Electron-stimulated processes at solid surfaces

Abstract

Surface analytic techniques that use incident electrons as the initial stimuli have, in many cases, been shown to be destructive. Examples of such destructive processes include the decomposition of chemisorbed species, stimulated surface reactions with gas-phase components, and the desorption of chemisorbed atoms. Since such processes reflect chemical changes in the surface under investigation, studies of these processes can yield useful surface information. In a review of some electron-stimulated surface reactions, the types of surface-chemistry information to be expected is discussed. Recent results of an electron-stimulated-desorption (ESD) investigation of the interaction of oxygen with Ni, W, and Mo surfaces are presented. Measurements of threshold values and of the energy distribution of ions desorbed for excitation energies near and well above threshold were made using potential-modulation techniques. A comparison is presented between these ESD results and soft-x-ray appearance potential measurements made on the same chemisorptive systems.