High anisotropy of lateral alignment in multilayered (In,Ga)As∕GaAs(100) quantum dot structures

A formation process for long chains of quantum dots during the molecular-beam epitaxial growth of (In,Ga)As∕GaAs(100) multilayers is presented. The morphology evolution monitored by atomic force microscopy for a series of (In,Ga)As layers demonstrates that the highly anisotropic lateral alignment of dots is gradually developed as the result of the strain field interaction mediated by the GaAs spacer coupled with the anisotropic surface kinetics that occurs during capping the dots. The dot-chain structure, providing unique properties of its own, is demonstrated to serve as a template for the spatially controlled growth of strained quantum dots in general.