Epitaxial Growth of Ag on KCl (100) Surface Observed by LEED and AES

Abstract

A good (1×1) LEED pattern of Ag which is expected from the bulk structure is obtained and Kikuchi pattern is also observed from an epitaxially grown thin Ag film.Primary electrons arriving at the surface through thicker regions of Ag film destroy the KCl surface leaving increased K signals and decreased Cl and Ag signals in AES curve.When AES signals are taken as a function of Ag film thickness, mode of decays of AES signals from Ag, K and Cl shows a usual exponential decay law. However, the film thicknesses which indicate the l/e decrease from the beginning values of Ag, K and Cl Auger signals are very large compared with Auger electron's escape depth, different from each experiment and especially sensitive to an electron bombardment during AES experiment. Their large values are probably due to island growth mechanism of KCl through Ag film.Even if any very thick Ag film is prepared, K and Cl signals are always observed by AES. From this point of view, it is concluded that KCl substrate is dissociated by electron bombardment during AES experiments. Therefore, K escapes to the Ag film surface through channels and Cl is adsorbed on Ag film surface from the gas phase.