Li, Keshuang;
(2022)
III-V Quantum Dot Lasers Monolithically Integrated on On-axis Si Substrates.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The monolithic integration of high-performance III-V QD lasers on Si substrates has been considered as a promising way to develop the on-chip optical sources, featuring on the outstanding advantages of low cost, high-energy efficiency and high temperature stability. In this thesis, the realization of electrically pumped 1.3 µm QD laser directly grown on complementary metal-oxide-semiconductor (CMOS) compatible Si (001) substrate with different approaches has been demonstrated. First, to optimize the QD active region, we investigated the effect of various growth conditions, such as temperature, growth rate, and V/III ratio, on the quality of epitaxial layer, and achieved high-quality QD layers with QD density of over 5.9×1010 cm-2 and photoluminescence linewidth of 30 meV. With the antiphase boundary (APB) free GaAs/Si virtual substrate grown by metal-organic chemical vapour deposition (MOCVD), a high-performance 1.3 µm InAs/GaAs QD laser with optimized III-As buffer layer has been demonstrated, producing a threshold current density as low as 160 Acm-2 under continuous-wave mode. In addition, a novel method for achieving APB free III-V materials on CMOS compatible Si (001) platform by only MBE system is demonstrated. APB-free GaAs grown on on-axis Si substrate has been achieved within 1 µm buffer layer by employing an annealed 200 nm Si buffer layer on Si substrate with periodic single atomic height Si steps and an optimized III-V buffer growth method. A high performance 1.3 µm InAs/GaAs QD laser with low threshold of 83.3 Acm-2 and maximum operation temperature of 120 °C under pulse operation has been successfully demonstrated upon on-axis Si (001) substrate. These works significantly improved the property of InAs/GaAs QDs and simplified the growth requirement for high quality QD lasers monolithically integrated on Si, providing major breakthrough towards the Si-based photonics integrated circuits.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | III-V Quantum Dot Lasers Monolithically Integrated on On-axis Si Substrates |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10143972 |
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