Influence of scale, geometry, and microstructure on the electrical properties of chemically deposited thin silver films
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Date
2007-12
Authors
Peterson, Sarah M., 1975-
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
Silver films with nanoscale to mesoscale thicknesses were produced by chemical reduction onto silica substrates and their physical and electrical properties were investigated and characterized. The method of silver deposition was developed in the context of this research and uses a single step reaction to produce consistent silver films on both flat silica coverslips and silica nanospheres of 250-1000 nm. Both the structure and the electrical properties of the silver films are found to differ significantly from those produced by vacuum deposition. Chemically deposited (CD) silver is not uniformly smooth, but rather is granular and porous with a network-like structure. By quantitatively accounting for the differences in scale, geometry, and microstructure of the CD films, it is found that the same models used to describe the resistivity of vacuum deposited films may be applied to CD films. A critical point in the analysis that allows this relation involves the definition of a geometric parameter, g, which replaces the thickness, t, as the critical length that influences the electrical properties of the film. The temperature dependent properties of electrical transport were also investigated and related to the microstructure of the CD films. A detailed characterization of CD silver as shells on silica spheres is also presented including physical and optical properties. In spite of the rough and porous morphology of the shells, the plasmon resonance of the core-shell structure is determined by the overall spherical shell structure and is tunable through variations in the shell thickness. Preliminary investigations into the electrical transport properties of aggregates of silver coated spheres suggest similarities in the influence scale, geometry, and microstructure to silver films on flat substrates. The aggregates of shells also exhibit pressure related resistance behavior due to the composite structure.
Description
xv, 101 p. ; ill. (some col.) A print copy of this title is available through the UO Libraries under the call number: KNIGHT QC176.84.E5 P47 2007
Keywords
Chemistry, Metallic films, Thin films, Thin films -- Electric properties, Microstructure, Electroless deposition, Resistivity, Nanoshells, Silver, Thin metal films