Coadsorption of aluminum and group IV (Si, C) atoms on W(100) surface

Abstract

Electropositive atoms of aluminum adsorbed on a W(100) surface exhibit competition with silicon adatoms for the adsorption sites at high temperatures (1200–1500 K). In this system, silicon displaces aluminum from the tungsten surface. No such competition is observed during the coadsorption of aluminum and carbon, where adatoms of both elements coexist on the tungsten surface (in contrast to the situation previously observed on rhenium, where aluminum atoms displaced carbon to the bulk of substrate). The nature of competition in the systems studied is apparently analogous to that observed previously for Si, C, and S atoms on W(100), despite the fact that aluminum atoms (in contrast to the nonmetals) in the adsorbed state possess a positive charge.