The morphological stability of coherent thin films subjected to unequal in-plane biaxial strains was investigated to determine how non-uniform strain states could be used to influence the growth of self-organized island nano-structures. The evolution via surface diffusion was modelled analytically using a small perturbation approach and allows for anisotropies in the surface energy and the surface diffusivity. It was shown that conventional uniform biaxial epitaxy did not provide a driving force towards a particular wavelength as was popularly assumed. This reduced the potential for highly self-organized growth. It was predicted that improvements in island size, shape and spatial

distributions could be obtained under certain conditions of anisotropic strain, surface energy and surface diffusivity. This increase in uniformity would be beneficial to the construction of practical devices. Enhancing surface diffusivity anisotropy via the application of an applied strain could offer the most realistic opportunity for controlling the growth of self-assembled structures this way.

Self-Organized Growth on Strained Substrates - the Influence of Anisotropic Strain, Surface Energy and Surface Diffusivity. S.P.A.Gill: Thin Solid Films, 2003, 423[2], 136-45