Physics and chemistry during the deposition and oxidation of ultrathin Mg overlayer on GaAs(1Â 0Â 0) surface

The interaction of active Mg metal with GaAs(1 0 0) surface as well as the oxidation of Mg ultrathin film were studied employing synchrotron radiation photoemission (SRPES) technique. Interfacial reaction was obviously observed through the energy shifts of Mg2p, Ga3d and As3d levels. The resulted Mg ultrathin film was easily and completely oxidized on exposure of oxygen indicating its polycrystalline nature and high sensitivity to oxygen. A model of Mg/GaAs(1 0 0) interface is proposed and the physical and chemical phenomena during the deposition and oxidation of Mg ultrathin film were discussed.