Synchrotron radiation photoelectron spectroscopy study on oxide evolution during oxidation of a Si(111)-77 surface at 300 K; Comparison of thermal equilibrium gas and supersonic molecular beams for oxygen adsorption

Yoshigoe, Akitaka ; Teraoka, Yuden

Translational energy of gas molecules is a fundamental physical quantity in gas-solid reactions. Understanding adsorption process of thermal gas in terms of translational energy remains an unsolved issue. Here, for thermal-O and supersonic O molecular beams, we present a comparative study of oxide evolution at a Si(111)-77 surface at room temperature. Real-time observations of oxides were conducted by employing synchrotron radiation photoelectron spectroscopy. It was found that ins structure is the common first product for oxidation by thermal-O and supersonic O molecular beams. Similarities between them for oxide evolution were found and illustrate the notion that translational energy of thermal O can be ascribed to the average molecular kinetic energy defined based on the most probable speed of the Maxwell-Boltzmann distribution. This experimental result suggests that translational energy is the unifying reaction parameter that rationalizes adsorption mechanisms.