Book contents
- Frontmatter
- Contents
- Preface
- List of abbreviations
- List of symbols
- 1 Atomic diffusion on surfaces
- 2 Determination of adatom movements
- 3 Atomic events in surface diffusion
- 4 Diffusion on one-dimensional surfaces
- 5 Diffusion on two-dimensional surfaces
- 6 Diffusion in special environments
- 7 Mechanism of cluster diffusion
- 8 Diffusivities of small clusters
- 9 Diffusion of large clusters
- 10 Atomic pair interactions
- Appendix: Preparation of samples for field ion microscopy
- Index
- References
6 - Diffusion in special environments
Published online by Cambridge University Press: 06 July 2010
- Frontmatter
- Contents
- Preface
- List of abbreviations
- List of symbols
- 1 Atomic diffusion on surfaces
- 2 Determination of adatom movements
- 3 Atomic events in surface diffusion
- 4 Diffusion on one-dimensional surfaces
- 5 Diffusion on two-dimensional surfaces
- 6 Diffusion in special environments
- 7 Mechanism of cluster diffusion
- 8 Diffusivities of small clusters
- 9 Diffusion of large clusters
- 10 Atomic pair interactions
- Appendix: Preparation of samples for field ion microscopy
- Index
- References
Summary
Single adatom diffusion on a variety of one- and two-dimensional surfaces has now been surveyed. However, events occurring at plane edges and other types of defects play an important role in affecting diffusion over the entire surface. There are also a huge number of indirect indications that impurities influence atom movement as well as other processes. The amount of direct information available for this field is not large, but we will examine it to gain at least some insight into such phenomena.
Near impurities
Some effort has been made to uncover the way in which atomic diffusion is affected by impurities in the substrate. A start was made by Cowan and Tsong in 1977, who explored the effect of rhenium atoms dissolved in tungsten on the surface diffusion of tungsten atoms on the (110) plane. This surface was prepared from W-3% Re alloy, and so had a number of rhenium substitutional atoms on the (110) plane. Tungsten atoms were then deposited on the surface, and the spatial distribution of places visited by atoms during their thermal movements was measured and compared with that for tungsten moving on the clean W(110), as shown in Fig. 6.1. Tungsten adatoms diffusing over a W-3% Re(110) surface were found to spend more time at a few sites on the surface, which the authors associated as most likely being next to interstitial rhenium atoms embedded in the surface.
- Type
- Chapter
- Information
- Surface DiffusionMetals, Metal Atoms, and Clusters, pp. 423 - 516Publisher: Cambridge University PressPrint publication year: 2010