| Summary: | 碩士 === 國立中正大學 === 物理所 === 97 === We have deposited cobalt atoms on the highly oriented pyrolytic graphite (HOPG) at room temperature. By using atomic force microscopy (AFM) to observe the morphology of the Co deposited HOPG surface, we have studied the Co growth mode. Co atoms form two kinds of islands on the HOPG surface: one along steps and the other on terraces. Our attention has been concentrated on islands grown on terraces.
By measuring the diameter of terrace islands and fitting the diameter distribution to a functional form derived from the scaling theory for a range of Co deposition conditions, we have found the critical island size of the Co islands to be 6 Co atoms. The deposition conditions include different Co atom fluxes and lengths of deposition time.
We have also obtained nice fittings of the distributions of islands’ nearest neighbor distance and diameter to the capture zone theory, enforcing the conclusion derived from the scaling theory that, at room temperature, the critical island size of the Co islands is the same for various growth conditions. Furthermore, the capture zone model expects no island coalescence or ripening occurs under the discussed growth conditions.
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