Ostwald ripening of cobalt silicide islands on Si(111)-5×2/Au
| Autor: | WEN-YI HSU, 徐穩壹 |
|---|---|
| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 We have studied the growth of cobalt silicide islands by heating Co-deposited Si(111)-(5×2)/Au surfaces with scanning tunneling microscopy. In the first part of our study, we have deposited 0.6 ML of Co on a Si(111)-(5?2)/Au surface at room temperature (RT) followed by 610?C heating. Upon heating cobalt silicide islands formed randomly both on terrace and at step edges. With further heating islands at step edges grow at the expense of those on terraces, most of which dissolve completely at large time. The second part of the study involves an initial deposition of 0.3 ML of Co at RT followed by 680?C heating. By doing so most of the islands are large and concentrate at step edges. We then deposited additional 0.6 ML of Co at RT followed by 610?C heating. The change in island density and size are monitored as a function of heating time. Power-law dependences of the island density and radius on the growth time have been found to be proportional to t -0.568 and t -0.198, respectively. Both exponents agree nicely with a model of one-dimensional (1-D) Ostwald ripening process. This favorable comparison leads us to conclude that our experiment has demonstrated a unique island ripening process with the rate-limiting process being the diffusing species confined to travel along surface steps, mimicking a 1-D ripening process. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|