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Metallic Films (metallic + film)

Distribution by Scientific Domains
Polymers and Materials Science40%

Selected Abstracts

Preparation of Metallic Films on Elastomeric Stamps and Their Application for Contact Processing and Contact Printing,

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2003
H. Schmid
Abstract The formation of permanent or reversible metallic patterns on a substrate has applications in microfabrication and analytical techniques. Here, we investigate how to metallize an elastomeric stamp, either for processing of a substrate mediated by the proximity between the metal on the stamp and an active layer on the substrate, or for contact printing of the metal from a stamp to a substrate. The stamps were made from poly(dimethylsiloxane) (PDMS) and were modified before metallizing them with Au by adding to or removing from their bulk mobile silicone residues, by oxidizing their surface with an O2 -plasma, by surface-fluorination via silanization, or by priming them with a Ti layer. The interplay between the adhesion of the different layers defines two categories of application: contact processing and contact printing. Contact processing corresponds to keeping the metal on the stamp after contacting a substrate; it is reversible and nondestructive, and useful to define transient electrical contacts or quench fluorescence on a surface, for example. Contact printing occurs when the metal on the stamp adheres to the printed surface. Contact printing can transfer a metal, layers of metals, or an oxide onto a substrate with submicrometer lateral resolution. The transfer can be total or localized to the regions of contact, depending on the morphology of the metal on the stamp and/or the surface chemistry of the substrate. [source]

Characterization of Silver Trimethylacetate Complexes with Tertiary Phosphines as CVD Precursors of Thin Silver Films,

CHEMICAL VAPOR DEPOSITION, Issue 1 2005
P. Piszczek
Abstract AgI complexes [Ag(O2CtBu)(PMe3)] (1) and [Ag(O2CtBu)(PEt3)] (2) were used as CVD precursors. Silver films between 30,nm and 100,nm were deposited from the above compounds using hot-wall and cold-wall CVD techniques on Si(111) and Si(100) substrates in the temperature range 180-220,°C, under the reactor pressure 1,3,mbar. Metallic films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM), and conductivity measurements. [source]

In situ deformation of thin films on substrates

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2009
Marc Legros
Abstract Metallic thin-film plasticity has been widely studied by using the difference between the coefficients of thermal expansion of the film and the underlying substrate to induce stress. This approach is commonly known as the wafer curvature technique, based on the Stoney equation, which has shown that thinner films have higher yield stresses. The linear increase of the film strength as a function of the reciprocal film thickness, down to a couple hundred nanometers, has been rationalized in terms of threading and interfacial dislocations. Polycrystalline films also show this kind of dependence when the grain size is larger than or comparable to the film thickness. In situ TEM performed on plan-view or cross-section specimens faithfully reproduces the stress state and the small strain levels seen by the metallic film during wafer curvature experiments and simultaneously follows the change in its microstructure. Although plan-view experiments are restricted to thinner films, cross-sectional samples where the film is reduced to a strip (or nanowire) on its substrate are a more versatile configuration. In situ thermal cycling experiments revealed that the dislocation/interface interaction could be either attractive or repulsive depending on the interfacial structure. Incoherent interfaces clearly act as dislocation sinks, resulting in a dislocation density drop during thermal cycles. In dislocation-depleted films (initially thin or annealed), grain boundaries can compensate for the absence of dislocations by either shearing the film similarly to threading dislocations or through fast diffusion processes. Conversely, dislocations are confined inside the film by image forces in the cases of epitaxial interfaces on hard substrates. To increase the amount of strain seen by a film, and to decouple the effects of stress and temperature, compliant substrates can also be used as support for the metallic film. The composite can be stretched at a given temperature using heating/cooling straining holders. Other in situ TEM methods that served to reveal scaling effects are also reviewed. Finally, an alternate method, based on a novel bending holder that can stretch metallic films on rigid substrates, is presented. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc. [source]

Magnetic field effects on the optical response of corrugated films: Voigt geometry

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2003
J. H. Jacobo-Escobar
Abstract Using the Rayleigh,Fano modal theory it is investigated the interaction of p -polarized light with the corrugated surface of a metallic film. Calculations of the magnetoreflectance in the presence of an external magnetic field in the Voigt configuration are carried out. Studies are performed on the nonreciprocity property and the coupling of the incident light with the surface magnetoplasmons. It is found that the calculated dispersion relation of the surface magnetoplasmons predicts the possible experimental excitation of such modes. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Characteristics of Voltammetric Determination and Speciation of Chromium , A Review

ELECTROANALYSIS, Issue 13 2009
Andrzej Bobrowski
Abstract This article reviews the voltammetric methods of chromium determination, including adsorptive and catalytic adsorptive stripping voltammetry at liquid mercury, metallic films, and modified carbon paste electrodes. The principle applications of the catalytic adsorptive stripping voltammetric method of chromium(VI) determination in the presence of DTPA and nitrate, most useful in the analysis of chromium traces and its speciation, is presented in detail. Special emphasis is put on the presentation and characterization of the voltammetric procedures which make it possible to conduction speciation studies of chromium(VI) in the presence of a great excess of chromium(III) and surfactants. This survey is based on 173 articles. [source]

Magnetic Control of Tubular Catalytic Microbots for the Transport, Assembly, and Delivery of Micro-objects

ADVANCED FUNCTIONAL MATERIALS, Issue 15 2010
Alexander A. Solovev
Abstract Recently a significant amount of attention has been paid towards the development of man-made synthetic catalytic micro- and nanomotors that can mimic biological counterparts in terms of propulsion power, motion control, and speed. However, only a few applications of such self-propelled vehicles have been described. Here the magnetic control of self-propelled catalytic Ti/Fe/Pt rolled-up microtubes (microbots) that can be used to perform various tasks such as the selective loading, transportation, and delivery of microscale objects in a fluid is shown; for instance, it is demonstrated for polystyrene particles and thin metallic films ("nanoplates"). Microbots self-propel by ejecting microbubbles via a platinum catalytic decomposition of hydrogen peroxide into oxygen and water. The fuel and surfactant concentrations are optimized obtaining a maximum speed of 275,µm,s,1 (5.5 body lengths per second) at 15% of peroxide fuel. The microbots exert a force of around 3.77,pN when transporting a single 5,µm diameter particle; evidencing a high propulsion power that allows for the transport of up to 60 microparticles. By the introduction of an Fe thin film into the rolled-up microtubes, their motion can be fully controlled by an external magnetic field. [source]

Nanocrystalline Electroplated Cu,Ni: Metallic Thin Films with Enhanced Mechanical Properties and Tunable Magnetic Behavior

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2010
Eva Pellicer
Abstract Nanocrystalline 3,µm thick Cu1,xNix (0.45,,,x,,,0.87) films are electrodeposited galvanostatically onto Cu/Ti/Si (100) substrates, from a citrate- and sulphate-based bath containing sodium lauryl sulphate and saccharine as additives. The films exhibit large values of reduced Young's modulus (173,<,Er,<,192,GPa) and hardness (6.4,<,H,<,8.2,GPa), both of which can be tailored by varying the alloy composition. The outstanding mechanical properties of these metallic films can be ascribed to their nanocrystalline nature,as evidenced by X-ray diffraction, transmission electron microscopy, and atomic force microscopy,along with the occurrence of stacking faults and the concomitant formation of intragranular nanotwins during film growth. Due to their nanocrystalline character, these films also show very low surface roughness (root mean square deviation of around 2,nm). Furthermore, tunable magnetic properties, including a transition from paramagnetic to ferromagnetic behavior, are observed when the Ni percentage is increased. This combination of properties, together with the simplicity of the fabrication method, makes this system attractive for widespread technological applications, including hard metallic coatings or magnetic micro/nano-electromechanical devices. [source]

In situ deformation of thin films on substrates

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2009
Marc Legros
Abstract Metallic thin-film plasticity has been widely studied by using the difference between the coefficients of thermal expansion of the film and the underlying substrate to induce stress. This approach is commonly known as the wafer curvature technique, based on the Stoney equation, which has shown that thinner films have higher yield stresses. The linear increase of the film strength as a function of the reciprocal film thickness, down to a couple hundred nanometers, has been rationalized in terms of threading and interfacial dislocations. Polycrystalline films also show this kind of dependence when the grain size is larger than or comparable to the film thickness. In situ TEM performed on plan-view or cross-section specimens faithfully reproduces the stress state and the small strain levels seen by the metallic film during wafer curvature experiments and simultaneously follows the change in its microstructure. Although plan-view experiments are restricted to thinner films, cross-sectional samples where the film is reduced to a strip (or nanowire) on its substrate are a more versatile configuration. In situ thermal cycling experiments revealed that the dislocation/interface interaction could be either attractive or repulsive depending on the interfacial structure. Incoherent interfaces clearly act as dislocation sinks, resulting in a dislocation density drop during thermal cycles. In dislocation-depleted films (initially thin or annealed), grain boundaries can compensate for the absence of dislocations by either shearing the film similarly to threading dislocations or through fast diffusion processes. Conversely, dislocations are confined inside the film by image forces in the cases of epitaxial interfaces on hard substrates. To increase the amount of strain seen by a film, and to decouple the effects of stress and temperature, compliant substrates can also be used as support for the metallic film. The composite can be stretched at a given temperature using heating/cooling straining holders. Other in situ TEM methods that served to reveal scaling effects are also reviewed. Finally, an alternate method, based on a novel bending holder that can stretch metallic films on rigid substrates, is presented. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc. [source]

Magnetically tunable microstrip linear resonator on polycrystalline ferrite substrate

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2007
Rajeev Pourush
Abstract A low cost conventional half-wave microstrip linear resonator has been designed at 2 GHz central frequency and fabricated photolithographically by depositing metallic films on prepared LiMnTi polycrystalline ferrite substrate. Resonator characteristics have been examined by keeping it in the low biasing magnetic field values (from 0 to 298 Guass) applied in transverse direction of wave propagation and normal to ground plane. Tunability of 339 MHz (17%) was achieved which is the best reported so far for such a structure for low magnetic field values with a minimum insertion loss of 10.68 dB. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2868,2870, 2007; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.22858 [source]

Fabrication of 2-D nanostructures via metal deposition through a colloidal mask: comparison between thermal evaporation and RF magnetron sputtering

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2008
Magdalena Ulmeanu
Abstract We use spherical polystyrene beads in the size range from 500 nm - 2 ,m to form lithographic masks on surfaces. The masks consist of hexagonally arranged monolayers of these particles formed independently via a self-organized process upon solvent evaporation. With the help of the so called floating technique, the masks can be transferred to almost any arbitrary substrate. They have been utilized e.g. as masks for vacuum deposition, ion etching, or as masters for micro-contact-printing. Current research concentrates on the structure differences when the film deposition was done by thermal evaporation or RF magnetron sputtering. Investigations have been done on different metallic films, with emphasizes on Au thin film. The structures were investigated by atomic force microscopy (AFM) and scanning force microscopy (SEM). The differences in the nanostructures obtained after the removal of the colloidal mask will be evaluated in respect with the thin film deposition technique. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]