Silver layers substrates

Fig. 4.56. Schematic diagram of a SERS-active substrate and the measurement arrangement. Alumina nanoparticles are deposited on a glass surface and produce the required roughness. A thin silver layer is evaporated on to the nanoparticles and serves for the enhancement. Organic molecules adsorbed on the silver surface can be detected by irradiation with a laser and collecting the Raman scattered light.

The pits are generally embossed into the substrate (polycarbonate or polymethylmethacrylate) layer by an injection-molding process, and are used to indicate whether a data bit is 0 or 1. An aluminum or silver layer provides a reflective surface, and is protected from corrosion and damage by a radiation-cured acrylate (lacquer) layer, onto which a label is usually printed.197... 

Fig. 5 Montage image combining an STM image of the Ag oxide structure (from bottom left) superimposed over the proposed oxide structure (from top right). The numbers, n = 1-5, correspond to the symmetrically different positions within the middle silver layer sandwiched between two O layers. Agi and Ag2 have metallic character, as they are exclusively bonded to silver atoms in the substrate below, whereas Ags, Ag4, and Ags are directly bonded to oxygen inside the oxide rings and are ionic in nature. Both Ag4 and Ags sites sit above threefold sites of the underlying (111) lattice atoms, whereas Ags occupies a top site. Reprinted with permission from Bocquet et at.. Journal of the American Chemical Society, 2003, 125, 3119. 2003, American Chemical Society.

When coated with 90 nm of gold, the substrates produced were found to provide consistent enhancement for up to 2 weeks after evaporation, when stored in a dessicator. Silver-coated substrates generally provided enhancement factors that were only consistent when used within 48 h after evaporation, due to oxide layer formation. In addition, gold is known to be markedly more biologically inert than... 

The carbon onions can be isolated from the metal substrate by thermal treatment The silver or copper evaporate in vacuo at temperatures above 850 °C to release the onions. EspedaUy when using a thin film of silver on a silica support, the nano-onions can easily be collected from the silica gel left after heating as there are virtually no interactions between them (Figure 4.12). If, on the other hand, sihcon or steel is employed as a support for the silver layer, a strong binding of... 

FIGURE 9.1 Scheme of screen-printing electrodes. Fabrication process of the sensor consisted of three steps including consecutive printing of the silver layer (b), carbon layer (c), and insulating layer (d) on the polyester substrate. The sensors were produced in sheets of 20 electrodes. 

To obtain a good adhesion of the silver layer on steel substrates, usually a thin silver layer is predeposited using a low silver content (0.5-2 gl ) and a high-current density. Applying this procedure, the formation of a cementation layer of... 

The occurance of defects and the orientation of the cry-< stallites both depend on the morphology and the substrate material. Highly oriented films with few growth anomalies can be achieved on smooth substrates with vacuum deposited metal layer, e.g. a silver layer /4/. 

Monolayers can be transferred onto many different substrates. Most LB depositions have been perfonned onto hydrophilic substrates, where monolayers are transferred when pulling tire substrate out from tire subphase. Transparent hydrophilic substrates such as glass [18,19] or quartz [20] allow spectra to be recorded in transmission mode. Examples of otlier hydrophilic substrates are aluminium [21, 22, 23 and 24], cliromium [9, 25] or tin [26], all in their oxidized state. The substrate most often used today is silicon wafer. Gold does not establish an oxide layer and is tlierefore used chiefly for reflection studies. Also used are silver [27], gallium arsenide [27, 28] or cadmium telluride wafer [28] following special treatment. 

---