Photoemission Characterization of the Oxygen Species During MgO Deposition on GaAs(100) Surface

Synchrotron Radiation Photoelectron Spectroscopy（SRPES） was used to characterize the oxygen species produced during the deposition of ultrathin MgO film on GaAs（100） surface through resistively evaporating metallic Mg in different oxygen atmosphere.It revealed of the results that the form of oxygen species is strongly dependent on the ratio of oxygen and magnesium and under high partial pressure of oxygen very active oxygen intermediates,like O₂^2-,O₂^- etc.,could be easily produced through gas phase reaction of dioxygen with magnesium or adsorption of oxygen molecules over MgO surface.Different oxygen species could be effectively distinguished from each other by photoemission of the electrons on different atomic or molecular orbitals.Based on these results oxide films satisfying different needs,e.g.reactive model catalysts or buffer layers for integrattion of optic-electronic materials,could be prepared.