Auger and photoelectron study of codeposited sulfur and oxygen layers on silver (111)

Abstract

When oxygen and sulfur are codeposited on a silver surface, the sulfur L2,3MM Auger spectrum is altered significantly from that obtained when sulfur alone is deposited. Besides a chemical shift due to the observed 6.6-eV sulfur L2,3 binding energy increase on coadsorption with oxygen, the oxygen L1 core level and a hybridized sulfur level in the valence band participate in the sulfur Auger process, introducing new Auger peaks similar to those present in surfaces containing SO4= groups. Electron bombardment of this film preferentially desorbs oxygen and alters the Auger spectrum back to one characteristic of films of sulfur alone on silver. These Auger spectra are analyzed on the basis of a model which uses experimentally determined initial states and small final-state effects.