In-line correlation and ordering of InAs/GaAs multistacked Quantum Dots structures

• In Quantum Dot multilayers, we have measured an increasing correlation of the Quantum Dot in-line distances.
• The increase of the in-line Quantum Dot ordering is driven mainly by the propagation of the elastic strain field through the layers.
• Finite Element Method simulations confirm a tendency towards in-line ordering as function of the increasing number of layers.
• The elongated step bunchings are responsible for an improvement of the alignment properties of Quantum Dot chains.

Several multilayer InAs/GaAs(001) samples were grown in a Molecular Beam Epitaxy chamber under critical growth conditions in order to induce the self-assembling of chains of InAs Quantum Dots over mounded GaAs surfaces. As the number of deposited layers was increased, an increasing in-line ordering was observed. Finite Element Method simulations confirmed this trend which is driven mainly by the propagation of the elastic strain field through the layers. On the other hand, the morphological features of the surface contribute to improving the alignment of the InAs Quantum Dots in every chain.