Journal
NANOPHOTONICS
Volume 11, Issue 8, Pages 1515-1526Publisher
WALTER DE GRUYTER GMBH
DOI: 10.1515/nanoph-2021-0482
Keywords
near-infrared spectroscopy; quantum dots; quantum telecommunication; single-photon sources
Categories
Funding
- Danish National Research Foundation via Research Centre of Excellence NanoPhoton [DNRF147]
- Polish National Science Center [2020/36/T/ST5/00511]
- European Union under the European Social Fund
- St. Petersburg State University [75746688]
Ask authors/readers for more resources
The development of quantum communication technology requires quantum emitters that can generate single photons and entangled photon pairs. This study successfully synthesized low surface density InAs x P1-x quantum dots with symmetric profiles using droplet epitaxy, which can contribute to the fabrication of versatile quantum emitters.
The rapidly developing quantum communication technology requires deterministic quantum emitters that can generate single photons and entangled photon pairs in the third telecom window, in order to be compatible with existing optical fiber networks and on-chip silicon photonic processors. InAs/InP quantum dots (QDs) are among the leading candidates for this purpose, due to their high emission efficiency in the required spectral range. However, fabricating versatile InAs/InP QD-based quantum emitters is challenging, especially as these QDs typically have asymmetric profiles in the growth plane, resulting in a substantial bright-exciton fine structure splitting (FSS). This hinders the generation of entangled photon pairs and thus, compromises the versatility of InAs/InP QDs. We overcome this by implementing droplet epitaxy (DE) synthesis of low surface density (2.8 x 10(8) cm(-2)) InAs x P1-x QDs with x = (80 +/- 15)% on an (001)-oriented InP substrate. The resulting QDs are located in etched pits, have concave bases, and most importantly, have symmetric in-plane profiles. We provide an analytical model to explain the kinetics of pit formation and QD base shape modification. Our theoretical calculations of electronic states reveal the properties of neutral and charged excitons and biexcitons confined in such QDs, which agree with the optical investigations of individual QDs. The optical response of QDs' ensemble suggests that FSS may indeed be negligible, as reflected in the vanishing degree of linear polarization. However, single QD spectrum gathered from an etched mesa shows moderate FSS of (50 +/- 5) mu eV that we link to destructive changes made in the QD environment during the post-growth processing. Finally, we show that the studied DE QDs provide a close-to-ideal single-photon emission purity of (92.5 +/- 7.5)% in the third telecom window.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available