Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic properties
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 qu...
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| Language: | English |
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De Gruyter
2022-01-01
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| Series: | Nanophotonics |
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| Online Access: | https://doi.org/10.1515/nanoph-2021-0482 |
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| author | Holewa Paweł Kadkhodazadeh Shima Gawełczyk Michał Baluta Paweł Musiał Anna Dubrovskii Vladimir G. Syperek Marcin Semenova Elizaveta |
| author_facet | Holewa Paweł Kadkhodazadeh Shima Gawełczyk Michał Baluta Paweł Musiał Anna Dubrovskii Vladimir G. Syperek Marcin Semenova Elizaveta |
| author_sort | Holewa Paweł |
| collection | DOAJ |
| description | 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 × 108 cm−2) InAsxP1−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) µeV 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. |
| format | Article |
| id | doaj-art-8204ca94a48743b9a49e936a39078157 |
| institution | Kabale University |
| issn | 2192-8614 |
| language | English |
| publishDate | 2022-01-01 |
| publisher | De Gruyter |
| record_format | Article |
| series | Nanophotonics |
| spelling | doaj-art-8204ca94a48743b9a49e936a390781572024-11-25T11:19:07ZengDe GruyterNanophotonics2192-86142022-01-011181515152610.1515/nanoph-2021-0482Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic propertiesHolewa Paweł0Kadkhodazadeh Shima1Gawełczyk Michał2Baluta Paweł3Musiał Anna4Dubrovskii Vladimir G.5Syperek Marcin6Semenova Elizaveta7DTU Fotonik, Technical University of Denmark, Kongens LyngbyDK-2800, DenmarkDTU Nanolab-National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Kongens LyngbyDK-2800, DenmarkDepartment of Theoretical Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, 50-370Wrocław, PolandLaboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370Wrocław, PolandLaboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370Wrocław, PolandFaculty of Physics, St. Petersburg State University, Universitetskaya Embankment 13B, 199034, St. Petersburg, RussiaLaboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370Wrocław, PolandDTU Fotonik, Technical University of Denmark, Kongens LyngbyDK-2800, DenmarkThe 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 × 108 cm−2) InAsxP1−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) µeV 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.https://doi.org/10.1515/nanoph-2021-0482near-infrared spectroscopyquantum dotsquantum telecommunicationsingle-photon sources |
| spellingShingle | Holewa Paweł Kadkhodazadeh Shima Gawełczyk Michał Baluta Paweł Musiał Anna Dubrovskii Vladimir G. Syperek Marcin Semenova Elizaveta Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic properties Nanophotonics near-infrared spectroscopy quantum dots quantum telecommunication single-photon sources |
| title | Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic properties |
| title_full | Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic properties |
| title_fullStr | Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic properties |
| title_full_unstemmed | Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic properties |
| title_short | Droplet epitaxy symmetric InAs/InP quantum dots for quantum emission in the third telecom window: morphology, optical and electronic properties |
| title_sort | droplet epitaxy symmetric inas inp quantum dots for quantum emission in the third telecom window morphology optical and electronic properties |
| topic | near-infrared spectroscopy quantum dots quantum telecommunication single-photon sources |
| url | https://doi.org/10.1515/nanoph-2021-0482 |
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