Local-electrode atom-probe

Schematic of local electrode atom probe with delay line detector. ... 

D.R. Strait, First data from a commercial local electrode atom probe (LEAP) , Microsc. Microanal, 2004,10, 373-383. 

FIGURE 40.29 Comparison of depth profiles of As as measured by 3D local electrode atom probe (3D LEAP) and secondary ion mass spectrometry (SIMS). Reprinted with permission from Thompson, K., Booske, J.H., Larson, D.J., Kelly, T.F. (2005) Applied Physics Letters 87, p. 052108. Copyright 2005, American Institute of Physics. 

Miller, M.K., Russell, K.F. (2007) Performance of a local electrode atom probe. Surface and Interface Analysis, 39, 262-267. 

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. 

The usual objective of scanning probe microscopy techniques [41] is to provide images of a solid surface—normally topographic information— with up to atomic resolution. However, they can also be used to probe local solution composition and electrode reactions, as will be described. 

The discussed models have been developed for liquid electrodes, as mentioned previously. On solid surfaces, due to the presence of atomic steps and crystal defects different atomic sites exist which differ in energy. Specific adsorption then is expected to occur preferentially at certain sites rather than uniformly. Site specific adsorption phenomena can in principle be studied with local probe methods such as the STM, but their discussion is beyond the scope of this book. 

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