Analytic formulations for one-dimensional decay of rectangular homoepitaxial islands during coarsening on anisotropic fcc (110) surfaces
Submonolayer homoepitaxial fcc (110) systems display behavior reflecting strong anisotropy at lower temperatures, including one-dimensional decay during Ostwald ripening of rectangular islands maintaining constant width in the (001) direction. To appropriately describe this behavior, we first develop a refined continuum Burton-Cabrera-Frank formalism, which accounts for a lack of equilibration of island shape and importantly also for inhibited incorporation of adatoms at almost-faceted (1¯10) island edges through effective kinetic coefficients. This formalism is shown to describe accurately the adatom diffusion fluxes between islands and thus island evolution for a complex experimental island configuration, as confirmed by matching results from realistic atomistic simulations for this configuration. This approach also elucidates basic dependencies of flux on island geometry and temperature. Second, a further refinement is presented incorporating separate terrace and edge adatom density fields either in a continuum setting or alternatively in a spatially discrete diffusion equation setting. The second approach allows more flexibility and accuracy in accounting for edge-diffusion kinetics including corner rounding, a lack of equilibration of the edge adatom density at (1¯10) island edges, and the effect of rare kinks on (1¯10) island edges. Finally and significantly, it suggests facile two-way corner rounding at the island periphery during island decay, contrasting the previous picture.
- Research Organization:
- Ames Lab., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-07CH11358
- OSTI ID:
- 1132063
- Report Number(s):
- IS-J 8183; PRBMDO
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 88, Issue 15; ISSN 1098-0121
- Publisher:
- American Physical Society (APS)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Understanding the effects of strain on morphological instabilities of a nanoscale island during heteroepitaxial growth
Modeling of Diffusivity for 2D Vacancy Nanopits and Comparison with 2D Adatom Nanoislands on Metal(100) Surfaces Including Analysis for Ag(100)