Three-dimensional analysis of shape transitions in strained-heteroepitaxial islands.

A continuum model of shape transitions in strained heteroepitaxial islands predicts that small islands are hut shaped, while larger islands are domed. The volume of a stable hut can exceed that of a stable dome, however, indicating that the stability of hut-shaped islands plays an important role in shape transition, in addition to energy changes associated with the transition. A hut-shaped island loses stability upon reaching a critical volume, which depends on the anisotropy in surface energy. Impingement between islands reduces the critical volume by nucleating new facets at the base of a hut, which subsequently trigger a shape transition. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]