Axially-stacked quantum dots (QDs) in nanowires (NWs) have important applications in fabricating nanoscale quantum devices and lasers. Although their performances are very sensitive to crystal quality and structures, there is relatively little study on defect-free growth with Au-free mode and structure optimisation for achiving high performances. Here, we report a detailed study of the first self-catalyzed defect-free axially-stacked deep NWQDs. High structural quality is maintained when 50 GaAs QDs are placed in a single GaAsP NW. The QDs have very sharp interfaces (1.8~3.6 nm) and can be closely stacked with very similar structural properties. They exhibit the deepest carrier confinement (~90 meV) and largest exciton-biexciton splitting (~11 meV) among non-nitride III-V NWQDs, and can maintain good optical properties after being stored in ambient atmosphere for over 6 months due to excellent stability. Our study sets a solid foundation to build high-performance axially-stacked NWQD devices that are compatible with CMOS technologies.
@article{arxiv.2002.07071,
title = {Defect-Free Axially-Stacked GaAs/GaAsP Nanowire Quantum Dots with Strong Carrier Confinement},
author = {Yunyan Zhang and Anton V. Velichko and H. Aruni Fonseka and Patrick Parkinson and George Davis and James A. Gott and Martin Aagesen and Ana M. Sanchez and David Mowbray and Huiyun Liu},
journal= {arXiv preprint arXiv:2002.07071},
year = {2021}
}