"Semiconductors" are synonymous with "Silicon Chips". After all Silicon supported computing technologies in the 20th century. But Silicon is reaching fundamental limits and already many of the technologies we now take for granted are only possible because of Compound Semiconductors (CS). These include The Internet, Smart Phones, GPS and Energy efficient LED lighting! CSs are also at the heart of most of the new technologies expected in the next few years including 6G wireless, ultra-high speed optical fibre connectivity, LIDAR for autonomous vehicles, high voltage switching for electric vehicles, the IoT and high capacity data storage. CSs also offer huge opportunities for energy efficiency and net zero. CSs are often made in small quantities and using bespoke techniques and manufacturers have had to put together functions by assembling discrete devices. But this is expensive and for many of the new applications scale-up and integration, along the lines of the Silicon Chip, are needed CDT research will involve the science of large scale CS manufacturing, manufacturing integrated CS on Silicon and applying the manufacturing approaches of Silicon to CS; it will generate novel integrated functionality and all with an emphasis on finding environmentally sustainable manufacturing methods. CIVIC PRIORITY: This CDT is a fundamental part of the strategic development of the CS Cluster centred in South Wales, and in linking it to activity across the UK. It is part of a wider training strategy including apprenticeships, MScs and CPD, to train and upskill the entire workforce. The latest skills requirements have been identified by partner companies and through working with Welsh Government, CSconnected and the CS Applications Catapult The partners support the CDT financially and with their time. This is because the limiting factor to rapid cluster growth is skilled people. The expected PhD level jobs increase for the existing cluster companies alone would mop up all the students trained by this CDT. We provide a £2k stipend top-up to maximise recruitment from all backgrounds. However, the CDT does more - clusters are about cross-fertilisation of people and ideas and the CDT combines academics from 4 universities with leading and complementary expertise in CS. We form teams of two academics from different universities, one industry supervisor and the PhD student to create and carry out each PhD. The CDT also ensures the whole cohort regularly works together to exchange new knowledge and ideas and maintain breadth for each student. The UK and Welsh administrations see CS as an opportunity to boost the economy with high technology jobs and the UK government uses the CDT as part of its pitch to overseas companies to locate here. APPROACH and OUTCOMES: a 1+3 program where Year 1 (Y1) is based in Cardiff, with provision via taught lectures and transferable skills training, hands on and in-depth practical training and workshops led by University and Industry Partner staff. Following requests from Y2-4 students the industry workshops are presented in hybrid format so all Y2-4 students can further benefit from this program and where we now cycle presenters, companies and specific topics over 3 years. A dedicated training clean room allows rapid practical progress in a supportive environment, learning from doing, experts and the rest of the cohort and then an industry facing cleanroom, co-located with industry staff and manufacturing scale equipment, where students learn the future CS manufacturing skills. This maximises exchange of ideas, techniques and approach and the potential for exploitation. Both students and industry partners have praised the practical skills this produces. Y2-Y4 consist of an in depth PhD project, co-created with industry and hosted at one of the 4 universities, and specialised whole cohort training and events, including energy audit, research ethics and innovative outreach

"Semiconductors" are synonymous with "Silicon chips". After all Silicon supported computing technologies in the 20th century. But Silicon is reaching fundamental limits and already many of the technologies we take for granted are only possible because of Compound Semiconductors (CS). These include: the internet, smart phones and energy-efficient LED lighting! CSs are also at the heart of most of the new technologies envisaged, including 6G wireless, ultra-high speed optical fibre connectivity, LIDAR for autonomous vehicles, high voltage switching for electric vehicles, the IoT and high-capacity data storage. CSs also offer huge opportunities for energy efficiency and net zero. The CS Hub will contribute to "Engineering Net Zero", through products, such as energy-efficient electronics, and by introducing new environmentally-friendly manufacturing processes; to "Quantum Technologies", by creating practical implementations that can be manufactured at scale; to the "Physical and Mathematical Sciences Powerhouse" and "Frontiers in Engineering and Technology", through e.g. cutting-edge materials science and manufacturing-process innovation. CS materials are grown atom-by-atom on slices of crystalline material, known as substrates, which provide mechanical support for the resulting "wafer" during the next stage of fabrication. CSs are often made on relatively small substrates. Manufacturers have had to combine functions by assembling discrete devices but this is expensive. New approaches to integration in epitaxy and fabrication are required along with wafer-size scale-up for the new applications. Applications such as in quantum technology (QT) are pushing requirements for more accurate and highly reproducible manufacturing-processes. With such improvements CS will underpin the UK quantum industry and enable impact for the existing QT investments. We will create designs that are more tolerant to typical variations that occur during manufacturing; develop manufacturing processes that are more uniform and repeatable; create techniques to characterise performance part-way through manufacturing, create techniques to combine materials (e.g. CS grown atom-by-atom on Silicon) and combine functions on chip. We will study and implement ways to make CS manufacturing more environmentally friendly. We will make it easier to compare the environmental foot-print of different CS research and manufacturing-processes by making available relevant, high quality data in the form of accessible libraries of the resource and energy usage of the feedstocks and processes used in CS manufacturing. We aim to change the mind-set of UK academics. Our vision is that researchers think about the translation of their research from the beginning of the innovation process and about the requirements that next generation product manufacturers will face. As a critical factor in all future manufacturing, we aim to embed the philosophy of resource efficiency of the research itself, resource efficiency of the manufacturing process, as well as of the application it supports. We aim to repatriate and connect CS manufacturing supply chains to re-shore production and facilitate innovation, enabling development of holistic solutions. We will address the current staffing shortages of the CS industry by: providing leadership in improving career structure and enhancing training for Hub research and technical staff; putting in place the very best ED&I practice to create the most positive and inclusive working environment and promulgating this across the industry; inspiring the next generation of the CS workforce as well as spreading the news about the fantastic career opportunities currently available. By working closely with industry partners on all these aspects we will attract and retain staff in this critical UK manufacturing industry.

Photonics has moved from a niche industry to being embedded in the majority of deployed systems, spanning sensing, biomedical devices and advanced manufacturing, through communications, ranging from chip-to-chip and wireless access to transcontinental scale, to display technologies, bringing higher resolution, lower energy operation and new ways of human-machine interaction. Its combination with electronics enables the Digital Future. The Government's UK Semiconductor Strategy and UK Wireless Infrastructure Strategy both recognise the need for highly trained people to lead developments in these technology areas, the Semiconductor Strategy referring explicitly to the role of CDTs in filling the current shortage of highly trained researchers. Our proposed CDT has been designed to meet this need. Currently manufactured systems are realised by combining separately developed photonics, electronic and wireless components. This approach is labour intensive and requires many electrical interconnects as well as optical alignment on the micron scale. Devices are optimised separately and then brought together to meet systems specifications. Such an approach, although it has delivered remarkable results, not least the communications systems upon which the internet and our Digital Future depends, limits the benefits that could come from systems-led co-design and the development of technologies for seamless integration of photonics, electronics and wireless. Our proposed CDT aims to provide multi-disciplinary training enabling researchers to create the optimally integrated, energy efficient, systems of the future. To realise such integrated systems requires researchers who have not only deep understanding of their specialist area, but also an excellent understanding across this interdisciplinary area ranging across the fields of photonics, electronics and wireless, hardware and software. We aim to meet this important need by building upon the uniqueness and extent of the Cambridge and UCL research programmes, where activities range across materials for future systems; higher levels of electronic, photonic and wireless integration; the convergence of wireless and optical communication systems; combined quantum and classical communication systems; the application of THz and optical low-latency connections in data centres; techniques for high capacity access networks; the substitution of many conventional illumination products with photonic light sources and extensive application of photonics in medical diagnostics and personalised medicine. Future systems will increasingly rely on more advanced systems integration, and so the CDT supervisor team includes experts in electronic circuits, wireless systems and enabling software. By drawing these complementary activities together it is proposed to develop an advanced training programme to equip the next generation of very high calibre doctoral students with the required technical expertise, RRI, ES, commercial and business skills to enable the > £24 billion annual turnover UK electronics and photonics manufacturing industry to create the optimised, closely integrated systems of the future. The PES CDT will provide a wide range of learning methods for research students, well beyond that conventionally available, so that they can gain the required skills. In addition to conventional lectures and seminars, for example, there will be bespoke experimental coursework activities, educational retreats, reading clubs, road-mapping activities, RRI and ES studies, secondments to companies and other research laboratories and business and entrepreneurship courses. Students trained by the CDT will be equipped to expand the range of applications into which these technologies are deployed in key sectors of the Digital Futures and wider economy, such as communications, industrial manufacturing, consumer electronics, data processing, defence, energy, engineering, security and medicine.

TOPIC: "Semiconductors" are often synonymous with "Silicon Chips". After all Silicon supported computing technologies in the 20th century. But Silicon is reaching fundamental limits and already many of the technologies we now take for granted are only possible because of Compound Semiconductors (CS). These technologies include The Internet, Smart Phones, GPS and Energy efficient LED lighting! CSs are also at the heart of most of the new technologies expected in the next few years including 5G wireless, ultra-high speed optical fibre connectivity, LIDAR for autonomous vehicles, high voltage switching for electric vehicles, the IoT and high capacity data storage. To date CSs are made in relatively small quantities using fairly bespoke manufacturing and manufacturers have had to put together functions by assembling discrete devices. But this is expensive and for many of the new applications integration is needed along the lines of the Silicon Integrated Chip. CDT research will involve: the science of large scale CS manufacturing (e.g. materials combinations to minimise wafer bow, new fabrication processes for non-flat surfaces); manufacturing integrated CS on Silicon and in applying the manufacturing approaches of Silicon to CS. The latter includes using generic processes and generic building blocks and applying statistical process control. By applying these approaches students will address and invent new ways to exploit the highly advantageous electronic, magnetic, optical and power handling properties of CSs and generate novel integrated functionality for sensing, data processing and communication. NEED: This CDT is a critical part of the strategic development of a CS Cluster supporting activity throughout the UK. It is part of the development of a wider training portfolio including apprenticeships and CPD activities, to train and upskill the CS workforce. Evidence of the critical need for a CDT, has been identified in a survey and analysis conducted by UK Electronics Skills Foundation highlighting the specific skills required in this rapidly growing high technology industrial sector. "We are looking for PhD level skills plus industry experience. We don't have the time to train up new staff." "There are no 'perfect employees' for CS companies, as this is effectively a new area. Staff, including those with PhDs, either have silicon skills and need CS-specific training, or have CS skills and need training in volume tools and processes, either in the cleanroom or in packaging." - quotes from CS Skills Survey - Report UKESF July 2018. We have worked with the CSA Catapult utilising the skills need they have identified as well as companies across the spectrum of CS activities and are confident of the absorptive capacity: the expected PhD level jobs increase for the existing cluster companies alone would employ all the students and the CDT will support many more companies and academic institutions. APPROACH: a 1+3 programme where Year 1 is based in Cardiff, with provision via taught lectures using university approved level 7 modules and transferable skills training, hands on and in-depth practical training and workshop material supplied by University and Industry Partner staff. A dedicated nursery clean room to allow rapid practical progress, learning from peer group activity and then an industry facing environment with co-location with industry staff and manufacturing scale equipment, where they will learn the future CS manufacturing skills. This will maximise cross fertilisation of ideas, techniques and approach and maximise the potential for exploitation. Y2-Y4 consist of an in depth PhD project, co-created with industry and hosted at one of the 4 universities, and specialised whole cohort training and events, including communication, responsible innovation, entrepreneurship, co-innovation techniques and innovative outreach.

The sensing, processing and transport of information is at the heart of modern life, as can be seen from the ubiquity of smart-phone usage on any street. From our interactions with the people who design, build and use the systems that make this possible, we have created a programme to make possible the first data interconnects, switches and sensors that use lasers monolithically integrated on silicon, offering the potential to transform Information and Communication Technology (ICT) by changing fundamentally the way in which data is sensed, transferred between and processed on silicon chips. The work builds on our demonstration of the first successful telecommunications wavelength lasers directly integrated on silicon substrates. The QUDOS Programme will enable the monolithic integration of all required optical functions on silicon and will have a similar transformative effect on ICT to that which the creation of silicon integrated electronic circuits had on electronics. This will come about through removing the need to assemble individual components, enabling vastly increased scale and functionality at greatly reduced cost.