Manufacture Using Advanced Powder Processes - MAPP Conventional materials shaping and processing are hugely wasteful and energy intensive. Even with well-structured materials circulation strategies in place to recondition and recycle process scrap, the energy use, CO2 emitted and financial costs associated are ever more prohibitive and unacceptable. We can no longer accept the traditional paradigm of manufacturing where excess energy use and high levels of recycling / down cycling of expensive and resource intensive materials are viewed as inevitable and the norm and must move to a situation where 100% of the starting material is incorporated into engineering products with high confidence in the final critical properties. MAPP's vision is to deliver on the promise of powder-based manufacturing processes to provide low energy, low cost, and low waste high value manufacturing route and products to secure UK manufacturing productivity and growth. MAPP will deliver on the promise of advanced powder processing technologies through creation of new, connected, intelligent, cyber-physical manufacturing environments to achieve 'right first time' product manufacture. Achieving our vision and realising the potential of these technologies will enable us to meet our societal goals of reducing energy consumption, materials use, and CO2 emissions, and our economic goals of increasing productivity, rebalancing the UK's economy, and driving economic growth and wealth creation. We have developed a clear strategy with a collaborative and interdisciplinary research and innovation programme that focuses our collective efforts to deliver new understanding, actions and outcomes across the following themes: 1) Particulate science and innovation. Powders will become active and designed rather than passive elements in their processing. Control of surface state, surface chemistry, structure, bulk chemistry, morphologies and size will result in particles designed for process efficiency / reliability and product performance. Surface control will enable us to protect particles out of process and activate them within. Understanding the influence between particle attributes and processing will widen the limited palette of materials for both current and future manufacturing platforms. 2) Integrated process monitoring, modelling and control technologies. New approaches to powder processing will allow us to handle the inherent variability of particulates and their stochastic behaviours. Insights from advanced in-situ characterisation will enable the development of new monitoring technologies that assure quality, and coupled to modelling approaches allow optimisation and control. Data streaming and processing for adaptive and predictive real-time control will be integral in future manufacturing platforms increasing productivity and confidence. 3) Sustainable and future manufacturing technologies. Our approach will deliver certainty and integrity with final products at net or near net shape with reduced scrap, lower energy use, and lower CO2 emissions. Recoupling the materials science with the manufacturing science will allow us to realise the potential of current technologies and develop new home-grown manufacturing processes, to secure the prosperity of UK industry. MAPP's focused and collaborative research agenda covers emerging powder based manufacturing technologies: spark plasma sintering (SPS), freeze casting, inkjet printing, layer-by-layer manufacture, hot isostatic pressing (HIP), and laser, electron beam, and indirect additive manufacturing (AM). MAPP covers a wide range of engineering materials where powder processing has the clear potential to drive disruptive growth - including advanced ceramics, polymers, metals, with our initial applications in aerospace and energy sectors - but where common problems must be addressed.

When scientists investigate problems like all good detectives they need clues as to what is happening. For a whole range of key problems, techniques that can reveal the local environment around an atom are crucial to provide insight into the structure at this level. Nuclear Magnetic Resonance (NMR) spectroscopy has increased in importance as it is an element specific probe that can distinguish very small changes in the surroundings of different sites (e.g. the number of corners by which an SiO4 unit is connected into a structure) which has become important throughout the sciences. Its major drawback is the intrinsically relatively weak signal due to the small thermally derived population differences between nuclear energy levels. NMR of solids was revolutionised with the implementation of cross-polarisation that transferred magnetisation from nuclei with high magnetic moments (e.g. 1H) to more dilute nuclei with smaller magnetic moments (e.g. 13C) that yielded a factor of ~4 increase in the 13C NMR signal strength. Today there is very significant effort with a wide range of approaches to try and increase the size of the NMR signal still further and considerable investment to achieve even a few tens of percent increase. Dynamic nuclear polarisation (DNP) is a technique that uses unpaired electron spins to boost the NMR signal by as much as 100,000. Although the effect has been known from theory and experiments at low magnetic fields for sometime, it is only now that this can be put into practice, with the whole experiment carried out at high magnetic field. This is possible now because high field magnets of sufficient flexibility and robustness can be manufactured, and the production of microwaves (similar to a microwave oven although much higher frequency) at high frequencies and with sufficient power for DNP to work at up to 395 GHz is becoming feasible. This proposal seeks to bring this technology together in a new instrument to now carry out DNP at magnetic fields up to 14.1 T on solid materials and to develop the technology to use both continuous wave and pulsed DNP at these fields. Huge gains in sensitivity will result from both the DNP effect itself which in thermal equilibrium, could offer potential enhancements of the ratio of the gyromagnetic ratio of the electron to that of the nucleus, a factor of >2500 for 13C, combined with MAS operation at ~90K further increasing the enhancement via the thermal Boltzmann factor. The instrument would produce DNP at NMR frequencies much beyond those yet reported and thus allow modern high resolution solid state NMR experiments to be undertaken with gains over conventional NMR of 100-1000 routinely expected. Quadrupolar nuclei (especially those with non-integer spins), which make up >75% of the NMR-active nuclei, have largely been precluded from DNP because the nuclear resonance is too broad at current DNP magnetic (Bo) fields. This second-order quadrupolar broadening demands the use of high Bo and the instrument proposed here would have sufficiently high Bo to open up their study by DNP. The wide frequency capability of the instrument would provide new insight into the physics of high field DNP allowing, for the first time, an optimum technology to be developed in this emerging field. The versatility of the instrument proposed means that, with the same equipment, one could also carry out world-leading pulsed EPR and ENDOR experiments. The project is driven by the multidisciplinary applications in areas of huge importance as diverse as structural biology and fuel cell/electrochemistry technology. The DNP approach will allow NMR to be considered where hitherto sensitivity would have prohibited its use because of the sample size and/or the number of spins of interest are limited. The development of this technology would have an immediate and profound effect on UK research capability in a number of key areas of science and technology.

For centuries diamond has been highly sought after for manufacture into gem stones; the demand stems from its exemplary physical properties. Such remarkable characteristics also render diamond a promising host medium for many advanced technology applications. With recent breakthroughs in the manufacture of synthetic diamond substrates, the adoption of diamond into widespread device application is becoming ever more tangible. However, there is an urgent need for a scalable processing framework that can turn this hard, inert material into functional devices. In the course of this fellowship, I will develop a diverse toolkit based around laser fabrication which can fill this void. Through the use of short pulsed lasers and advanced optical techniques, accurate fabrication in three dimensions beneath the surface of diamond becomes possible. Dependent on the laser power and how it is focused into the diamond, different processing regimes are possible. Electrically conductive wires may be printed in 3D running through the diamond, as can optical wires for routing light through the diamond. By reducing the laser power, it is possible to introduce just a single defect in the diamond lattice which can then be used as an information bit for quantum processing. Devices manufactured will include detectors of high energy radiation for use at CERN, 3D arrays of defects for quantum enhanced sensing and 3D photonic structures for manipulation of light. This will deliver a route to commercial diamond technology as well as a set of optical fabrication protocols that are transferable across wide technological areas. The bulk of the work will be carried out at the Department of Engineering Science at the University of Oxford. There will be close collaboration though with partners at the Universities of Manchester, Warwick and Strathclyde, harnessing their unique capabilities to develop a complete photonics system for the creation of advanced technology devices in diamond.

Solid state electronic devices have transformed our lives over the past fifty years: the development of devices like the transistor, integrated circuits and magnetic hard disks have given us a revolution in computing power, portable electronics and the ability to store and handle vast amounts of data. Quantum technologies aim to harness the power of quantum physics to deliver a further revolution in areas such as computing, sensing and communication. The UK is currently making a major investment in the exploitation of quantum science research to deliver a range of quantum technologies - so far this investment has focused on platforms of photonics, cold atoms and trapped ions. The aim of our proposal, Quantum Engineering of Solid-State Technologies, or QUES2T, is to address the capability gap in in quantum solid-state technologies and ensure the UK is in a strong competitive position in some of the most high-impact and scalable quantum technologies. In QUES2T we focus on three solid-state platforms which are well-poised to make significant commercial impact: i) silicon nano-devices, ii) superconducting circuits and iii) diamond-based devices. Each of these materials have demonstrated outstanding properties: silicon can store quantum information for a record-breaking 3 hours, superconducting circuits have been used to make the most complex quantum devices to date, while diamond based magnetometer have a sensitivity to image individual proton spins in a second. We will exploit these properties to develop practical quantum technologies. Importantly, we do not consider these platforms in isolation. A key strength and unique feature of QUES2T is that it not only provides essential infrastructure in each of these three areas but that it brings together a team of people with expertise across these different platforms. This will allow exchange of cross-fertilisation of different disciplines through transfer of expertise and the accelerated development of hybrid technologies that combine the best properties of different materials, to make new detectors, memories, and processors. QUES2T will allow UK researchers and their collaborators to exploit the advantages of developing new quantum devices based on solid state technologies, including easier integration with existing conventional technologies (such as CMOS processors) and reduced timescales to market and manufacturing. The capital infrastructure of QUES2T will establish world-class fabrication capabilities to manufacture high-quality quantum device prototypes out of a range of materials. It will also enable the creation of low-temperature technology test-beds to test the prototypes and develop technology demonstrators. These test-beds will combine a number of essential features, enabling devices to be addressed optically using lasers, with microwave pulses, under low-noise electrical measurements, and all at a hundredth of a degree kelvin. Such systems will be unique UK. To deliver our vision, we have established strong links with academic and industrial partners to exchange the latest technology, expertise and materials. Examples are ultra low-phase noise signal generators with applications in fast high-fidelity qubit control or isotopically pure materials for quantum prototypes in Si and diamond. Industry users working on quantum technologies will be actively encouraged to access the QUES2T infrastructure, such as a state-of-the-art 100 keV electron beam writer to make devices with 10nm features. Many industry partners will also be end users of the technologies that will be developed through QUES2T. Early technologies include scanning probe devices enabling magnetic resonance imaging at the single molecule level and quantum current standards counting electrons one-by-one. On a longer timescale, a fault-tolerant and scalable Si or superconducting based quantum processor, would be form the basis of a new and disruptive industry in computing.

The high breakdown voltage and large sheet carrier density of GaN based HEMTs provide major advantages for rf and microwave systems owing to their power handling capability. These advantages have also underpinned the emergence of GaN based components for low frequency power electronics. The latter is a major growth area as energy efficiency and sustainability become critical factors in the design of electrical systems. The overwhelming cause for reduced electrical power efficiency in active electronic components and systems is unwanted increases in operating temperature, which degrade power gain in amplifiers, the internal quantum efficiency of light emitting diodes and power conversion efficiency of diode lasers. As an example of the impact device heating on system efficiency, about 70% of the electrical power consumed by mobile telephone transmitter is wasted as heat owing to Joule heating in the electronics and consequent reductions in power gain of its constituent transistors. The most effective way to limit the temperature rise of a semiconductor device is to introduce high-thermal conductivity heat spreading layers as close as possible to its active region, for example over the top of the device or growing the device structure on a thermally conducting substrate. Typically GaN based HEMTs of the type used in rf circuits and high power electronics are grown on SiC or increasingly Si wafers substrates. Whilst SiC is a better thermal conductor than Si, polycrystalline or crystalline diamond are far superior, better even than metals. Recently GaN HEMT grown on crystalline diamond substrates have been recently demonstrated. However, the small size (5 x 5 mm) of current crystalline diamond (PD) substrates and their high cost prohibit this ideal approach. Thus, a polycrystalline diamond substrate offers the best solution. The calculations show that the larger thermal conductivity of polycrystalline diamond could bring to power HEMT performance compatible or better than that on SiC or Si substrates. To date, the most widely investigated method of exploiting PD substrates in GaN power HEMT technology has been to grow the III-Nitride layers on a Si substrate, then transfer the epitaxy to carrier substrate and finally bonding the device layers to the PD wafer. The procedure involves two wafer bonding steps, a process that requires minimal wafer bow if breakage is to be avoided, something that is difficult to achieve owing to the lattice mismatch between Si and III-Nitride materials. There is also a tendency for the final structure to delaminate and despite several years of development by companies like Group4Labs, SOITEC and Nitronex, commercial products are still not established. To overcome these difficulties, an alternative approach has been developed by the Applicants in collaboration with Element 6. Briefly, this involves forming a composite structure comprising a thin layer of Si on a thicker layer of polycrystalline diamond, intimately contacted without wafer bonding. The upper Si surface is suitable for immediate III-Nitride growth. More information is given in section 3. One patent application has already been filed (world wide) and a second is in preparation; in both instances Bath has assigned its rights to Element 6. Independently of Element 6 and other parties, Bath has developed methods for growing III-Nitride hetero-epitaxy on these complex Si/PD substrates. The results of applying these methods to realise high quality III-Nitride epitaxial layers on Si/PD substrates has recently been reported in ICNS9, critical details in the process were not disclosed and thus the opportunity exists to create an intellectual property portfolio covering the realisation of device grade III-Nitride epitaxial films on Si/PD heat extracting substrates to complement the very separate existing IP covering the manufacture of the latter. The new knowledge will be owned in its entirety with the University of Bath.