Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5360234 | Applied Surface Science | 2010 | 5 Pages |
Abstract
Oxidation of Cu3Au(1Â 1Â 0) using a hyperthermal O2 molecular beam (HOMB) was investigated by X-ray photoemission spectroscopy in conjunction with a synchrotron light source. From the incident energy dependence of the O-uptake curve, the precursor-mediated dissociative adsorption occurs, where the trapped O2 molecule can migrate and dissociate at the lower activation-barrier sites, dominantly at thermal O2 exposures. Dissociative adsorption of O2 on Cu3Au(1Â 1Â 0) is as effective at the thermal O2 exposure as on Cu(1Â 1Â 0). On the other hand, at the incident energies of HOMB where the direct dissociative adsorption is dominant, it was determined that the dissociative adsorption of O2 implies a higher activation barrier and therefore less reactivity due to the Au alloying in comparison with the HOMB oxidation of Cu(1Â 1Â 0). The dissociative adsorption progresses with the Cu segregation on Cu3Au(1Â 1Â 0) similarly as on Cu3Au(1Â 0Â 0). The growth of Cu2O for 2Â eV HOMB suggests that the diffusion of Cu atoms also contribute to the oxidation process through the open face, which makes the difference from Cu3Au(1Â 0Â 0).
Related Topics
Physical Sciences and Engineering
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Authors
Michio Okada, Yuden Teraoka,