In 2019 48.5% of the 32 GW daily average energy demand in the UK was carbon-free - contributed by wind farms, solar and nuclear energy, alongside energy imported by subsea interconnectors and biomass. This trend supports the "net zero" commitment signed by the government in 2019. However, significant technologies still need to be developed to enable this goal. One key such technology is high voltage direct current (HVDC) grid level transmission which will enable the "supergrid". This is a network of long distance power transmission lines across and between countries and those aforementioned energy production facilities, particularly in remote locations such as offshore wind farms. Increasing the efficiency and power rating of each grid interconnection (as well as reducing their volume and weight) it would mean more widespread implementation and hence better energy security, lower carbon footprint and better energy economy for the UK. Within most interconnectors, 50% of the volume is the power electronics devices, traditionally made from Silicon technology. Silicon Carbide (SiC) has clear advantages over current Silicon technology such as high temperature and higher frequency operation, with lower resultant system weight and volume. Recently, commercially available SiC power devices have recently entered the market with force, predicted to be worth $2bn by 2024, with rapid growth in this technology is being actively driven by a number of early adopters in the automotive sector, e.g. Tesla. However for high voltage (>1.7 kV) power transmission, bipolar Silicon devices (IGBTs, GTOs) are more efficient - so the technology must presently be chosen relative to application. To remove this restriction, SiC power devices of all types can be additionally bolstered by SuperJunction (SJ) technology, improving the efficiencies of the material and fully ready to challenge Si technology. This proposal intends on developing new 6.5 kV SiC SJ materials and devices technology for the goal of increased power transmission. Current research in SiC SJ devices consists only of a handful of reports on single devices, whilst encouraging, the technology is still in its infancy. The UK has an opportunity to develop the technology from the ground up and become a serious international name. The major challenge being that SiC processing methods fall short of being able to mass-produce the superjunction material, with one method being expensive and complicated, another requiring very tight precision of parameters and the last compromising on current rating. Specifically here we propose to develop Trench Epitaxy (TE), which deposits crystalline materials in very high aspect ratio micro trenches. The deposition method is chemical vapour deposition (CVD), which is accepted as the industry gold standard of fast throughput, high quality materials production and so must be the method of choice when developing this technology. The challenges in developing TE lie in the transport of the gases to the bottom of the trenches to a) etch the material, b) condition it ready for deposition and c) fully refilling the trenches with modified material and d) ensuring the surface is returned to its previous state. The more complex challenges lie in the non-mutually exclusive chemical nature of the work, where a change in one parameter may change many more. Warwick currently houses the only industrial SiC CVD in the UK, has a dedicated SiC device fabrication cleanroom and many analytical tools so is the ideal place for the UK to enter this field with the view to contributing to the technology at the point of entry. The University of Warwick is a key member of EPSRC Centre for Power Electronics and is part of the £17M APC-12 ESCAPE (End-to-end Supply Chain development for Automotive Power Electronics) project which is developing a UK centred SiC production line, led by McLaren, so pathways exist of fully implementing TE SiC SJ technology after development.

The iridescent colours often seen in nature in butterfly wings, beetle carapaces and cuttlefish mating displays are a result of the wave nature of light which can show constructive and destructive interference effects for different colours. We can make in the lab repeated structures where the repeat period is close to the wavelength of light and see similar effects; a well-known example being the reflection from a compact disc but also the opposite effect is seen in the anti-reflection coating applied to spectacles which can be seen in the violet coloured high angle reflections. In fact, the angular sensitivity of these diffractive reflection effects can lead to wonderful rainbow reflective colour displays, while some three-dimensional structures such as butterfly wings suppress this angular change; as in the case of the famous blue morphospecies which maintains a largely blue wing colour while flying. In this project, we aim to build three-dimensional repeating structures that can lead to very strong reflection effects while reducing the angular changes normally seen with two-dimensional gratings and mirrors. These 3D periodic materials can effectively reflect light incident from any angle for a particular range of colours (wavelengths) and essentially block light from passing through the material in any direction. These materials are known as photonic bandgap materials because they block a band of colours and because they have properties analogous to the semiconductor bandgaps that block electrons travelling in certain energy bands. Although difficult to fabricate, these materials could exhibit quite striking and useful effects. For instance, blocking all transmission in all directions could be used as protection against bright light (e.g. lasers) or the bandgap could be made sensitive to certain molecular species or pollutants providing a sensing modality. In our team, we have been looking at the light trapping properties of these materials and their effect on light emission. For instance, if a fluorescent dye molecule with emission band entirely within the bandgap is excited inside such an ideal material then it will have no route by which to emit light and remain in its excited state until decaying by a non-radiative route. However, if we create a cavity by removing a small amount of material, the light emission will occur but will be trapped in this cavity until absorbed or leaking through the finite barrier to the edge of the material. Theoretically, these storage times can be very long while the cavity volumes can be made very small which can lead to a strong enhancement of emission and absorption of light by the fluorophore, so-called 'strong coupling' predicted by the full quantum mechanical treatments of the light-matter interaction. Finally, in this project, we will develop reliable techniques to make these 3D light confining materials and exploit their novel properties to trap light in tiny 'cavities' and waveguides thus showing the strongest light-matter interactions possible. These results will have an impact across the board from creating new light sources containing single 'atom' like emitters through to the smallest lasers and materials mimicking the reflectivity of butterfly wings.

Increasingly conventional materials are not able to meet the performance levels required by new technologies. We need new materials with combinations of extraordinary properties that enable scientists and technologists to achieve the otherwise impossible. Diamond is one such super-material, which can be synthesized with ever-increasing control over the exploitable properties. The synthesis of diamond is currently an area where the UK leads the world. Examples of applications include exploitation of (i) ultra/isotopically pure diamond for quantum, photonic and electronic technologies including diamonds functionalised with ensembles of nitrogen-vacancy defects for magnetic imaging of living cells, magnetic navigation and solid-state masers; (ii) heavily boron-doped diamond for electrochemical sensing (in both hostile and biological environments) and water treatment; (iii) large diamond optical elements for next-generation lasers where diamond is an active intra-cavity element rather than just a window; (iv) polycrystalline diamond for acoustic and for thermal management applications ranging from power electronics to 5G communications. Seizing the scientific and commercial opportunities of Diamond Science and Technology (DST) and staying ahead of stiff global competition, requires coordinated research at TRL 1-3, capture and protection of UK generated IP and researchers who can tackle multi-disciplinary challenges head-on. The proposed Prosperity Partnership would ensure that the UK's scientific and technological lead in DST is not eroded. The programme of research and collaboration is split into three work-packages (WPs). WP1 focusses on the synthesis, characterisation, and exploitation of perfect diamond in which the maximum exploitable properties are unleashed because deleterious impurities and defects which cause problematic strain are removed. Larger-area single crystal CVD diamond will be grown since diamond's immense potential is limited in many application areas by the small sizes currently available. Functionalised diamond will also be produced where the useful defects have been controllably introduced. WP2 concentrates on the development of processing, functionalisation, and integration technologies for diamond. Growing the diamond is not enough: we have to develop the tool kit that enables processing of diamond into the desired geometrical structure, integration with other materials and suitable packaging that in no way limits performance advantages. WP3 addresses the challenge of quality assurance such that end users know that the packaged material properties meet their requirements, and that the material can be reproducibly produced at a reasonable cost. Also, in WP3 we will produce proof of concept devices that show the potential and seed new product development. The project outcomes will include new materials with improved and tailored properties, new science enabled by enhanced intrinsic properties and the ability to manufacture innovative diamond devices. The significant impacts of the work will be in the new materials and processes demonstrated, increased confidence in others to exploit diamond because we have established a complete diamond supply chain (from production of the material to integration in devices, whilst still retaining the required properties) and the commercialisation of the breakthroughs by partner companies. The new scientific understanding generated by the research will allow us to create innovative and disruptive technologies: we are focused on maximizing the impact of this research and technology development to the greatest benefit of our society. The deliverables of our research programme address many of the major challenges facing us today and we will, in collaboration with the Centre for Doctoral Training in DST, promote the impact of DST research (and STEM in general) via a number of outreach activities. We will actively embrace, at all levels, equality, diversity and inclusion.

Southampton and Glasgow Universities currently contribute to a project entitled CORNERSTONE which has established a new Silicon Photonics fabrication capability, based on the Silicon-On-Insulator (SOI) platform, for academic researchers in the UK. The project is due to end in December 2019, after which time the CORNERSTONE fabrication capability will be self-sustaining, with users paying for the service. Based upon demand from the UK's premier photonics researchers, this proposal seeks funding to extend the capability that is offered to UK researchers beyond the current SOI platforms, to include emerging Silicon Photonics platforms, together with capabilities facilitating integration of photonic circuits with electronics, lasers and detectors. These emerging platforms enable a multitude of new applications that have emerged over the past several years, some of which are not suitable for the SOI platform, and some of which complement the SOI platform by serving applications at other wavelengths. Southampton, and Glasgow universities will work together to bring the new platforms to a state of readiness to deliver the new functionality via a multi-project-wafer (MPW) mechanism to satisfy significantly increasing demand, and deliver them to UK academic users free of charge (to the user) for the final six months of the project, in order to establish credibility. This will encourage wider usage of world class equipment within the UK, in line with EPSRC policy. We seek funding for 3 PDRAs and 2 technicians across the 2 institutions, over a 2 year period, to facilitate access to a very significant inventory of equipment at these 2 universities, including access to UK's only deep-UV projection lithography capability. During this 2 year period, we will canvas UK demand for the capability to continue to operate as an EPSRC National Research Facility, and if so, to establish a statement of need. We currently have 50 partners/users providing in-kind support to a value of to £1,705,000 and cash to the value of £173,450.

Undeniably, there are numerous crystal materials that surpass Silicon based devices (such as Gallium Nitride, Silicon Carbide and Diamond), but the high cost of their manufacturing has always been the roadblock for their implementation in applications therefore nowadays Silicon dominates the semiconductor industry. Gallium nitride (GaN) is a more superior semiconductor to Silicon for RF and Power applications. The advantage of GaN is that it can be grown as a thin layer on top of a standard low-cost Silicon wafer (i.e. substrate) enabling a new power device family, Power High Electron Mobility Transistors (HEMTs) on Silicon. Power HEMTs are faster, compact in size, more efficient and comparable in price for converter applications to their aging Silicon counterparts. Similarly to Silicon power technology development (from discrete devices to smart power integrated circuits), the arrival of GaN-based integrated circuits, GaN power transistors monolithically integrated with Hall-effect and temperature sensors, GaN gate drivers and ASICs, will facilitate widespread use of gallium nitride technology for high-volume applications. The GaN Smart Power Integrated Circuit Technology (GaN SPICe) project brings together the Universities of Coventry and Glasgow to investigate, develop and provide functional verification of the game-changing GaN smart power integrated technology; the group will be the 1st in the World to integrate a normally-off power GaN HEMT with advanced galvanic Hall-effect and temperature sensors. HEMT is a voltage controlled device and on-chip monitoring of its output current is critical for safe and long operation of an electronic system, similar to monitoring one's heart rate. The galvanic sensor is a GaN Hall-effect device accompanied by signal conditioning circuitry (with Coventry's filed patent application number 1913936.9), to minimise drift in sensor characteristics at elevated temperatures. This will increase functionality, enable a reduction of system volume, reduce cost of assembly, and as chip temperature can be actively compensated, improve reliability and efficiency of the power device. These are fundamental requirements for complex power electronics systems, in particular when installed in limited volume, hostile (high temperature/vibration) environments, such as battery electric and hybrid vehicles for example. Coventry and Glasgow are uniquely positioned to make this project success, thanks to the track record and expertise of its academic and research staff, GaN power HEMT at Glasgow and GaN Hall-effect sensors at Coventry, and the investment in their laboratory facilities (clean room, design, and test and characterisation laboratories), making it one of very few research consortiums, in the UK and overseas, capable of providing innovation at every stage of this development.