Reconstruction of platinum－study of faceting and missing-row
| Autor: | Rung-Jiun Lin, 林榮君 |
|---|---|
| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 Faceting and missing-row of Pt surface reconstruction are observed by field ion microscopy (FIM). In order to reducing the surface energy, it may facet and forms the missing-row on the surface. In the point of view for faceting, while anneal temperature increases, those low-surface-free-energy surfaces including (111)、(100)、(110)、(311) extend. As the temperature is arising to 700K, the (310) surface starts to extend. This implies that even though the surface free energy is low enough, the surface still cannot facet if the applied energy is lower than the dynamic energy of surface atoms. In the point of view for missing-row, surface structures reconstruct from (1×1) to missing-row (1×2) on (110), (311), (331) and (211) surfaces. (331) and (211) surfaces have two mono-layer (1×2) reconstructions. This structure can be attributed to adding-atom, missing-atom, or atom-jumping. This behavior corresponds to faceting simultaneously. The surface borders of different index keep connected after surface reconstruction. Besides, (113) surface reconstructs again from (1×2) to (2×2) at 650K. In addition, Pt80Ir20 alloy are also observed in this study. The observation shows that the bond in this alloy is strong, and there are superlattice structures on (100) facets. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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