Real time observation of oxygen chemisorption states on Si(0 0 1)-2×1 during supersonic oxygen molecular beam irradiation

Employing Si 2p and O 1s photoemission spectroscopy using monochromated synchrotron radiation and the supersonic molecular beam technique, we have performed real time in situ observations of oxidation states on Si(0 0 1)-2×1 at room temperature. High-resolution Si 2p photoemission spectra, which unambiguously resolve oxide components [Si1+, Si2+, Si3+ and Si4+], were successfully measured requiring only 43 s per spectrum. We found that the Si4+ species gradually increases to reach the oxide thickness of 0.57 nm just after the saturation of Si1+, Si2+ and Si3+ species with a translational energy of 2.9 eV.