Evaluation of multi-stacked InAs/GaNAs self-assembled quantum dots on GaAs (0 0 1) grown using different As species

Abstract

We have investigated the effect of using different arsenic species on the degree of vertical self-alignment of InAs/GaNAs strain-compensated QDs in molecular beam epitaxy (MBE). We used the pairing ratio as a measure to evaluate the degree of vertical self-alignment. For the spacer layer thickness of >20nm, the QD pairing ratio for As2 sample of 53% was smaller than that for As4 of 62%. For As2 sample, we think that the QD formation is more strongly affected by surface structure with a high step density than pairing effect resulting from strain field propagation.