The formation, ripening and stability of epitaxially strained island arrays

TL;DR

This paper investigates how epitaxially strained islands form, evolve, and stabilize on mismatched films, revealing effects of surface tension anisotropy, film thickness, and deposition on island morphology and distribution.

Contribution

It provides new insights into the mechanisms of island formation, ripening, and stability in strained epitaxial films, including shape transitions and size distributions.

Findings

Faceted islands form in anisotropic surface tension films.

Island density increases with film thickness.

Bimodal size distribution occurs during shape transition.

Abstract

We study the formation and evolution of coherent islands on lattice mismatched epitaxially strained films. Faceted islands form in films with aniostropic surface tension. Under annealing, these islands ripen until a stable array is formed, with an island density which increases with film thickness. Under deposition, an island shape transition occurs, which leads to a bimodal island size distribution. In films with isotropic surface tension we observe continual ripening of islands above a certain film thickness. A stable wavy morphology is found in thinner films.