Surface smoothing by energetic cluster impact

Rattunde, Oliver; Moseler, Michael; Häfele, A.; Kraft, Jürgen; Rieser, Daniel; Haberland, Hellmut

doi:10.1063/1.1398067

Cited by 39 publications

(14 citation statements)

References 15 publications

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“…The depositions were made in a few minutes, such that the density of the nanoparticles deposited on the substrates was not too high. In order to retain the structural and morphological properties, the energy of cluster impact 20,21 was controlled; the energy of acceleration was kept at 0.1 eV atom À1 , assuring a soft landing of the particles on the substrate.…”

Section: Methodsmentioning

confidence: 99%

Highly size-controlled synthesis of Au/Pd nanoparticles by inert-gas condensation

et al. 2008

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Gold/Palladium nanoparticles were fabricated by inert-gas condensation on a sputtering reactor. With this method, by controlling both the atmosphere on the condensation chamber and the magnetron power, it was possible to produce nanoparticles with a high degree of monodispersity in size. The structure and size of the Au/Pd nanoparticles were determined by mass spectroscopy, and confirmed by atomic force microscopy and electron transmission microscopy measurements. The chemical composition was analyzed by X-ray microanalysis. From these measurements we confirmed that with the sputtering technique we are able to produce particles of 1, 3, and 5 nm on size, depending on the choice of the synthesis conditions. From TEM measurements made both in the regular HREM, as well as in STEM-HAADF mode, we found that the particles are icosahedral in shape, and the micrographs show no evidence of a core-shell structure, in contrast to what is observed in the case of nanoparticles prepared by chemical synthesis.

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Section: Methodsmentioning

confidence: 99%

Highly size-controlled synthesis of Au/Pd nanoparticles by inert-gas condensation

et al. 2008

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“…7,8 In this technique, charged gold clusters are accelerated by an electric field onto the clean silicon substrate. The gold clusters are produced by a magnetron sputter discharge within a gas aggregation source.…”

Section: A Film Fabrication and Characterizationmentioning

confidence: 99%

Nanostructured gold films as broadband terahertz antireflection coatings

et al. 2008

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The potential of nanometer-thick, randomly nanostructured gold films as broadband wave impedancematching coatings for nondispersive substrates in the terahertz frequency range is demonstrated. Based on a wave impedance approach and the specific non-Drude conductivity of our films, we model the reflectivity at the coated interface between silicon and air and show that nanostructured films offer a considerably better broadband performance than conventional bulk metallic layers. The predictions from the theoretical model are verified in experimental studies of different gold nanostructures investigated by terahertz time-domain spectroscopy in the frequency range of 0.2-2.2 THz. An extension of a previously developed subgridding scheme for the finite-difference time-domain method allows us to simulate terahertz-pulse propagation through uncoated and coated samples and to follow attenuation and reshaping of the internally reflected pulse when the film thickness is varied with subnanometer precision.

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“…To keep a low density of nanoparticles, the depositions were made in just a few minutes. In order to preserve the structural and morphological properties, the energy of cluster impact 22,23 was controlled; the energy of acceleration was close to 0.1 eV/atom, which corresponds to a soft landing regime. 22,24 The morphological characterization of the particles was made by AFM analysis, using a Veeco CPII AFM system in contact mode.…”

Section: Experimental Methods and Theoretical Calculationsmentioning

confidence: 99%

On the Structure and Properties of Silver Nanoparticles

et al. 2008

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Silver tetrahedral nanoparticles (NP) were synthesized using the inert gas condensation technique. We performed morphological and optical characterization of the nanoparticles (NPs) using atomic force microscopy (AFM), mass spectroscopy (MS), and UV-visible spectroscopy. The Ag NPs were produced by modified magnetron sputtering, followed by thermalization and condensation in a high pressure zone. Along the synthesis process, the size of the NPs was controlled through the handling of the gas flow (Ar and He), the magnetron power, and the length of the aggregation zone. We optimized the synthesis parameters to obtain a peak on the size distribution of Ag NPs around of 5 nm (as measured with AFM and MS). The AFM measurements show that the particles have tetrahedral shape, with a fair correspondence with a 2925-atoms ideal tetrahedron. We performed a set of Molecular Dynamics (MD) calculations using the Embedded Atom potential model to simulate the dynamics of particles with different shapes, obtaining that, at sizes close to that of the particles produced experimentally, the tetrahedra may be as energetically stable as cuboctahedra of roughly the same size, and that their melting point is below but close to that of the bulk. We also found that both the size and shape of the nanoparticles determine the shift of the UV-visible absorption spectrum. Finally, we observed the formation of atomic islands above the faces of the Ag tetrahedral NPs, in agreement with the results obtained from the MD simulations.

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Surface smoothing by energetic cluster impact

Cited by 39 publications

References 15 publications

Highly size-controlled synthesis of Au/Pd nanoparticles by inert-gas condensation

Highly size-controlled synthesis of Au/Pd nanoparticles by inert-gas condensation

Nanostructured gold films as broadband terahertz antireflection coatings

On the Structure and Properties of Silver Nanoparticles

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