cavity plasma systems, linear antenna microwave delivery systems allow the deposition of high quality diamond films at temperatures around 400 degrees C and at pressures below 1 mbar. In this work the codeposition of high quality plates and octahedral diamond grains in nanocrystalline films is reported. In contrast to previous reports claiming the need for high temperatures (T >= 850 degrees C), low temperatures (320 degrees C <= T <= 410 degrees C) were sufficient to deposit diamond plate structures. Cross-sectional high resolution transmission electron microscopy studies show that these plates are faulty cubic diamond terminated by large {111} surface facets with very little sp(2) bonded carbon in the grain boundaries. Raman and electron energy loss spectroscopy studies confirm a high diamond quality, above 93% sp(3) carbon content. Three potential mechanisms, that can account for the initial development of the observed plates rich with stacking faults, and are based on the presence of impurities, are proposed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.055
Times cited: 23
DOI: 10.1021/ACS.CGD.7B00623
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“Controlled Growth of Supported ZnO Inverted Nanopyramids with Downward Pointing Tips”. Barreca D, Carraro G, Maccato C, Altantzis T, Kaunisto K, Gasparotto A, Crystal growth &, design , acs.cgd.8b00198 (2018). http://doi.org/10.1021/acs.cgd.8b00198
Abstract: High purity porous ZnO nanopyramids with controllable properties are grown on their tips on
Si(100) substrates by means of a catalyst-free vapor phase deposition route in a wet oxygen
reaction environment. The system degree of preferential [001] orientation, as well as
nanopyramid size, geometrical shape and density distribution, can be finely tuned by varying the
growth temperature between 300 and 400°C, whereas higher temperatures lead to more compact
systems with a three-dimensional (3D) morphology. A growth mechanism of the obtained ZnO
nanostructures based on a self-catalytic vapor-solid (VS) mode is proposed, in order to explain
the evolution of nanostructure morphologies as a function of the adopted process conditions. The
results obtained by a thorough chemico-physical characterization enable to get an improved
control over the properties of ZnO nanopyramids grown by this technique. Taken together, they
are of noticeable importance not only for fundamental research on ZnO nanomaterials with
controlled nano-organization, but also to tailor ZnO functionalities in view of various potential
applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.055
Times cited: 6
DOI: 10.1021/acs.cgd.8b00198
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“CVD of copper oxides from a \beta-diketonate diamine precursor: tailoring the nano-organization”. Barreca D, Gasparotto A, Maccato C, Tondello E, Lebedev OI, Van Tendeloo G, Crystal growth &, design 9, 2470 (2009). http://doi.org/10.1021/cg801378x
Abstract: A copper(II) hexafluoroacetylacetonate (1,1,1,5,5,5-hexafluoro-2,4-pentanedionate, hfa) adduct with N,N,N¡ä,N¡ä-tetramethylethylenediamine (TMEDA) [Cu(hfa)2¡¤TMEDA] is used for the first time as precursor for the chemical vapor deposition (CVD) of copper oxide nanosystems. The syntheses are carried out under both O2 and O2+H2O reaction atmospheres on Si(100) substrates, at temperatures ranging between 250 and 550 ¡ãC. Subsequently, the interrelations between the preparative conditions and the system composition, nanostructure, and morphology are elucidated by means of complementary analytical techniques [Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron and X-ray excited auger electron spectroscopies (XPS and XE-AES), glancing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM)]. The obtained data revealed a gradual transformation from Cu2O, to Cu2O + CuO, to CuO nanosystems upon increasing the deposition temperature from 250 to 550 ¡ãC under both growth atmospheres. Such a phenomenon was accompanied by a progressive morphological evolution from continuous films to 1D hyperbranched nanostructures. Water vapor introduction in the deposition environment enabled to lower the deposition temperature and resulted in a higher aggregate interconnection, attributed to a higher density of nucleation centers.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.055
Times cited: 60
DOI: 10.1021/cg801378x
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“Differences between ultrananocrystalline and nanocrystalline diamond growth: theoretical investigation of CxHy species at diamond step edges”. Eckert M, Neyts E, Bogaerts A, Crystal growth &, design 10, 4123 (2010). http://doi.org/10.1021/cg100804v
Abstract: The behavior of hydrocarbon species at step edges of diamond terraces is investigated by means of combined molecular dynamics−Metropolis Monte Carlo simulations. The results show that the formation of ballas-like diamond films (like UNCD) and well-faceted diamond films (like NCD) can be related to the gas phase concentrations of CxHy in a new manner: Species that have high concentrations above the growing UNCD films suppress the extension of step edges through defect formation. The species that are present above the growing NCD film, however, enhance the extension of diamond terraces, which is believed to result in well-faceted diamond films. Furthermore, it is shown that, during UNCD growth, CxHy species with x ≥ 2 play an important role, in contrast to the currently adopted CVD diamond growth mechanism. Finally, the probabilities for the extension of the diamond (100) terrace are much higher than those for the diamond (111) terrace, which is in full agreement with the experimental observation that diamond (100) facets are more favored than diamond (111) facets during CVD diamond growth.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.055
Times cited: 11
DOI: 10.1021/cg100804v
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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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“Highly oriented ZnO nanorod arrays by a novel plasma chemical vapor deposition process”. Bekermann D, Gasparotto A, Barreca D, Bovo L, Devi A, Fischer RA, Lebedev OI, Maccato C, Tondello E, Van Tendeloo G, Crystal growth &, design 10, 2011 (2010). http://doi.org/10.1021/cg1002012
Abstract: Strongly c-axis oriented ZnO nanorod arrays were grown on Si(100) by plasma enhanced-chemical vapor deposition (PE-CVD) starting from two volatile bis(ketoiminato) zinc(II) compounds Zn[(R′)NC(CH3)═C(H)C(CH3)═O]2, with R′ = -(CH2)xOCH3 (x = 2, 3). A systematic investigation of process parameters enabled us to obtain the selective formation of ZnO nanorods with tailored features, and provided an important insight into their growth mechanism. The morphology, structure, and composition of the synthesized ZnO nanosystems were thoroughly analyzed by field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDXS), glancing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Photoluminescence (PL) measurements were carried out to gain information on the optical properties. Specifically, one-dimensional (1D) ZnO architectures could be grown on Si(100) substrates at temperatures as low as 200−300 °C and radio frequency (RF)-power values of 20 W, provided that a sufficiently high mass supply to the growth surface was maintained. To the best of our knowledge, the present work reports the mildest preparation conditions ever appeared in the literature for the PE-CVD of ZnO nanorods, a key result in view of potential large-scale technological applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.055
Times cited: 75
DOI: 10.1021/cg1002012
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“Insight into the growth of multiple branched MnOOH nanorods”. Li Y, Tan H, Lebedev O, Verbeeck J, Biermans E, Van Tendeloo G, Su B-L, Crystal growth &, design 10, 2969 (2010). http://doi.org/10.1021/cg100009k
Abstract: Multiple branched manganese oxide hydroxide (MnOOH) nanorods prepared by a hydrothermal process were extensively studied by transmission electron microscopy (TEM). A model of the branch formation is proposed together with a study of the interface structure. The sword-like tip plays a crucial role for the nanorods to form different shapes. Importantly, the branching occurs at an angle of around either 57 degrees or 123 degrees. Specifically, a (111) twin plane can only be formed at the interface with a 123 degrees angle. The interfaces formed with a 57 degrees angle usually contain edge dislocations. Electron energy loss spectroscopy (EELS) demonstrates that the whole crystal has a uniform chemical composition. Interestingly, an epitaxial growth of Mn3O4 at the radial surface was also observed under electron beam irradiation; this is because of the rough purification of the products. The proposed mechanism is expected to shed light on the branched/dendrite nanostructure growth and to provide opportunities for further novel nanomaterial structure growth and design.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.055
Times cited: 41
DOI: 10.1021/cg100009k
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“Insights into the growth of (ultra)nanocrystalline diamond by combined molecular dynamics and Monte Carlo simulations”. Eckert M, Neyts E, Bogaerts A, Crystal growth &, design 10, 3005 (2010). http://doi.org/10.1021/cg100063c
Abstract: In this paper, we present the results of combined molecular dynamics−Metropolis Monte Carlo (MD-MMC) simulations of hydrocarbon species at flat diamond (100)2 × 1 and (111)1 × 1 surfaces. The investigated species are considered to be the most important growth species for (ultra)nanocrystalline diamond ((U)NCD) growth. When applying the MMC algorithm to stuck species at monoradical sites, bonding changes are only seen for CH2. The sequence of the bond breaking and formation as put forward by the MMC simulations mimics the insertion of CH2 into a surface dimer as proposed in the standard growth model of diamond. For hydrocarbon species attached to two adjacent radical (biradical) sites, the MMC simulations give rise to significant changes in the bonding structure. For UNCD, the combinations of C3 and C3H2, and C3 and C4H2 (at diamond (100)2 × 1) and C and C2H2 (at diamond (111)1 × 1) are the most successful in nucleating new crystal layers. For NCD, the following combinations pursue the diamond structure the best: C2H2 and C3H2 (at diamond (100)2 × 1) and CH2 and C2H2 (at diamond (111)1 × 1). The different behaviors of the hydrocarbon species at the two diamond surfaces are related to the different sterical hindrances at the diamond surfaces.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.055
Times cited: 13
DOI: 10.1021/cg100063c
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“Understanding the surface diffusion processes during magnetron sputter-deposition of complex oxide Mg-Al-O thin films”. Georgieva V, Voter AF, Bogaerts A, Crystal growth &, design 11, 2553 (2011). http://doi.org/10.1021/cg200318h
Abstract: It is known that film structure may change dramatically with the extent of surface diffusion during the film growth process. In the present work, surface diffusion, induced thermally or activated by energetic impacts, is investigated theoretically under conditions appropriate for magnetron sputter-deposition of MgAlO thin films with varying stoichiometry. The distribution of surface diffusion energy barriers available to the system was determined for each stoichiometry, which allowed assessing in a qualitative way how much surface diffusion will take place on the time scale available between deposition events. The activation energy barriers increase with the Al concentration in the film, and therefore, the surface diffusion rates in the time frame of typical deposition rates drop, which can explain the decrease in crystallinity in the film structure and the transition to amorphous structure. The deposition process and the immediate surface diffusion enhanced by the energetic adatoms are simulated by means of a molecular dynamics model. The longer-time thermal surface diffusion and the energy landscape are studied by the temperature accelerated dynamics method, applied in an approximate way. The surface diffusion enhanced by the energetic impacts appears to be very important for the film structure in the low-temperature deposition regime.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.055
Times cited: 14
DOI: 10.1021/cg200318h
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