Surface-enhanced Raman scattering (SERS) efficiency of silver nanoparticles formed by laser irradiation or thermal annealing in sputtered silver oxide layers was examined. Silver nanoparticles formed by irradiation of He-Ne laser light (632.8 nm) to a sputtered silver oxide thin film thermally annealed at 300°C show good SERS, while silver nanoparticles formed by thermal annealing at 600°C scarcely show SERS. From these results, it is deduced that thermal annealing at a proper temperature results in formation of silver nuclei that can be precursors of silver nanoparticles with desirable sizes to induce the SERS, while thermal annealing at a higher temperature results in the formation of large silver particles that no longer cause the SERS.

This work encompasses a comparative analysis of the properties of two optical biosensor platforms: (1) the propagating surface plasmon resonance (SPR) sensor based on a planar, thin film gold surface and (2) the localized surface plasmon resonance (LSPR) sensor based on surface confined Ag nanoparticles fabricated by nanosphere lithography. The binding of Concanavalin A (ConA) to mannose-functionalized self-assembled monolayers (SAMs) is chosen to illustrate the similarities and the differences of these sensors. A comprehensive set of non-specific binding studies demonstrate that the single transduction mechanism is due to the specific binding of ConA to the mannose-functionalized surface. Finally, an elementary (2x1) multiplexed version of a LSPR carbohydrate sensing chip to probe the simultaneous binding of ConA to mannose and galactose-functionalized SAMs is also demonstrated.

Gas phase ammonolysis of volatile metal chlorides at elevated temperatures is a favorable way to produce nitride or oxynitride nanopowders. Their composition as well as the physico-chemical properties is determined by reaction temperature, molar ratio of the reactants and the residence time of the gases in the reaction zone. Both single and multi component powders can be obtained. Typical particle sizes are in the range of 50 to 350 nm. The specific surface can reach values up to 300 m2/g. Microporous analysis revealed the presence of pores with a diameter between 0.6 and 0.7 nm in amorphous silicon nitride. The powders can be used, depending on the characteristics, as catalyst or basic catalyst support. The paper gives an overview about vapor phase synthesis of single and multi component nitrides as well as the use of amorphous silicon nitride as a basic catalyst support for dehydrogenation of propane.

Miniaturized electronic noses to rapidly detect and differentiate trace amount of chemical agents are extremely attractive. Use of tin oxide nanoparticles as sensing elements has been proved to significantly improve both the response time and the sensitivity of gas sensors or electronic noses. In this paper, we report the synthesis of pure tin oxide nanoparticles using a simple, convenient, and low-cost mini-arc plasma source. The nanoparticle size distribution is measured online using a scanning electrical mobility spectrometer (SEMS). The product nanoparticles are analyzed ex-situ by high resolution transmission electron microscopy (HRTEM) for morphology, crystal structure, and defects. Non-agglomerated rutile tin oxide (SnO2) nanoparticles as small as a few nm have been produced, with rounded shapes and some faceting on the lowest energy surfaces.

Self assembled spheres of both Pt and Pt/Ru have been electrodeposited in a matrix of carbon black on a gold electrode. The spheres are roughly 200nm in diameter and have a high degree of surface porosity. As a fuel cell catalyst, the activity of the Pt/Ru toward methanol oxidation is the primary indication of performance. Catalysts deposited in the current limiting regime (i.e. low metal ion concentrations or more negative deposition potentials) show markedly higher oxidation current at 4.8-5.5mA as measured at +0.2V vs. saturated calomel electrode. Pt only deposits were also made and show identical morphology to Pt/Ru deposits. Surface area analysis of the Pt deposits correlate well with the oxidation activity of the Pt/Ru deposits, at similar deposition conditions. The maximum specific surface area measured for Pt, based on 100% coulombic efficiency, was about 35m2/g.

Gadolinium (Gd)- and gadolinium/magnesium (Gd/Mg)-films as well as top layers of catalytic films were prepared by rf-sputtering technique. To improve the optical properties, optical transparency, color and switching time, the Gd films were modified with Mg. By change of the sputtering parameters, the grain size of the Gd-films was varied in the range from 29 nm to 9.5 nm. To improve the catalytic properties, palladium-films (Pd) were modified with silver (Ag).

To investigate the influence of the structure and the microstructure on the optical and the switching properties of the films, X-ray diffraction measurements and scanning electron microscope studies were performed.

It is shown that the optical transmission of the GdH3 films can be improved by the modification of the gadolinium-films with magnesium. Further, a significant influence of the grain size is found. If the grains size of the films is reduced to 9.5 nm, the optical transmission of the films increases. The reduced grain size, leading to a larger inner surface, decreases the optical and the electrical switching time and the optical transmission. A reduction of the switching time is attained by the modification of the catalytic palladium films with silver.