The structure transition from vertical alignment to anti-alignment of InAs/InP quantum dot multilayers

We calculate the minimum Gibbs free energy of the InAs/InP quantum dot multilayer by combining the method of moving asymptotes and the finite element method. Based on the principle of the least energy, the transition between vertically aligned and anti-aligned quantum dot multilayers is studied. We investigate the influence of quantum dot base size and density on critical spacer thickness for the transition. The study results indicate that the critical thickness increases with the decrease in the density of quantum dots, while the base size of the quantum dot is linear to the critical thickness when the density is given.

► The transition between vertically aligned and anti-aligned quantum dot multilayers is studied by minimal energy principle.
► The anti-aligned structure is favorable for nucleation with the thin spacer when QDs possess high densities.
► The coupling strain field of the buried QDs is the main force to create those transitions.