Metal scanning probe techniques

For overcoming the limit of light microscopy and further improvement in spatial resolution, the implementation of scaiuiing near-held microscopy (SNOM) by means of a local illumination probe is an interesting approach [33-35]. The method is based on the held enhancement in the cavity between a sharp metal dp and the sample. In combination with Raman spectroscopy, this scanning probe technique is called tip-enhanced Raman spectroscopy (TERS) and enables high-resolution spatial microscopy with a lateral resolution of 50 nm [35]. Bouhelier [36] has reviewed advances in this held. 

Summary. The potential of in-situ scanning probe techniques for the local investigation of surface properties and reactions at "nonideal" electrodes is presented in a typical example in the field of metal underpotential deposition, the essential role of the step dislocations for the local progress of adsorbate formation and also for the longterm adsorbate stability is shown and discussed for the adsorption of Pb and TI monolayers at stepped Ag(l 11) electrodes. 

Finally, scanning tunneling microscopy and spectroscopy (STM/STS) are scanned probe techniques based on the tunneling of electrons across an Angstrom-scale gap between a sample surface and a sharp metal tip electrically connected in a biased circuit. It can provide both geometric and electronic structure information. In contrast to LEED, it locally probes direct space for this information with atomic resolution. It is extremely surface sensitive compared to the other mentioned techniques, which sample information... 

Localized forms of corrosion (such as pitting, crevice, and galvanic corrosion) arise when the metal surface is not compositionally uniform and/or when there is not a uniform exposure of the metal surface to the corrosive environment [6], Such localized forms of corrosion lead to nonuniform current density distribution across the metal surface as well as nonuniform distribntions of species concentration (such as metal ions, H+, and Oj). For these localized forms of corrosion, the scanning probe techniques provide valuable spatial and temporal information not available from the surface-averaging (or global) techniques mentioned earlier. A brief review of scanning probe techniques as applied to localized corrosion studies has recently appeared [7]. We have recently prepared a very extensive review chapter for Volume 24 of Electroanalytical Chemistry A Series of Advances [8], and the reader is referred to that chapter for more in-depth discussion of the application of these techniques in corrosion research. In Section 14.2, we provide an overview of several scanning electrochemical probe techniques used in corrosion research. In Section 14.3, we describe... 

Mark A. Barteau is Robert L. Pigford Professor and Chair of the Department of Chemical Engineering at the University of Delaware. He received his B.S. degree from Washington University in 1976 and his M.S. (1977) and Ph.D. (1981) from Stanford University. His research area is chemical engineering with specialized interests in application of surface techniques to reactions on nonmetals, hydrocarbon and oxygenate chemistry on metals and metal oxides, scanning probe microscopies, and catalysis by metal oxides. 

Less generally applicable than electron or scanning probe microscopy, but capable of revealing great detail, are field emission and field ion microscopy (FEM and F1M). These techniques are limited to the investigation of sharp metallic tips, however, with the attractive feature that the facets of such tips exhibit a variety of crystallographically different surface orientations, which can be studied simultaneously, for example in gas adsorption and reaction studies. 

Since the deviation of device characteristics may come from the local heterogeneity of metal/molecule interfaces, the local characterization of the molecular structure and interfaces is necessary to learn how to alter processes and materials in order to achieve high yield, stable process condition, and low deviations of device characteristics. A few researchers have proposed the use of the scanning probe microscopic technique [conducting probe AFM, surface potential... 

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