Analytic formulations for one-dimensional decay of rectangular homoepitaxial islands during coarsening on anisotropic fcc (110) surfaces

TitleAnalytic formulations for one-dimensional decay of rectangular homoepitaxial islands during coarsening on anisotropic fcc (110) surfaces
Publication TypeJournal Article
Year of Publication2013
AuthorsWang CJ, Han Y, Walen H, Russell SM, Thiel PA, Evans JW
Journal TitlePhysical Review B
Volume88
Pages155434
Date Published10
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000326092900002
Keywordsag(110), epitaxial-growth, kinetic-model, metal-surfaces, monte-carlo, NANOSTRUCTURES, STEP, transition
Abstract

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) over bar 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) over bar 10 > island edges, and the effect of rare kinks on <(1) over bar 10 > island edges. Significantly, it suggests facile two-way corner rounding at the island periphery during island decay, contrasting the previous picture.

URL<Go to ISI>://WOS:000326092900002
DOI10.1103/PhysRevB.88.155434