| Abstract
| - X-ray photoelectron spectroscopy (XPS) and atomic force microscopy have been used to study Co nanoparticlesevaporated onto freshly cleaved highly oriented pyrolytic graphite (HOPG) surfaces. XPS chemicalcharacterization employed symmetrical line shapes and was carried out as functions of the amount of Codeposited and of the time subsequent to deposition. The nominal amounts of evaporated Co ranged from 0.5to 175 Å. On analyzing the relationships among the Co2p, C1s, and O1s spectra, we found that evaporatedCo reacts not only with HOPG surface defects (including oxidized carbon contaminant groups), but also withresidual C- and O-containing species present in the vacuum chamber. Both carbide and oxide are producedas surface layers around each nanoparticle, stabilizing them and preventing further coalescence.
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