Structural Transition in Large-Lattice-Mismatch Heteroepitaxy

Abstract

The mechanisms of island nucleation, growth, and dislocation formation in large lattice-mismatch heteroepitaxy are analyzed theoretically. It is shown that 2D platelets tend to transform to 3D islands as they exceed a certain critical size. During island growth, the increase of the strain concentration at the island edge makes it increasingly difficult for adatoms to reach the island, which leads to the formation of homogeneously sized islands. The high strain concentration at the island edge is eventually relieved by growing-in of misfit dislocations.