CHCl dissociation, CH abstraction, and Cl adsorption from the dissociative scattering of supersonic CHCl on Cu(111) and Cu(410)

Makino, Takamasa*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Dio, W. A.*; Okada, Michio*

Applied Surface Science, 642, p.158568_1 - 158568_6, 2024/01

https://doi.org/10.1016/j.apsusc.2023.158568

Revisit of XPS studies of supersonic O molecular adsorption on Cu(111); Copper oxides

Hayashida, Koki*; Tsuda, Yasutaka; Yamada, Takashi*; Yoshigoe, Akitaka; Okada, Michio*

ACS Omega (Internet), 6(40), p.26814 - 26820, 2021/10

https://doi.org/10.1021/acsomega.1c04663

We report the X-ray photoemission spectroscopy (XPS) characterization of the bulk CuO(111) surface and 8-type and 29-type oxide structures on Cu(111) prepared by using 0.5 eV O supersonic molecular beam (SSMB) source. We propose a new structural model for the 8-type oxide structure and also confirmed the previously proposed model for the [29] oxide structure on Cu(111), based on the O1s XPS spectra. The detection-angle dependence of the O 1s spectra supports that the nanopyramidal model is more preferable for the (X)R30 CuO(111). We also report the electronic excitations which O1s electrons suffer.

Oxidation processes of copper-gold alloy surface induced by supersonic oxygen molecular beam

Okada, Michio*; Tsuda, Yasutaka*; Yoshigoe, Akitaka; Dio, W. A.*

Do To Dogokin, 56(1), p.232 - 236, 2017/00

We reported the our studies on the surface temperature (Ts) dependence of oxidation on the CuAu(111) surface by a supersonic O molecular beam, using synchrotron radiation X-ray photoemission spectroscopy. Clean surface shows strong Au segregation to the top layer, i.e., Au surface enrichment of the clean surface. Complete Cu segregation to the surface occurs at 0.5 ML O surface coverage. The Au-rich second and third layers of the oxidized surface demonstrate the protective layer formation against oxidation deeper into the bulk. We found that CuO formation occurs. At Ts = 300K, the CuO growth is not so effective. The surface oxidation is less effective on CuAu(111) than on Cu(111). At Ts = 400K, the protection by the Au-rich layer against oxidation into bulk is effective. At Ts = 500K, the Au protective layer is broken due to effective Au diffusion and thus CuO grows deeper into bulk.

Surface temperature dependence of oxidation of CuAu(111) by an energetic oxygen molecule

Tsuda, Yasutaka*; Yoshigoe, Akitaka; Teraoka, Yuden; Okada, Michio*

Materials Research Express (Internet), 3(3), p.035014_1 - 035014_8, 2016/03

https://doi.org/10.1088/2053-1591/3/3/035014

We report a study on the surface-temperature () dependence of oxidation process at CuAu(111) by using a hyperthermal oxygen molecular beam and synchrotron-radiation X-ray photoemission spectroscopy. The O-1s spectra and the corresponding O-uptake curves demonstrate that CuO domains grow effectively at high of 400 and 500 K. The simple analysis of the O distribution suggests that the temperature-induced atomic diffusion causes the CuO domains growing thicker at 500 K. The oxidation of CuAu(111) is less efficient at = 300-500 K than that of Cu(111), demonstrating that the protective nature of CuAu against oxidation, in comparison to Cu, remains even at high .

Initial stages of CuAu(111) oxidation; Oxygen induced Cu segregation and the protective Au layer profile

Tsuda, Yasutaka*; Oka, Kohei*; Makino, Takamasa*; Okada, Michio*; Dio, W. A.*; Hashinokuchi, Michihiro*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Hideaki*

Physical Chemistry Chemical Physics, 16(8), p.3815 - 3822, 2014/02

https://doi.org/10.1039/c3cp54709d

Oxidation of TiAl surface with hyperthermal oxygen molecular beams

Hashinokuchi, Michihiro*; Tode, Mayumi*; Yoshigoe, Akitaka; Teraoka, Yuden; Okada, Michio*

Applied Surface Science, 276, p.276 - 283, 2013/07

https://doi.org/10.1016/j.apsusc.2013.03.082

The Effect of step geometry in copper oxidation by hyperthermal O molecular beam; Cu(511) vs Cu(410)

Okada, Michio*; Vattuone, L.*; Rocca, M.*; Teraoka, Yuden

Journal of Chemical Physics, 136(9), p.094704_1 - 094704_8, 2012/03

https://doi.org/10.1063/1.3690019

Synchrotron X-ray photoemission study of NiTi surface oxidation with hyperthermal oxygen molecular beam

Yamazaki, Daichi*; Sowa, Makoto*; Okada, Michio*; Teraoka, Yuden; Kasai, Toshio*

Journal of the Vacuum Society of Japan, 54(5), p.307 - 312, 2011/05

https://doi.org/10.3131/jvsj2.54.307

The Study of oxidation on TiAl surface with photoemission spectroscopy in conjunction with synchrotron radiation

Hashinokuchi, Michihiro*; Sumimoto, Yuichi*; Tode, Mayumi; Harries, J.; Okada, Michio*; Teraoka, Yuden; Kasai, Toshio*

Denki Gakkai Rombunshi, C, 130(10), p.1723 - 1729, 2010/10

https://doi.org/10.1541/ieejeiss.130.1723

The oxidation processes on a TiAl surface induced by a hyperthermal O molecular beam (HOMB) with a translational energy of 2.2 eV was studied by X-ray photoemission spectroscopy in conjunction with synchrotron radiation. At a surface temperature of 300 K, the simultaneous growth of Al and Ti oxides accompanied with the segregation of AlO near the surface was observed. The efficiency of oxidation for the HOMB incidence was smaller than that for O backfilling (25 meV). Furthermore, the chemical compositions of oxide species (AlO, TiO, TiO) on the TiAl surface were independent of the translational energy of incident O molecule. The present results suggest that the oxidation on TiAl surface proceeds via precursor molecular states.

Fabrication of Cu oxides on single crystal Cu surfaces using hyperthermal O molecular beams

Okada, Michio*; Moritani, Kosuke*; Vattuone, L.*; Savio, L.*; Teraoka, Yuden; Kasai, Toshio*; Rocca, M.*

Metal Oxide Nanostructures and Their Applications, 1, p.205 - 237, 2010/03

The use of hyperthermal O molecular beams may improve the quality of thin film growth, for example, for organic films, and allow the production of oxide layers at lower crystal temperatures, avoiding contamination problems and reducing film defects. Collision-induced absorption and local heating of the substrate were shown to be indeed effective in inducing oxide nucleation, opening up new possibilities for the production of nanostructured metal oxides. Herein we offer an overview on recent detailed studies of oxygen adsorption and of the initial stages of CuO and CuO formation on low Miller index and vicinal Cu surfaces. We introduce the hyperthermal molecular beam technique and give some details on the experimental apparatuses. We discuss the available data for Cu(100), Cu(410) and Cu(110) and Cu(111), respectively.