Epitaxial GaAs quantum dots grown by droplet etching have recently shown excellent properties as sources of single photons as well as entangled photon pairs. Integration in some nanophotonic structures requires surface-to-dot distances of less than 100 nm. This demands a surface passivation scheme, which could be useful to lower the density of surface states. To address this issue, sulphur passivation with dielectric overlayer as an encapsulation is used for surface to QD distances of 40 nm, which results in the partial recovery of emission linewidths to bulk values as well as in the increase of the photoluminescence intensity.
@article{arxiv.2202.02655,
title = {Surface passivation and oxide encapsulation to improve optical properties of a single GaAs quantum dot close to the surface},
author = {Santanu Manna and Huiying Huang and Saimon Filipe Covre da Silva and Christian Schimpf and Michele B. Rota and Barbara Lehner and Marcus Reindl and Rinaldo Trotta and Armando Rastelli},
journal= {arXiv preprint arXiv:2202.02655},
year = {2022}
}