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Deposition of Cu nanoclusters produced by compact gas aggregation nanocluster source without size filtration is investigated. The main emphasis is given to the determination of influence of operating conditions (pressure in the ag...
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Deposition of Cu nanoclusters produced by compact gas aggregation nanocluster source without size filtration is investigated. The main emphasis is given to the determination of influence of operating conditions (pressure in the aggregation and deposition chambers, magnetron current) on deposition rate of Cu nanoclusters as well as on the evaluation of their size distribution and chemical structure. Subsequently, possibility to employ this nanocluster source for fabrication of Cu nanodusters/plasma polymer multilayer nanocomposites was tested. It is shown that by step-by-step deposition of layers of Cu nanoclusters and plasma polymer it is possible to control not only amount of Cu nanoclusters incorporated into plasma polymer, but also roughness, wettability and optical properties of resulting coatings without affecting their surface chemical composition.
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PdPt catalysts with different morphologies and atomic ratios have been synthesized on native SiO2/Si and on proton exchange membranes. The combination of the gas aggregation source and magnetron sputtering techniques allows the fo...
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PdPt catalysts with different morphologies and atomic ratios have been synthesized on native SiO2/Si and on proton exchange membranes. The combination of the gas aggregation source and magnetron sputtering techniques allows the formation of quasi core-shell Pd0.97Pt0.03@Pt nanoclusters. Transmission electron microscopy and grazing incidence wide-angle x-ray scattering measurements of the Pd-rich core reveal a mean diameter of 4 nm and a face-centered cubic structure. The Pt shell around half of the Pd-rich core is formed by magnetron sputtering, and increases the nanocluster diameter (up to 10 nm) and the overall Pt content (up to 85%). Membranes coated by the PdPt core catalyst and PdPt@Pt catalyst (resulting in the formation of catalyst-coated membranes) are incorporated into fuel cells and their electrical characteristics are measured. The association of the two deposition techniques results in the formation of quasi core-shell PdPt@Pt nanoclusters, improving the start-up step of the fuel cell.
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Gas aggregation cluster source based on planar magnetron was used for deposition of fluorocarbon nanocluster films. The films possess a high roughness with a size of nanoclusters estimated to be about 30 nm in average. Their chemi...
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Gas aggregation cluster source based on planar magnetron was used for deposition of fluorocarbon nanocluster films. The films possess a high roughness with a size of nanoclusters estimated to be about 30 nm in average. Their chemical structure was found to resemble that of a conventional bulk polytetrafluoroethylene which was confirmed by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The fluorine to carbon elemental ratio was found to be 1.95 with 86% of CF_2 structural units. The deposited films revealed super-hydrophobic character with values of water contact angle reaching over 170°.
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Copper and titanium nanoclusters in Ar and in Ar+O_2 gas mixtures were prepared using a magnetron based gas aggregation cluster source designed for Ultra High Vacuum operation. A considerable influence of oxygen addition on the fo...
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Copper and titanium nanoclusters in Ar and in Ar+O_2 gas mixtures were prepared using a magnetron based gas aggregation cluster source designed for Ultra High Vacuum operation. A considerable influence of oxygen addition on the formation of clusters was observed even at oxygen-to-argon admixture levels of the order of 1:1000. A quadrupole mass filter determined nanocluster size distribution while the total deposition rate was determined by quartz crystal measurements.
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摘要 :
Copper and titanium nanoclusters in Ar and in Ar+O_2 gas mixtures were prepared using a magnetron based gas aggregation cluster source designed for Ultra High Vacuum operation. A considerable influence of oxygen addition on the fo...
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Copper and titanium nanoclusters in Ar and in Ar+O_2 gas mixtures were prepared using a magnetron based gas aggregation cluster source designed for Ultra High Vacuum operation. A considerable influence of oxygen addition on the formation of clusters was observed even at oxygen-to-argon admixture levels of the order of 1:1000. A quadrupole mass filter determined nanocluster size distribution while the total deposition rate was determined by quartz crystal measurements.
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The present paper reports on target erosion as one of the crucial parameters influencing the cluster size distribution. Size distributions of nanosized Cu clusters produced by a DC magnetron sputtering source during the lifetime o...
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The present paper reports on target erosion as one of the crucial parameters influencing the cluster size distribution. Size distributions of nanosized Cu clusters produced by a DC magnetron sputtering source during the lifetime of several different targets were monitored using a quadrupole mass filter. It is indicated that, during the target lifetime, cluster size distribution continuously shifts towards larger cluster sizes and becomes broader. After a certain operation time the cluster size distribution changes abruptly and the cluster formation is stopped. This happens much earlier than the point at which the erosion groove depth reaches the target thickness. It is suggested that a change in the mass spectra during the target lifetime is caused by the variation of the free metal atom density in the aggregation region. This may be due to the alteration of the sputtering yield. It is shown that the variation of the mass spectra correlates with the angular dependence of the sputtering yield.
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Emulating water oxidation catalyzed by the oxomanganese clusters in the photosynthetic apparatus of plants has been a long-standing scientific challenge. The use of manganese oxide films has been explored, but while they may be ca...
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Emulating water oxidation catalyzed by the oxomanganese clusters in the photosynthetic apparatus of plants has been a long-standing scientific challenge. The use of manganese oxide films has been explored, but while they may be catalytically active on the surface, their poor conductivity hinders their overall performance. We have approached this problem by using manganese oxide nanoparticles with sizes of 4, 6 and 8 nm, produced in a sputter-gas-aggregation source and soft-landed onto conducting electrodes. The mass loading of these catalytic particles was kept constant and corresponded to 45%-80% of a monolayer coverage. Measurements of the water oxidation threshold revealed that the onset potential decreases significantly with decreasing particle size. The final stoichiometry of the catalytically active nanoparticles, after exposure to air, was identified as predominantly MnO. The ability of such a sub-monolayer film to lower the reaction threshold implies that the key role is played by intrinsic size effects, i.e., by changes in the electronic properties and surface fields of the nanoparticles with decreasing size. We anticipate that this work will serve to bridge the knowledge gap between bulk thick film electrocatalysts and natural photosynthetic molecular-cluster complexes.
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Magnetron sputtering and gas aggregation sources are commonly used techniques for the preparation of metallic nanopartides. In this study we compare both of these techniques used for the production of thin Ag nanoparticle films fr...
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Magnetron sputtering and gas aggregation sources are commonly used techniques for the preparation of metallic nanopartides. In this study we compare both of these techniques used for the production of thin Ag nanoparticle films from the point of view of their morphology, topography and optical properties in dependence on the deposition time and substrate material. It is shown that in the case of sputter deposition, the morphology and optical properties of prepared films are dependent on the substrate material and deposition time and the resulting films are smooth with root-mean-square roughness 2 nm. By contrast, films produced using gas aggregation source are considerably rougher (root-mean-square roughness 12 nm) and consist of individual Ag nanoparticles. The deposition time affects in this case only the amount of nanoparticles on the surface and intensity of an anomalous absorption peak. (C) 2015 Elsevier B.V. All rights reserved.
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A simple and compact gas aggregation cluster and nanoparticle source based on a planar magnetron (Haberland type) without mass separation was characterized. Such source produces a beam of neutral, positively and negatively charged...
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A simple and compact gas aggregation cluster and nanoparticle source based on a planar magnetron (Haberland type) without mass separation was characterized. Such source produces a beam of neutral, positively and negatively charged particles that are dragged by a buffer gas expanding from the aggregation chamber. Sizes, speeds and charges of nanoparticles have been determined using a combination of TEM micrographs, electrostatic deflection setup and numeric modeling. The strong dependence of the velocity of the nanoparticles on their size was confirmed both experimentally and by modeling.
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Silver-based nanomaterials that exhibit antibacterial character are intensively studied as they represent promising weapon against multi-drug resistant bacteria. Equally important class of materials represent coatings that have hi...
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Silver-based nanomaterials that exhibit antibacterial character are intensively studied as they represent promising weapon against multi-drug resistant bacteria. Equally important class of materials represent coatings that have highly water repellent nature. Such materials may be used for fabrication of anti-fogging or self-cleaning surfaces. The aim of this study is to combine both of these valuable material characteristics. Antibacterial and highly hydrophobic Ag/C:F nanocomposite films were fabricated by means of gas aggregation source of Ag nanoparticles and sputter deposition of C:F matrix. The nanocomposite coatings had three-layer structure C:F base layer/Ag nanoparticles/C:F top layer. It is shown that the increasing number of Ag nanoparticles in produced coatings leads not only in enhancement of their antibacterial activity, but also causes substantial increase of their hydrophobicity. Under optimized conditions, the coatings are super-hydrophobic with water contact angle equal to 165. and are capable to induce 6-log reduction of bacteria presented in solution within 4 h.
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