Manufacturing scalable semiconductor quantum light sources

Semiconductors have already revolutionised the world around us through the inventions of the transistor, diode lasers, integrated circuits and sensors. A new wave of semiconductor quantum technologies are finding commercial applications in ultra-secure communications, enhanced imaging, sensing, and possibly even computing and simulations. In all these cases the "quantum advantage" is theoretically proven and experimentally demonstrated, but there is a strong need for a scalable, practical and efficient source of quantum light.

Naturally occurring point-like light sources called "colour centres" act as quantum light sources in wide bandgap semiconductors such as diamond, Silicon Carbide, Boron Nitride and Gallium Nitride (GaN) at room temperature. Commercially, GaN now dominates the market for solid state lighting, because it is an efficient and manufacturable material, leading to costs of less than one dollar per LED. However, Gallium-Nitride is also a promising material for quantum light sources as the colour centres within it emit from the ultra-violet to the near infra-red. This wide range means the emission overlaps with minima in the absorption curves of optical fibres (1310 and 1550 nm), transitions in the best atomic quantum memories (near 800nm) and low loss free-space communications in the blue. Furthermore, by engineering heterostructures within the semiconductor it is possible to electrically drive the emitter, rapidly switch the device and design efficiency-enhancing structures.

This fellowship will apply manufacturing techniques widespread in the compound semiconductor manufacturing field, such as large area epitaxy and wafer scale processing, to deliver a bright and room temperature quantum light-emitting diode based on GaN. I will use laser lithography, standardised packaging and quality control to ensure the end device is produced in a manner that enables scale up to mass-production, with the full supply chain within the UK. Collaboration with the UK semiconductor industry for growth and packaging of devices, and use of processing facilities installed at Cardiff University, will foster two-way knowledge exchange between industry and academia. My experience of this type of collaboration at Imperial-Agilent and at Toshiba-Cambridge, makes me uniquely well-qualified to manage this interaction. By funding me to devote a significant amount of my time to research for the next 5 years this project will deliver high impact research and build a platform for future UK prosperity and technological know-how.

ECONOMIC IMPACT

This proposal will support the UK economy by generating intellectual property, know-how and a low cost, practical quantum-LED prototype. By keeping the quantum-LED fully integrated into the UK's supply chain I will deliver a device ready to be incorporated in commercial systems. An Advisory Panel of experts will advise me throughout, ensuring the project addresses the challenges of manufacturing, packaging and testing. This will generate spin-off benefits to conventional GaN-LED manufacturing, creating wealth in the UK.

The impact of the research will be maximised through protection of intellectual property, if appropriate. Previously I have worked on 15 patent families, and so am attuned of the requirements to protect valuable ideas at an early stage. Project partners TREL and idQuantique are the UK's leading companies in optical quantum technology, and offer a route to commercialisation (see Letters of Support).

SOCIETAL IMPACT

I will develop an enabling technology for applications in quantum communications, imaging and sensing. Quantum technologies have the potential to transform the UK with quantum key distribution offering personal communications secured by the laws of physics and quantum imaging offering unprecedented functionalities for autonomous cars' LIDAR.

I will use my membership of the consortium running the second phase of the UK National Quantum Computing and Simulation Hub to keep up to date with the most challenging application areas. I will also show system-ready devices at the UK National Quantum Technology Showcase, held annually in London, seeking collaborators and end-users.

Through the School of Engineering Public Engagement Office I will arrange to present in front of the Welsh Assembly STEM working group on QT and at the "Science in the Senedd" events, where Assembly Members, journalists and the public are present. I will undertake communications training prior to these events to ensure I maximise impact.

IMPACT IN KNOWLEDGE TRANSFER

This fellowship will enable me to transfer my knowledge and expertise by training PhDs and Postdocs to have the skills suitable for employment in research and development, further supporting an area of the UK economy facing an acute skills shortage. Trained experts are essential to maintain and grow the UK's engineering base and foster a strong, resilient and healthy nation.

The project is located in South Wales, where numerous initiatives in the field of Compound Semiconductors (CSs) are coordinated under the umbrella organisation "CS Connected". In particular, the CS Centre Ltd. will be used to grow the material used in this project. The CS Applications Catapult will package devices into robust, standardised housings that are essential for future incorporation into systems. Processing will occur in the University's Institute for CSs (ICS) cleanroom, which has a wafer scale processing line for GaN LEDs. Thus, the possibility of scaling up production of devices exists within a half hour journey from Cardiff. This cluster of expertise in the local area makes the project well placed to link into other initiatives in CSs. To push this I will showcase the project at regular events organised by partners of CS Connected, such as the annual Co-Innovate conferences organised by IQE plc.

PUBLIC ENGAGEMENT

Quantum Technology is an area that generates considerable public interest, and this work will be promoted with social media (@BennettLabCardiff), group webpage, press releases, topical reviews in general interest science/engineering magazines and through engagement with science journalists. I will also develop a show on the science of mobile phones with Cardiff social enterprise Science-made-Simple for use in secondary schools and science fairs. This will introduce students to the concepts of coloured LEDs, radiation and crystals through a technology they are excited about.