synchrotron radiation photoelectron spectroscopy study of the oxidation of the Ge(100)-21 surface by supersonic molecular oxygen beams

超音速酸素分子線によるGe(100)-21表面酸化に関するその場放射光光電子分光研究

吉越 章隆 ; 寺岡 有殿; 岡田 隆太; 山田 洋一*; 佐々木 正洋*

Yoshigoe, Akitaka; Teraoka, Yuden; Okada, Ryuta; Yamada, Yoichi*; Sasaki, Masahiro*

酸素分子の並進エネルギーを2.2eVまで変えた時のGe(100)21表面の飽和酸化まで表面状態をその場放射光光電子で調べた。飽和吸着酸素量が1モノレイヤー以下であり、Si表面酸化と大きく異なり酸化数が+2までであることが分かった。直接活性化吸着によるGe成分の増加を伴う吸着量の促進を観測した。本研究は室温における酸素吸着プロセスの基礎的理解に貢献する。

synchrotron radiation photoelectron spectroscopy was performed during the oxidation of the Ge(100)-21 surface induced by a molecular oxygen beam with various incident energies up to 2.2 eV from the initial to saturation coverage of surface oxides. The saturation coverage of oxygen on the clean Ge(100) surface was much lower than one monolayer and the oxidation state of Ge was +2 at most. This indicates that the Ge(100) surface is in strong contrast to Si surfaces. The direct adsorption process can be activated by increasing the translational energy, resulting in an increased population of Ge and a higher final oxygen coverage. Our findings will contribute to the fundamental understanding of oxygen adsorption processes at 300 K from the initial stages to saturated oxidation.