Role of steps in CuO formation on Cu(410) using a hyperthermal O molecular beam

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

Herein we report the results of our detailed studies on the initial oxidation process, especially the CuO formation, on Cu(410). From the high-resolution electron energy-loss spectroscopy (HREELS), the CuO formation is verified at a high temperature for the thermal O exposure. However, from the X-ray photoemission spectroscopy (XPS) measurements in conjunction with synchrotron radiation (SR), the efficiency of CuO formation is quite low for the thermal O exposure. On the other hand, it was found on Cu(410) that hyperthermal O molecular beams (HOMB) at 2.2eV is an efficient tool for the fabrication of CuO even at room temperature or at lower temperatures. The O-1s and valence-band XPS spectra clearly demonstrate the characteristic features of CuO formation induced by HOMB. Furthermore, such CuO formation depends strongly on the azimuthal direction of the incident HOMB, impinging dominantly on a terrace or on a step.