The study of solid surfaces by electrochemical methods

The basic concepts of electrochemistry at the solid-electrolyte interface are discussed in this article with special emphasis on surface physical aspects. The electrochemical environment is shown to provide several unique experimental possibilities for the study of metal and semiconductor surfaces. Chemisorption processes, which are associated with charge transfer across the interface, can be studied with great accuracy, even when only submonolayer amounts are adsorbed. Semiconductor electrodes have recently received increasing attention and their fundamental properties, as well as selected experimental results, are described here. The optical reflectance of metal electrodes measures sensitively overlayers and the electric charge on the surface, both of which can easily be controlled by the voltage applied to the electrochemical cell. The final topic is photo-emission, which is usually associated with ultra high vacuum conditions but which, when studied at a metal-electrolyte contact, can be used to obtain complementary information, particularly at low excitation energies.