Strain-engineered arrays of InAs quantum dots on GaAs(001): Epitaxial growth and modeling

Working under critical conditions for dot nucleation in a Molecular Beam Epitaxy chamber, we were able to drive the formation of InAs dot chains to precise locations in multilayered samples grown on a rippled GaAs(001) surface. We discussed the role of the elastic field and the surface curvature in determining the dot arrangement at each stacked layer, proving a new mechanism of self-organization of the dots. In particular, we succeeded in controlling the interplay between elastic and curvature effects and we showed how a selection process is achievable in the chain formation. The role of the stress field was also studied by means of Finite Element Method simulations, and we gained a valuable understanding of the interlayer dot correlations for dot arrays with variable cap thicknesses. We proved the existence of an anisotropy in the cap formation of isolated dots, which appeared to be directly related to our peculiar growth geometry and experimental set-up.