Effects of coupling on the structural properties of InxGa1-xAs/GaAs 1-D and 0-D sell-organized quantum structures

Self-organized, vertically stacked 1-D (quantum wires) and 0-D (quantum dot s) low-dimensional materials can exhibit different optical and structural p roperties by virtue of the different strength of coupling, which is related to the thickness of the barrier layers. In this work these properties have been investigated for InxGa1-xAs/GaAs self-organized quantum structures us ing photoluminescence spectroscopy and transmission electron microscopy. In the case of the wires, the reduced thickness of the barrier does not influ ence the structural properties but just splits the uncoupled levels into sy mmetric and antisymmetric levels. In the case of the quantum dots, a critic al change of the structural properties has been observed; in particular, a transition of the InxGa1-xAs quantum well from fully developed and defect f ree quantum dots to completely incoherent islands has been found as a conse quence of the reduction of the barrier layer thickness. (C) 2001 Elsevier S cience B.V. All rights reserved.