CHARACTERIZATION OF THE SURFACE-STRUCTURE OF SILVER SINGLE-CRYSTAL ELECTRODES BY EXSITU AND INSITU STM

The surface characterstics of "real" and "quasi-perfect" silver single-crystal electrodes were studied by ex situ and in situ STM under atmospheric conditions and in electrolyte solutions, respectively. In both cases, atomically resolved STM images were obtained showing different surface structures. The atomic structures observed by in situ STM studies correspond exactly to the surface structures of Ag(100) and Ag(111) single-crystal faces. The ex situ STM studies revealed different structures of the topmost monatomic layer, which can be attributed to a surface modification by oxygen from the ambient atmosphere. Spectroscopic data for the tunneling current as well as Auger and XPS measurements are in agreement with this assumption. It is found that the surface characteristics of silver single-crystal electrodes depend strongly on the preparation procedure and on the time of exposure in air.