Excited electronic state on Si(0 0 1) surface at initial stage of oxidation studied by two-photon photoemission spectroscopy
| Autor: | Yusuke Kurahashi, Kazutoshi Takahashi, Junpei Azuma, Takeshi Koga, Masao Kamada |
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| Rok vydání: | 2011 |
| Předmět: |
Radiation
Valence (chemistry) Photoemission spectroscopy Scattering Chemistry Inverse photoemission spectroscopy Oxide Angle-resolved photoemission spectroscopy Electron Condensed Matter Physics Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials chemistry.chemical_compound Physical and Theoretical Chemistry Atomic physics Spectroscopy |
| Zdroj: | Journal of Electron Spectroscopy and Related Phenomena. 184:304-308 |
| ISSN: | 0368-2048 |
| DOI: | 10.1016/j.elspec.2011.03.005 |
| Popis: | The excited electronic states on Si(0 0 1) surface at the initial stage of oxidation have been studied by time-resolved two-photon photoemission (2PPE) spectroscopy. Transient 2PPE intensity from the conduction band minimum (CBM) shows the maximum at about 1 ps after a direct excitation from bulk valence- to conduction-band. This is due to accumulation of photo-excited electrons to CBM by the intraband scattering. The 2PPE signal around 0.6 eV below CBM shows a maximum intensity at around 10 ps. It can be considered that this 2PPE intensity originates from the unoccupied state derived from surface oxide. Electrons at both CBM and oxide state show longer lifetimes as oxidation proceeds. |
| Databáze: | OpenAIRE |
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