Analysis of strained island energetics in Ge/Si(001) growth

The numerical calculation for Ge/Si(001) heteroepitaxial growth is performed. We adopt the most widely used Stillinger-Weber potential, and the island energies of the three types, two-dimensional island, pyramid and dome, are explored as a function of the lateral size. These island energies are compared with each other to find the island morphology which has the lowest energy. Then, a growth history of the most stable growth mode is searched. Although the result reproduces qualitatively the Stranski-Krastanov growth as observed in the experiments, quantitative differences between our result and experiments in the critical wet layer thickness and the island morphology are found.