Today, data has become extremely important in all aspects of human life. Currently data in computers move across chips and from chip to chip electronically, through tiny metal wires. In the context of explosive growth in data traffic, high dissipation electrical-interconnects quickly become the bottleneck due to ohmic loss and RC delays of copper wires. Already, today’s data centres are consuming about 3 percent of the global electricity supply and this number is going to be tripled in the next decade. To address these challenges, silicon photonics is progressing rapidly to realise all-optical interconnects. The use of photon-based communication in integrated circuits allows ultralow power dissipation, low latencies, and unprecedented high bandwidth. However, the lack of an efficient light emitter due to the indirect bandgap properties of silicon continues to pose a major roadblock.
In this project, we will develop quantum dot (QD) lasers directly grown on silicon at strategically important 1550 nm emission wavelength. The newly-established metal-organic vapour phase epitaxy (MOVPE) capability and the availability of molecular-beam epitaxy (MBE) provides a complementary experimental setting for this project. Various growth techniques will be investigated with the aim to improve the structural and optical properties of InAs/InP QDs. Challenges associated with integration on silicon will be addressed through development of advanced epitaxial processes including V-groove template assisted epitaxy and cavity confined epitaxy.
Feasibility of completion within 3.5 years
The project is divided into three stages:
1) literature review and MOVPE training (0.5 year);
2) Growth of InAs/InP quantum dots and optimisation of the morphology and optical properties (1 year);
3) Develop buffer technology on silicon and enable QD laser device integration (2 years).
In Stage 2 and 3, the student will interact with a PDRA from Compound Semiconductor Manufacturing Hub who will fabricate devices and provide device feedback.
Full UK/EU tuition fees plus stipend matching UKRI Minimum.
Full awards are open to UK Nationals and EU students who meet UK residency requirements. To be eligible for the full award, EU Nationals must have been in the UK for at least three years prior to the start of the course including for full-time education.
A small number of awards may also be made available to EU Nationals who do not meet the above residency requirement, provided they have been ordinarily resident in the EU for at least three years before the start of their proposed programme of study
1. Y. Han, W. K. Ng, C. Ma, Q. Li, S. Zhu, C. Chan, K. W. Ng, S. Lennon, R. A. Taylor, K.S. Wong, K.M. Lau, “Room-temperature InP/InGaAs nano-ridge lasers grown on Si and emitting at telecom bands,” Optica 5 (8), 918-923, 2018.
2. Y. Wan, J. Norman, Q. Li, M.J. Kennedy, D. Liang, C. Zhang, D. Huang, Z. Zhang, A. Y. Liu, A. Torres, D. Jung, A. C. Gossard, E. L. Hu, K. M. Lau, J. E. Bowers, “1.3 μm submilliamp threshold quantum dot micro-lasers on Si,” Optica 4 (8), 940-944, 2017. (Cover Story)
3. H. Kim, W.J. Lee, A.C. Farrell, A. Balgarkashi, D.L. Huffaker, “Telecom-wavelength bottom-up nanobeam lasers on silicon-on-insulator,” Nano letters 17 (9), 5244-5250, 2017.