ABSTRACT
The defect structure and the critical dimensions for the formation of misfit dislocations in In0.6Ga0.4As islands on GaAs(001) are investigated by high-resolution transmission electron microscopy. By combining dislocation strain field theory with numerical finite element simulations, equations are derived in order to calculate a phase diagram separating the coherent from the incoherent growth regime in dependence on the island size and geometry. It is demonstrated that, if the elastic relaxation of the laterally limited epilayers is taken into account in a quantitative manner, the expressions derived for the coherent-to-incoherent transition are in excellent agreement with the experimental observations.
