Abstract
We have studied the morphology of a bulk-crystalline metal, Ag, deposited on a clean surface of a metallic glass, Zr-Ni-Cu-Al. At 190-300 K, the films exhibit Stranski-Krastanov-like growth, wherein three-dimensional clusters form atop an Ag wetting layer that is 4-5 monolayers thick. Above this coverage, cluster growth competes with growth of the flatter regions. The cluster density increases with decreasing temperature, indicating that the conditions of island nucleation are far-from-equilibrium. Within a simple model where clusters nucleate whenever two mobile Ag adatoms meet, the temperature-dependence of cluster density yields an (reasonable) upper limit for the value of the Ag diffusion barrier on top of the Ag wetting layer of 0.32 eV. Overall, this prototypical study suggests that it is possible to grow films of a bulk-crystalline metal that adopts the amorphous character of a glassy metal substrate, if film thickness is sufficiently low.
| Original language | English |
|---|---|
| Pages (from-to) | 6486-6492 |
| Number of pages | 7 |
| Journal | Thin Solid Films |
| Volume | 517 |
| Issue number | 24 |
| DOIs | |
| State | Published - Oct 30 2009 |
| Externally published | Yes |
Funding
The experimental component of this work was supported by the Office of Science, Basic Energy Sciences, Materials Science Division of the U.S. Department of Energy (USDOE) through the Ames Laboratory. Ames Laboratory is operated by Iowa State University of Science and Technology under Contract No. DE-AC02-07CH11358. The theoretical analysis (JWE) was supported by NSF grant CHE-0809472. We thank J. W. Anderegg for the Auger analysis.
| Funders | Funder number |
|---|---|
| Materials Science Division | |
| University of Science and Technology | |
| National Science Foundation | CHE-0809472, 0809472 |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | |
| Ames Laboratory |
Keywords
- Film structure
- Growth mode
- Metallic glass
- Scanning tunneling microscopy
- Silver