Tool insulation insulating solution

The measurement of changes of the surface potential Vo at the interface between an insulator and a solution is made possible by incorporating a thin film of that insulator in an electrolyte/insulator/silicon (EIS) structure. The surface potential of the silicon can be determined either by measuring the capacitance of the structure, or by fabricating a field effect transistor to measure the lateral current flow. In the latter case, the device is called an ion-sensitive field effect transistor (ISFET). Figure 1 shows a schematic representation of an ISFET structure. The first authors to suggest the application of ISFETs or EIS capacitors as a measurement tool to determine the surface potential of insulators were Schenck (15) and Cichos and Geidel (16). 

Some of the theoretical tools laid in Chapter 3 are fully exploited in Chapter 4, which exposes the reader to the actual problems (and proposed solutions) of the chemistry and physics of modern and technologically relevant polyconjugated polymers in their intact (insulating) and in the doped (electrically conducting) states. 

First, STM images in liquids were obtained in electrically insulating fluids such as N2 or paraflin oil [67]. However, it was demonstrated in 1986 that STM measurements can also be operated in conducting hquids such as a saline solution [68]. Consequently, STM at solid/Hquid interfaces has become an important tool for studying electrochemical processes in situ [72-78], and it is also of help in fields such as catalysis, corrosion, lubrication, and biological research [79]. 

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