“Purification of catalytically produced multi-wall nanotubes”. Colomer J-F, Piedigrosso P, Willems I, Journet C, Bernier P, Van Tendeloo G, Fonseca A, Nagy JB, Journal of the Chemical Society : Faraday transactions: physical chemistry and chemical physics 94, 3753 (1998). http://doi.org/10.1039/a806804f
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 92
DOI: 10.1039/a806804f
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“Adsorption of potassium and oxygen on graphite: a theoretical study”. Lamoen D, Persson BNJ, Journal Of Chemical Physics 108, 3332 (1998). http://doi.org/10.1063/1.475732
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 2.965
Times cited: 91
DOI: 10.1063/1.475732
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“Single chain elasticity and thermoelasticity of polyethylene”. Titantah JT, Pierleoni C, Ryckaert J-P, The journal of chemical physics 117, 9028 (2002). http://doi.org/10.1063/1.1514974
Abstract: Single-chain elasticity of polyethylene at theta point up to 90% of stretching with respect to its contour length is computed by Monte Carlo simulation of an atomistic model in continuous space. The elasticity law together with the free-energy and the internal energy variations with stretching are found to be very well represented by the wormlike chain model up to 65% of the chain elongation, provided the persistence length is treated as a temperature-dependent parameter. Beyond this value of elongation simple ideal chain models are not able to describe the Monte Carlo data in a thermodynamic consistent way. This study reinforces the use of the wormlike chain model to interpret experimental data on the elasticity of synthetic polymers in the finite extensibility regime, provided the chain is not yet in its fully stretched regime. Specific solvent effects on the elasticity law and the partition between energetic and entropic contributions to single chain elasticity are investigated. (C) 2002 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.965
Times cited: 5
DOI: 10.1063/1.1514974
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“Thermodynamic consistency and integral equations for the liquid structure”. Leys FE, March NH, Lamoen D, Journal Of Chemical Physics 117, 10726 (2002). http://doi.org/10.1063/1.1522377
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 2.965
DOI: 10.1063/1.1522377
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“Extension of the basis set of linearized augmented plane wave (LAPW) method by using supplemented tight binding basis functions”. Nikolaev AV, Lamoen D, Partoens B, The journal of chemical physics 145, 014101 (2016). http://doi.org/10.1063/1.4954962
Abstract: In order to increase the accuracy of the linearized augmented plane wave (LAPW) method, we present a new approach where the plane wave basis function is augmented by two different atomic radial components constructed at two different linearization energies corresponding to two different electron bands (or energy windows). We demonstrate that this case can be reduced to the standard treatment within the LAPW paradigm where the usual basis set is enriched by the basis functions of the tight binding type, which go to zero with zero derivative at the sphere boundary. We show that the task is closely related with the problem of extended core states which is currently solved by applying the LAPW method with local orbitals (LAPW+LO). In comparison with LAPW+LO, the number of supplemented basis functions in our approach is doubled, which opens up a new channel for the extension of the LAPW and LAPW+LO basis sets. The appearance of new supplemented basis functions absent in the LAPW+LO treatment is closely related with the existence of the ul-component in the canonical LAPW method. We discuss properties of additional tight binding basis functions and apply the extended basis set for computation of electron energy bands of lanthanum (face and body centered structures) and hexagonal close packed lattice of cadmium. We demonstrate that the new treatment gives lower total energies in comparison with both canonical LAPW and LAPW+LO, with the energy difference more pronounced for intermediate and poor LAPW basis sets.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 2.965
Times cited: 11
DOI: 10.1063/1.4954962
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“Quantitative morphometric analysis of single gold nanoparticles by optical extinction microscopy: Material permittivity and surface damping effects”. Payne LM, Masia F, Zilli A, Albrecht W, Borri P, Langbein W, Journal Of Chemical Physics 154, 044702 (2021). http://doi.org/10.1063/5.0031012
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.965
DOI: 10.1063/5.0031012
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“Conformational analysis of TMC114, a novel HIV-1 protease inhibitor”. Nivesanond K, Peeters A, Lamoen D, van Alsenoy C, Journal of Chemical Information and Modeling 48, 99 (2008). http://doi.org/10.1021/ci7001318
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.76
Times cited: 13
DOI: 10.1021/ci7001318
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“Direct room-temperature synthesis of methyl-functionalized Ti-MCM-41 nanoparticles and their catalytic performance in epoxidation”. Lin K, Pescarmona PP, Houthoofd K, Liang D, Van Tendeloo G, Jacobs PA, Journal of catalysis 263, 75 (2009). http://doi.org/10.1016/j.jcat.2009.01.013
Abstract: Methyl-functionalized Ti-MCM-41 nanoparticles with a size of 80 to 160 nm (Me-Ti-MCM-41 NP) were directly prepared via a dilute solution route by the co-condensation of tetraethoxysilane and methylalkoxysilanes in sodium hydroxide medium at room temperature. The characterization results showed the existence of ordered hexagonal mesoporous structure and tetrahedral Ti species in the nanoparticles. In the epoxidation of cyclohexene with tert-butyl hydroperoxide and aqueous H2O2, Me-Ti-MCM-41 NP samples displayed higher turnover frequencies (TOFs) for cyclohexene and initial reaction rates compared to Ti-MCM-41 and methyl-functionalized Ti-MCM-41 with normal particle size and to non-functionalized Ti-MCM-41 nanoparticles. Simultaneously, a higher selectivity for cyclohexene epoxide was observed in the case of aqueous H2O2, suggesting that the hydrolysis of cyclohexene epoxide with water is reduced on Me-Ti-MCM-41 NP samples. The improved catalytic behavior of Me-Ti-MCM-41 NP is discussed both in terms of the nanosize and methylation of the surface of the catalyst particles. The regeneration of Me-Ti-MCM-41 NP with tert-butyl hydroperoxide solution was evaluated via washing and calcination approaches.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 89
DOI: 10.1016/j.jcat.2009.01.013
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“Molecular shape-selectivity of MFI zeolite nanosheets in n-decane isomerization and hydrocracking”. Verheyen E, Jo C, Kurttepeli M, Vanbutsele G, Gobechiya E, Korányi TI, Bals S, Van Tendeloo G, Ryoo R, Kirschhock CEA, Martens JA;, Journal of catalysis 300, 70 (2013). http://doi.org/10.1016/j.jcat.2012.12.017
Abstract: MFI zeolite nanosheets with thickness of 2 and 8 nm were synthesized, transformed into bifunctional catalysts by loading with platinum and tested in n-decane isomerization and hydrocracking. Detailed analysis of skeletal isomers and hydrocracked products revealed that the MFI nanosheets display transition-state shape-selectivity similar to bulk MFI zeolite crystals. The suppressed formation of bulky skeletal isomers and C5 cracking products are observed both in the nanosheets and the bulk crystals grown in three dimensions. This is typical for restricted transition-state shape-selectivity, characteristic for the MFI type pores. It is a first clear example of transition-state shape-selectivity inside a zeolitic nanosheet. Owing to the short diffusion path across the sheets, expression of diffusion-based discrimination of reaction products in the MFI nanosheets was limited. The 2-methylnonane formation among monobranched C10 isomers and 2,7-dimethyloctane among dibranched C10 isomers, which in MFI zeolite are favored by product diffusion, was much less favored on the nanosheets compared to the reference bulk ZSM-5 material.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 121
DOI: 10.1016/j.jcat.2012.12.017
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“Pd-zeolites as heterogeneous catalysts in heck chemistry”. Dams M, Drijkoningen L, Pauwels B, Van Tendeloo G, de Vos DE, Jacobs PA, Journal of catalysis 209, 225 (2002). http://doi.org/10.1006/jcat.2002.3630
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 157
DOI: 10.1006/jcat.2002.3630
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“Selectivity in sorption and hydrogenation of methyl oleate and elaidate on MFI zeolites”. Philippaerts A, Paulussen S, Turner S, Lebedev OI, Van Tendeloo G, Poelman H, Bulut M, de Clippel F, Smeets P, Sels B, Jacobs P, Journal of catalysis 270, 172 (2010). http://doi.org/10.1016/j.jcat.2009.12.022
Abstract: Different zeolites were tested for selective removal of methyl elaidate (trans isomer) from an equimolar mixture with methyl oleate (cis isomer). Sorption experiments of the geometric isomers show that only ZSM-5 samples with reduced Al content in the framework are able to discriminate among the bent cis and the linear trans fatty acid methyl esters. Hydrogenation experiments of equimolar methyl oleate and elaidate mixtures at low temperature (65 °C) and high hydrogen pressure (6.0 MPa), using Pt catalysts, confirm this result. Only with a Pt/NaZSM-5 catalyst outspoken selectivity for the hydrogenation of the trans isomer is obtained. In order to prepare a selective Pt/ZSM-5 catalyst, the influence of Pt addition (impregnation, ion-exchange and competitive ion-exchange) and Pt activation (different calcination and reduction temperatures) on the Pt-distribution and Pt particle size was investigated using SEM, bright-field and HR TEM, EDX, electron tomography, CO-chemisorption, XPS, XRD, and UVvis measurements. The best result in terms of hydrogenation activity and selectivity is obtained with a Pt/ZSM-5 catalyst, which is prepared via competitive ion-exchange, followed by slow calcination up to 350 °C under high O2 flow and a reduction up to 500 °C under H2. This preparation method leads to a Pt/ZSM-5 catalyst with the best Pt distribution and the smallest Pt clusters occluded in the zeolite structure. Finally, the influence of zeolite crystal size, morphology, and elemental composition of ZSM-5 on hydrogenation activity and selectivity was investigated in detail.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 24
DOI: 10.1016/j.jcat.2009.12.022
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“Synthesis and catalytic activity of Ti-MCM-41 nanoparticles with highly active titanium sites”. Lin K, Pescarmona PP, Vandepitte H, Liang D, Van Tendeloo G, Jacobs PA, Journal of catalysis 254, 64 (2008). http://doi.org/10.1016/j.jcat.2007.11.017
Abstract: Ti-MCM-41 nanoparticles 80-160 nm in diameter (Ti-MCM-41 NP) were successfully prepared by a dilute solution route in sodium hydroxide medium at ambient temperature. Ti-MCM-41 NP were characterized by X-ray diffraction, nitrogen adsorption/desorption isotherms, SEM, TEM. FT-IR, and UV-vis spectroscopy. The characterization results showed the existence of highly ordered hexagonal mesoporous structure and tetrahedral Ti species in Ti-MCM-41 NP. In the epoxidation of cyclohexene with aqueous H2O2, Ti-MCM-41 NP displayed higher conversion and initial reaction rate than a Ti-MCM-41 sample with normal particle size (Ti-MCM-41 LP). Diffusion of the reactants was accelerated and the accessibility to the catalytic Ti species was enhanced in the shorter channels in Ti-MCM-41 NP samples. Ti-MCM-41 NP showed much higher selectivity for cyclohexene oxide compared with Ti-MCM-41 LP, suggesting reduced hydrolysis of cyclohexene oxide with water in the former case. The increased selectivity for cyclohexene oxide can be attributed to the lower concentration of residual surface silanols in Ti-MCM-41 NP and the shorter residence time of epoxide in the shorter mesoporous channels. Ti-MCM-41 NP also appears to be a suitable catalyst in the epoxidation of a bulky substrate, like cholesterol, with tert-butyl hydroperoxide. (c) 2007 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 52
DOI: 10.1016/j.jcat.2007.11.017
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“A MoVI grafted metal organic framework : synthesis, characterization and catalytic investigations”. Leus K, Liu Y-Y, Meledina M, Turner S, Van Tendeloo G, van der Voort P, Journal of catalysis 316, 201 (2014). http://doi.org/10.1016/j.jcat.2014.05.019
Abstract: We present the post-modification of a gallium based Metal Organic Framework, COMOC-4, with a Mo-complex. The resulting Mo@COMOC-4 was characterized by means of N2 sorption, XRPD, DRIFT, TGA, XRF, XPS and TEM analysis. The results demonstrate that even at high Mo-complex loadings on the framework, no aggregation or any Mo or Mo oxide species are formed. Moreover, the Mo@COMOC-4 was evaluated as a catalyst in the epoxidation of cyclohexene, cyclooctene and cyclododecene employing TBHP in decane as oxidant. The post-modified COMOC-4 exhibits a very high selectivity toward the epoxide (up to 100%). Regenerability and stability tests have been carried out demonstrating that the catalyst can be recycled without leaching of Mo or loss of crystallinity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 36
DOI: 10.1016/j.jcat.2014.05.019
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“Quantitative determination of residual silver distribution in nanoporous gold and its influence on structure and catalytic performance”. Mahr C, Kundu P, Lackmann A, Zanaga D, Thiel K, Schowalter M, Schwan M, Bals S, Wittstock A, Rosenauer A, Journal of catalysis 352, 52 (2017). http://doi.org/10.1016/j.jcat.2017.05.002
Abstract: Large efforts have been made trying to understand the origin of the high catalytic activity of dealloyed nanoporous gold as a green catalyst for the selective promotion of chemical reactions at low temperatures. Residual silver, left in the sample after dealloying of a gold-silver alloy, has been shown to have a strong influence on the activity of the catalyst. But the question of how the silver is distributed within the porous structure has not finally been answered yet. We show by quantitative energy dispersive X-ray tomography measurements that silver forms clusters that are distributed irregularly, both on the surface and inside the ligaments building up the porous structure. Furthermore, we find that the role of the residual silver is ambiguous. Whereas CO oxidation is supported by more residual silver, methanol oxidation to methyl formate is hindered. Structural characterisation reveals larger ligaments and pores for decreasing residual silver concentration.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 42
DOI: 10.1016/j.jcat.2017.05.002
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“Nano-single crystal coalesced PtCu nanospheres as robust bifunctional catalyst for hydrogen evolution and oxygen reduction reactions”. Li W, Hu Z-Y, Zhang Z, Wei P, Zhang J, Pu Z, Zhu J, He D, Mu S, Van Tendeloo G, Journal of catalysis 375, 164 (2019). http://doi.org/10.1016/J.JCAT.2019.05.031
Abstract: Because of high electrocatalytic activity, Pt based metal nanospheres (NSs) have attracted a lot of attention. Hence, multi-particle nano-single crystal coalesced PtCu NSs are designed and successfully synthesized by a cost-effective aqueous solution method. The formed PtCu NS catalyst exhibits a superior hydrogen evolution reaction (HER) electrocatalytic activity with an ultralow onset potential of 18 mV at the current density of 2 mA/cm(2) and high mass activity of 1.08 A/mg(pt) (7.2 times higher than that of commercial Pt/C catalysts). Also, it shows an enhancement of 3.2 and 2.7 times in the mass and specific activities toward oxygen reduction reaction (ORR) compared to that of Pt/C. Moreover, it possesses an excellent catalytic durability for both ORR and HER. Even after 10,000 cycles, its ORR mass activity retains 87% of its initial value. The density functional theory (DFT) calculations demonstrate that by introducing Cu atoms into the Pt lattice, a downshift of the D-band center and favorable hydrogen adsorption free energy of approaching to zero (Delta G) occur, indicating the increased electrocatalytic activity of Pt electrocatalysts. (C) 2019 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 25
DOI: 10.1016/J.JCAT.2019.05.031
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“Highly active, selective, and stable Pd single-atom catalyst anchored on N-doped hollow carbon sphere for electrochemical H₂O₂, synthesis under acidic conditions”. Xi J, Yang S, Silvioli L, Cao S, Liu P, Chen Q, Zhao Y, Sun H, Hansen JN, Haraldsted J-PB, Kibsgaard J, Rossmeisl J, Bals S, Wang S, Chorkendorff I, Journal Of Catalysis 393, 313 (2021). http://doi.org/10.1016/J.JCAT.2020.11.020
Abstract: Single-atom catalysts (SACs) have recently attracted broad scientific interests due to their unique structural feature, the single-atom dispersion. Optimized electronic structure as well as high stability are required for single-atom catalysts to enable efficient electrochemical production of H2O2. Herein, we report a facile synthesis method that stabilizes atomic Pd species on the reduced graphene oxide/Ndoped carbon hollow carbon nanospheres (Pd1/N-C). Pd1/N-C exhibited remarkable electrochemical H2O2 production rate with high faradaic efficiency, reaching 80%. The single-atom structure and its high H2O2 production rate were maintained even after 10,000 cycle stability test. The existence of single-atom Pd as well as its coordination with N species is responsible for its high activity, selectivity, and stability. The N coordination number and substrate doping around Pd atoms are found to be critical for an optimized adsorption energy of intermediate *OOH, resulting in efficient electrochemical H2O2 production. (C) 2020 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.844
Times cited: 40
DOI: 10.1016/J.JCAT.2020.11.020
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“Sustainable formation of tricarballylic acid from citric acid over highly stable Pd/Nb2O5.nH2O catalysts”. Stuyck W, Bugaev AL, Nelis T, de Oliveira-Silva R, Smolders S, Usoltsev OA, Arenas Esteban D, Bals S, Sakellariou D, De Vos D, Journal of catalysis (2022). http://doi.org/10.1016/j.jcat.2022.02.013
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 7.3
Times cited: 5
DOI: 10.1016/j.jcat.2022.02.013
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“Ab initio study of shallow acceptors in bixbyite V2O3”. Sarmadian N, Saniz R, Partoens B, Lamoen D, Journal of applied physics 117, 015703 (2015). http://doi.org/10.1063/1.4905316
Abstract: We present the results of our study on p-type dopability of bixbyite V2O3 using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) within the density functional theory (DFT) formalism. We study vanadium and oxygen vacancies as intrinsic defects and substitutional Mg, Sc, and Y as extrinsic defects. We find that Mg substituting V acts as a shallow acceptor, and that oxygen vacancies are electrically neutral. Hence, we predict Mg-doped V2O3 to be a p-type conductor. Our results also show that vanadium vacancies are relatively shallow, with a binding energy of 0.14 eV, so that they might also lead to p-type conductivity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 3
DOI: 10.1063/1.4905316
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“Anisotropic magnetism and spin-dependent transport in Co nanoparticle embedded ZnO thin films”. Li DY, Zeng YJ, Pereira LMC, Batuk D, Hadermann J, Zhang YZ, Ye ZZ, Temst K, Vantomme A, Van Bael MJ, Van Haesendonck C;, Journal of applied physics 114, 033909 (2013). http://doi.org/10.1063/1.4815877
Abstract: Oriented Co nanoparticles were obtained by Co ion implantation in crystalline ZnO thin films grown by pulsed laser deposition. Transmission electron microscopy revealed the presence of elliptically shaped Co precipitates with nanometer size, which are embedded in the ZnO thin films, resulting in anisotropic magnetic behavior. The low-temperature resistance of the Co-implanted ZnO thin films follows the Efros-Shklovskii type variable-range-hopping. Large negative magnetoresistance (MR) exceeding 10% is observed in a magnetic field of 1 T at 2.5K and the negative MR survives up to 250K (0.3%). The negative MR reveals hysteresis as well as anisotropy that correlate well with the magnetic properties, clearly demonstrating the presence of spin-dependent transport. (C) 2013 AIP Publishing LLC.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 10
DOI: 10.1063/1.4815877
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“Bond length variation in Ga1-xInxAs crystals from the Tersoff potential”. Titantah JT, Lamoen D, Schowalter M, Rosenauer A, Journal of applied physics 101, 123508 (2007). http://doi.org/10.1063/1.2748338
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 19
DOI: 10.1063/1.2748338
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“Circular dichroism in the electron microscope: progress and applications (invited)”. Schattschneider P, Ennen I, Stoger-Pollach M, Verbeeck J, Journal of applied physics 107, 09d311 (2010). http://doi.org/10.1063/1.3365517
Abstract: According to theory, x-ray magnetic circular dichroism in a synchrotron is equivalent to energy loss magnetic chiral dichroism (EMCD) in a transmission electron microscope (TEM). After a synopsis of the development of EMCD, the theoretical background is reviewed and recent results are presented, focusing on the study of magnetic nanoparticles for ferrofluids and Heusler alloys for spintronic devices. Simulated maps of the dichroic strength as a function of atom position in the crystal allow evaluating the influence of specimen thickness and sample tilt on the experimental EMCD signal. Finally, the possibility of direct observation of chiral electronic transitions with atomic resolution in a TEM is discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 28
DOI: 10.1063/1.3365517
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“Distribution of fields and charge carriers in cylindrical nanosize silicon-based metal-oxide-semiconductor structures”. Pokatilov EP, Fomin VM, Balaban SN, Gladilin VN, Klimin SN, Devreese JT, Magnus W, Schoenmaker W, Collaert N, van Rossum M, de Meyer K, Journal Of Applied Physics 85, 6625 (1999). http://doi.org/10.1063/1.370171
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 2.068
Times cited: 16
DOI: 10.1063/1.370171
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“Effect of high temperature deposition on CoSi2 phase formation”. Comrie CM, Ahmed A, Smeets D, Demeulemeester J, Turner S, Van Tendeloo G, Detavernier C, Vantomme A, Journal of applied physics 113, 234902 (2013). http://doi.org/10.1063/1.4811352
Abstract: This paper discusses the nucleation behaviour of the CoSi to CoSi2 transformation from cobalt silicide thin films grown by deposition at elevated substrate temperatures ranging from 375 °C to 600 °C. A combination of channelling, real-time Rutherford backscattering spectrometry, real-time x-ray diffraction, and transmission electron microscopy was used to investigate the effect of the deposition temperature on the subsequent formation temperature of CoSi2, its growth behaviour, and the epitaxial quality of the CoSi2 thus formed. The temperature at which deposition took place was observed to exert a significant and systematic influence on both the formation temperature of CoSi2 and its growth mechanism. CoSi films grown at the lowest temperatures were found to increase the CoSi2 nucleation temperature above that of CoSi2 grown by conventional solid phase reaction, whereas the higher deposition temperatures reduced the nucleation temperature significantly. In addition, a systematic change in growth mechanism of the subsequent CoSi2 growth occurs as a function of deposition temperature. First, the CoSi2 growth rate from films grown at the lower reactive deposition temperatures is substantially lower than that grown at higher reactive deposition temperatures, even though the onset of growth occurs at a higher temperature, Second, for deposition temperatures below 450 °C, the growth appears columnar, indicating nucleation controlled growth. Elevated deposition temperatures, on the other hand, render the CoSi2 formation process layer-by-layer which indicates enhanced nucleation of the CoSi2 and diffusion controlled growth. Our results further indicate that this observed trend is most likely related to stress and changes in microstructure introduced during reactive deposition of the CoSi film. The deposition temperature therefore provides a handle to tune the CoSi2 growth mechanism.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 2
DOI: 10.1063/1.4811352
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“Effect of PbZr0.52Ti0.48O3 thin layer on structure, electronic and magnetic properties of La0.65Sr0.35MnO3 and La0.65Ca0.30MnO3 thin-films”. Hezareh T, Razavi FS, Kremer RK, Habermeier H-U, Lebedev OI, Kirilenko D, Van Tendeloo G, Journal of applied physics 109, 113707 (2011). http://doi.org/10.1063/1.3592660
Abstract: Epitaxial thin film heterostructures of high dielectric PbZr<sub>1-x</sub>Ti<sub>x</sub>O<sub>3</sub> (PZT) and La<sub>1-x</sub>A<sub>x</sub>MnO<sub>3</sub> (A-divalent alkaline earth metals such as Sr (LSMO) and Ca (LCMO)) were grown on SrTiO<sub>3</sub> substrates and their structure, temperature dependence of electrical resistivity, and magnetization were investigated as a function of the thickness of the LSMO(LCMO) layer. The microstructures of the samples were analyzed by TEM. By applying an electric field across the PZT layer, we applied a ferrodistortive pressure on the manganite layer and studied the correlations between lattice distortion and electric transport and magnetic properties of the CMR materials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 4
DOI: 10.1063/1.3592660
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“Enhancement of second harmonic generation signal in thermally poled glass ceramic with NaNbO3 nanocrystals”. Malakho A, Fargin E, Lahaye M, Lazoryak B, Morozov V, Van Tendeloo G, Rodriguez V, Adamietz F, Journal of applied physics 100, 063103 (2006). http://doi.org/10.1063/1.2259816
Abstract: Glass ceramic composites were prepared by bulk crystallization of NaNbO3 in sodium niobium borate glasses. A homogeneous bulk crystallization of the NaNbO3 phase takes place during heat treatments that produces visible-near infrared transparent materials with similar to 30 nm NaNbO3 nanocrystallites. Upon thermal poling, a strong Na+ depleted nonlinear optical thin layer is observed at the anode side that should induce a large internal static electric field. In addition, the chi((2)) response of the poled glass ceramic composites increases from 0.2 up to 1.9 pm/V with the rate of crystallization. Two mechanisms may be considered: a pure structural chi((2)) process connected with the occurrence of a spontaneous ferroelectric polarization or an increase of the chi((3)) response of the nanocrystallites that enhances the electric field induced second harmonic generation process. (c) 2006 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 13
DOI: 10.1063/1.2259816
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“First-principles study of carbon impurities in CuInSe2 and CuGaSe2, present in non-vacuum synthesis methods”. Bekaert J, Saniz R, Partoens B, Lamoen D, Journal of applied physics 117, 015104 (2015). http://doi.org/10.1063/1.4905538
Abstract: A first-principles study of the structural and electronic properties of carbon impurities in CuInSe2 and CuGaSe2 is presented. Carbon is present in organic molecules in the precursor solutions used in non-vacuum growth methods for CuInSe2 and CuGaSe2 based photovoltaic cells. These growth methods make more efficient use of material, time, and energy than traditional vacuum methods. The formation energies of several carbon impurities are calculated using the hybrid HSE06 functional. C Cu acts as a shallow donor, CIn and interstitial C yield deep donor levels in CuInSe2, while in CuGaSe2 CGa and interstitial C act as deep amphoteric defects. So, these defects reduce the majority carrier (hole) concentration in p-type CuInSe2 and CuGaSe2 by compensating the acceptor levels. The deep defects are likely to act as recombination centers for the photogenerated charge carriers and are thus detrimental for the performance of the photovoltaic cells. On the other hand, the formation energies of the carbon impurities are high, even under C-rich growth conditions. Thus, few C impurities will form in CuInSe2 and CuGaSe2 in thermodynamic equilibrium. However, the deposition of the precursor solution in non-vacuum growth methods presents conditions far from thermodynamic equilibrium. In this case, our calculations show that C impurities formed in non-equilibrium tend to segregate from CuInSe2 and CuGaSe2 by approaching thermodynamic equilibrium, e.g., via thorough annealing.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 6
DOI: 10.1063/1.4905538
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“High resolution electron microscopy study of molecular beam epitaxy grown CoSi2/Si1-xGex/Si(100) heterostructurs”. Buschmann V, Rodewald M, Fuess H, Van Tendeloo G, Schäffer C, Journal of applied physics 85, 2119 (1999). http://doi.org/10.1063/1.369512
Abstract: Two CoSi2/Si1-xGex/Si(100) heterostructures, with different Ge content, made by molecular beam epitaxy are characterized by high resolution electron microscopy. In general, the interface between the CoSi2 thin film and the Si1-xGex layer is of a high structural quality and the strained Si1-xGex layer exhibits few defects. For both samples, different interface structures are present, although the dominant interfacial configuration is similar to the unreconstructed interface present at the CoSi2/Si(100) interface. Only occasionally (2x1) reconstructed interface regions are found which are just a few nanometers in length. Phenomena such as Ge segregation and the introduction of defects are also observed in the Si1-xGex layer. We attribute the minimal presence of the reconstructed interface to both the (2x8):Si1-xGex(100) surface reconstruction and the Ge segregation that takes place. (C) 1999 American Institute of Physics. [S0021-8979(99)02104-0].
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 6
DOI: 10.1063/1.369512
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“Hydrogen impurities and native defects in CdO”. Amini MN, Saniz R, Lamoen D, Partoens B, Journal of applied physics 110, 063521 (2011). http://doi.org/10.1063/1.3641971
Abstract: We have used first-principles calculations based on density functional theory to study point defects in CdO within the local density approximation and beyond (LDA+U). Hydrogen interstitials and oxygen vacancies are found to act as shallow donors and can be interpreted as the cause of conductivity in CdO. Hydrogen can also occupy an oxygen vacancy in its substitutional form and also acts as a shallow donor. Similar to what was found for ZnO and MgO, hydrogen creates a multicenter bond with its six oxygen neighbors in CdO. The charge neutrality level for native defects and hydrogen impurities has been calculated. It is shown that in the case of native defects, it is not uniquely defined. Indeed, this level depends highly on the chemical potentials of the species and one can obtain different values for different end states in the experiment. Therefore, a comparison with experiment can only be made if the chemical potentials of the species in the experiment are well defined. However, for the hydrogen interstitial defect, since this level is independent of the chemical potential of hydrogen, one can obtain a unique value for the charge neutrality level. We find that the Fermi level stabilizes at 0.43 eV above the conduction band minimum in the case of the hydrogen interstitial defect, which is in good agreement with the experimentally reported value of 0.4 eV.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 13
DOI: 10.1063/1.3641971
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“In situ transmission electron microscopy study of Ni silicide phases formed on (001) Si active lines”. Teodorescu V, Nistor L, Bender H, Steegen A, Lauwers A, Maex K, van Landuyt J, Journal of applied physics 90, 167 (2001). http://doi.org/10.1063/1.1378812
Abstract: The formation of Ni silicides is studied by transmission electron microscopy during in situ heating experiments of 12 nm Ni layers on blanket silicon, or in patterned structures covered with a thin chemical oxide. It is shown that the first phase formed is the NiSi2 which grows epitaxially in pyramidal crystals. The formation of NiSi occurs quite abruptly around 400 degreesC when a monosilicide layer covers the disilicide grains and the silicon in between. The NiSi phase remains stable up to 800 degreesC, at which temperature the layer finally fully transforms to NiSi2. The monosilicide grains show different epitaxial relationships with the Si substrate. Ni2Si is never observed. (C) 2001 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 97
DOI: 10.1063/1.1378812
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“Influence of the morphology on the magneto-transport properties of laser-ablated ultrathin La0.7Ba0.3MnO3 films”. Das A, Gordon I, Wagner P, Cannaerts M, Moshchalkov VV, Bruynseraede Y, Schuddinck W, Van Tendeloo G, Borghs G, Journal of applied physics 90, 1429 (2001). http://doi.org/10.1063/1.1380217
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 2
DOI: 10.1063/1.1380217
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