Local probe

Central to all SPMs (or local probe methods , or local proximal probes as they are sometimes called) is the presence of a tip or sensor, typically of less than 100 mn radius, that is rastered in close proximity to—or in contact with—tire sample s surface. This set-up enables a particular physical property to be measured and imaged over the scaimed area. Crucial to the development of this family of teclmiques were both the ready availability of piezoelements, with which the probe can be rastered with subnanometre precision, and the highly developed computers and stable electronics of the 1980s, without which the operation of SPMs as we know them would not have been possible. 

SECM is a scaiming-probe teclmiqiie introduced by Bard et aJ in 1989 [49, and M ] based on previous studies by the same group on in situ STM [ ] and simultaneous work by Engstrom et aJ [53 and M], who were the first to show that an amperometric microelectrode could be used as a local probe to map the concentration profile of a larger active electrode. SECM may be envisaged as a chemical microscope based on faradic current changes as a microelectrode is moved across a surface of a sample. It has proved iisefiil for... 

One of the most important advances in electrochemistry in the last decade was tlie application of STM and AFM to structural problems at the electrified solid/liquid interface [108. 109]. Sonnenfield and Hansma [110] were the first to use STM to study a surface innnersed in a liquid, thus extending STM beyond the gas/solid interfaces without a significant loss in resolution. In situ local-probe investigations at solid/liquid interfaces can be perfomied under electrochemical conditions if both phases are electronic and ionic conducting and this... 

The most recent approach to reductive nanofabrication that can indeed constmct nanoscale stmctures and devices uses microscopic tools (local probes) that can build the stmctures atom by atom, or molecule by molecule. Optical methods using laser cooling (optical molasses) are also being developed to manipulate nanoscale stmctures. 

Schlapka A, Kasberger U, Menzel D, Jakob P. 2002. Vibrational spectroscopy of CO used as a local probe to study the surface morphology of Pt on Ru(0001) in the submonolayer regime. Surf Sci 502/503 129. 

Stimming U, Vogel R. 1998. In-situ local probe techniques at electrochemical interfaces. In Lorenz WJ, Plieth W, eds. Electrochemical Nanotechnology. Weinheim Wiley-VCH. 

Scanning Electrochemical Microscopy as a Local Probe of Chemical Processes at Liquid Interfaces... 

Measurement based on heat flux effects This approach uses local probing devices such as hot-wire anemometers and microthermocouples. The hot-wire anemometer can be either a constant-temperature system or a constant-heat-flux system. Because of the difference in heat transfer between the exposed fluid (liquid or gas)... 

Jaber, M., M-Brendle, J., Delmotte, L. and Le Dred, R. (2003) New range of Al-Mg organoclays with tailored hydrophobicity incorporation of fluoride as a local probe to study... 

Gimzewski JK, Joachim C (1999) Nanoscale science of single molecule using local probes. Science 283 1683... 

In-Situ Local Probe Techniques for Studies of Electrochemical Interfaces (W. J. Lorenz and W. Plieth, eds.), VCH-Wiley, New York, 1998. Proceedings of the lUVSTA Workshop on Surface Science and Electrochemistry, Surf. Sci. 555 (1995). 

Tomoda, M., Shiraishi, N., Kolosov, O. V., and Wright, O. B. (2003). Local probing of thermal properties at submicron depths with megahertz photothermal vibrations. Appl. Phys. Lett. 82, 622-4. [318]... 

Figure 2.1. Schematic picture illustrating the local probe character in XES for N2 adsorbed on a Ni surface. From the total charge density (gray envelope) valence electrons with p-angular momentum (contour lines) decay into the N Is core hole. From Ref. [3].

Inspired by these Surface Science studies at the gas-solid interface, the field of electrochemical Surface Science ( Surface Electrochemistry ) has developed similar conceptual and experimental approaches to characterize electrochemical surface processes on the molecular level. Single-crystal electrode surfaces inside liquid electrolytes provide electrochemical interfaces of well-controlled structure and composition [2-9]. In addition, novel in situ surface characterization techniques, such as optical spectroscopies, X-ray scattering, and local probe imaging techniques, have become available and helped to understand electrochemical interfaces at the atomic or molecular level [10-18]. Today, Surface electrochemistry represents an important field of research that has recognized the study of chemical bonding at electrochemical interfaces as the basis for an understanding of structure-reactivity relationships and mechanistic reaction pathways. 

Figure 12-9 shows in-situ measurements with local probes for the Ag chemical potential of Ag2+ S during the a->0 transformation induced by undercooling. In... 

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