Spontaneous lateral alignment of multistacked In0.45Ga0.55As quantum dots on GaAs(3 1 1)B substrate

In0.45Ga0.55As/GaAs multistacking quantum dot (QD) structures were fabricat ed on a GaAs(3 1 1)B substrate by metalorganic vapor-phase epitaxy. QDs spo ntaneously aligned in the [0 1 1] direction were observed on stacked QDs, w hereas QDs were randomly distributed at the first In0.45Ga0.55As layer grow th. The formation mechanism for self-alignment was studied based on the num ber of In0.45Ga0.55As/GaAs multilayers, GaAs spacing layer thickness, and t he nominal thickness of In0.45Ga0.55As dot structures. Photoluminescence sp ectra showing clear polarization dependence indicate carrier coupling in QD arrays. (C) 1999 Elsevier Science B.V. All rights reserved.