THE ADSORPTION OF O2 ON FESI SURFACES

The initial adsorption stages and the interaction of oxygen on FeSi surfaces have been studied as a function of exposure and annealing temperature using a variety of techniques including HREELS, AES, LEED, XPS and UPS. O2 was found to adsorb dissociatively on the FeSi surfaces at room temperature. The whole adsorption process can be divided into four stages. Heating promotes the oxidation of Si, and a thin SiO2 overlayer is formed on the surface when annealed at 450-degrees-C, while all FeOx species are reduced. Models for adsorbed atomic O on the FeSi(100) surface exposed to different oxygen exposures have been put forward to account for the observed experimental results.