Morphological transitions during Si capping in Ge/Si nanoislands

Atomistic modelling is carried out which supports a continuum model we have developed to explain the recently observed shrinkage of GeSi/ Si(001) quantum dots during Si capping. It is shown that Si diffusion into the subsurface layers of the quantum dot significantly lowers the total strain energy of the quantum dot. Taking into account interdiffusion between the quantum dots and the wetting layer, it is further shown that the continuum model predicts an earlier transformation from domes to pyramids and a significantly reduced final size of the capped island than if only intermixing with Si deposited on the island were taken into account. Copyright © 2008 American Scientific Publishers. All rights reserved.