The combination of extreme electronic and thermal properties found in synthetic diamond produced by chemical vapor deposition (CVD) is raising considerable excitement over its potential use as a semiconductor material. Experimental studies have demonstrated charge-carrier mobilities of >3000cm2V-1s-1 and thermal conductivities >2000 Wm-1K-1. The material has been predicted to have a breakdown field strength in excess of 10 MVcm-1. These figures suggest that, providing a range of technical challenges can be overcome, diamond would be particularly well suited to operation as a semiconductor material wherever high frequencies, high powers, high temperatures or high voltages are required. This proposal addresses the novel use of 'delta-doping' to realise such devices.In conventional device technology a major limitation to the magnitude of mobility values within a given semiconductor is the presence of ionised impurities which cause carrier scattering. However, it is these ionised impurities that are the origin of the free carriers within n- or p-doped material. It is the physical separation of the impurities from the free carriers, such that less scattering occurs and mobility values increase, that lies at the heart of recent improvements in high frequency device performance using III-V semiconductor technology. One approach to achieve this the formation of very thin, highly doped regions within a homostructure. Provided the doped, or d, layer is only a few atom layers thick, carriers will move in a region close to, but outside, this layer. The resultant separation between carriers and the donor/acceptor atoms that created them leads to enhanced mobility. The advantages offered by d doping in other systems will be valid for diamond, with the additional feature that the problem with the large activation energy of boron can be overcome, as very high concentrations are desirable in the d-layer. However, the molecular beam epitaxy (MBE) techniques that can be used for III-V semiconductor growth cannot be used with diamond; the need to use plasma-enhanced CVD processes significantly complicates the approach needed to realise atomic-scale modulation-doped diamond structures.While Si and GaAs devices dominate the solid-state microwave device market, they cannot match the power performance of the vacuum tube. One driver for diamond as a semiconductor stems from an interest in replacing vacuum tubes in niche applications. The development of a solid-state alternative would have many benefits including small size, low weight, low operational voltage (compared with vacuum tube devices), and greater robustness. Current vacuum tube designs, such as magnetrons, klystrons, and traveling-wave tubes (TWT) are usually bulky, often fragile, and expensive (with the exception of magnetrons for microwave ovens, which are manufactured in huge volumes and cost only $10-20/kW). If the intrinsic properties of diamond could be fully exploited through novel delta-doped device design and fabrication, it could compete not only with existing wide-bandgap devices (based on SiC and GaN) but also with TWTs in the entire radio frequency (RF) generation market up to 100 GHz. The control of power at high voltages is another potential use of the diamond devices that may arise from the proposed programme of study. Theoretically, a single diamond switch could be used to switch power at voltages approaching 50 kV. This is not currently achievable with any other electronic material.

The underlying remarkable material properties of diamond offer the prospect for semiconductor devices with extraordinary potential in high power applications, as well as those requiring operation at high temperature and in high radiation environments. However, despite their tremendous potential, the progress in developing diamond high voltage devices has been severely impeded by challenges associated with the availability of good quality substrates, limitations in thick and high quality epilayer growth and advanced device processing technologies . Moreover, advances have been additionally hampered by the lack of shallow n-type dopant species. However, recent progress by the applicants in developing diamond technologies make these above listed challenges considerably reduced enabling further advances in pursuit of developing high power diamond electronics. In this context, the applicants' recent discovery of the highly novel steady state deep-depletion concept for diamond devices opens routes for further advancements in the field of diamond power devices; critically, deep-depletion devices remove the need for an n-type doping. Vertical Deep-Depletion (D2) Diamond MOSFETs and Trench MOS Schottky barrier diodes (TMBS) will be realised offering exceptional performance in terms of power handling capability, size, switching frequency and thermal-radiation resilience. Developing more energy-efficient high-power devices will lead to efficient power converters, key for the drive to more efficient power generation and distribution systems within the context of the low carbon economy. However, additionally, diamond devices proposed will be that these devices can tolerate extreme operational environments and offer enormous potential in key sectors such as automotive, aerospace, and nuclear industrial sectors.

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.

Development of materials has underpinned human and societal development for millennia, and such development has accelerated as time has passed. From the discovery of bronze through to wrought iron and then steel and polymers the visible world around has been shaped and built, relying on the intrinsic properties of these materials. In the 20th century a new materials revolution took place leading to the development of materials that are designed for their electronic (e.g. silicon), optical (e.g. glass fibres) or magnetic (e.g. recording media) properties. These materials changed the way we interact with the world and each other through the development of microelectronics (computers), the world wide web (optical fibre communications) and associated technologies. Now, two decades into the 21st century, we need to add more functionality into materials at ever smaller length-scales in order to develop ever more capable technologies with increased energy efficiency and at an acceptable manufacturing cost. In pursuing this ambition, we now find ourselves at the limit of current materials-processing technologies with an often complex interdependence of materials properties (e.g. thermal and electronic). As we approach length scales below 100s of nanometres, we have to harness quantum effects to address the need for devices with a step-change in performance and energy-efficiency, and ultimately for some cases the fundamental limitations of quantum mechanics. In this programme grant we will develop a new approach to delivering material functionalisation based on Nanoscale Advanced Materials Engineering (NAME). This approach will enable the modification of materials through the addition (doping) of single atoms through to many trillions with extreme accuracy (~20 nanometres, less than 1000th the thickness of a human hair). This will allow us to functionalise specifically a material in a highly localised location leaving the remaining material available for modification. For the first time this will offer a new approach to addressing the limitations faced by existing approaches in technology development at these small length scales. We will be able to change independently a material's electronic and thermal properties on the nanoscale, and use the precise doping to deliver enhanced optical functionality in engineered materials. Ambitiously, we aim to use NAME to control material properties which have to date proven difficult to exploit fully (e.g. quantum mechanical spin), and to control states of systems predicted but not yet directly experimentally observed or controlled (e.g. topological surface states). Ultimately, we may provide a viable route to the development of quantum bits (qubits) in materials which are a pre-requisite for the realisation of a quantum computer. Such a technology, albeit long term, is predicted to be the next great technological revolution NAME is a collaborative programme between internationally leading UK researchers from the Universities of Manchester, Leeds and Imperial College London, who together lead the Henry Royce Institute research theme identified as 'Atoms to Devices'. Together they have already established the required substantial infrastructure and state-of-the-art facilities through investment from Royce, the EPSRC and each University partner. The programme grant will provide the resource to assemble the wider team required to deliver the NAME vision, including UK academics, research fellows, and postdoctoral researchers, supported by PhD students funded by the Universities. The programme grant also has significant support from wider academia and industry based both within the UK and internationally.

The rapid growth of the rich variety of connected devices, from sensors, to cars, to wearables, to smart buildings, is placing a varied and highly complex set of bandwidth, latency, priority, reliability, power, roaming, and cost requirements on how these devices connect and on how information is moved around. Efficient communications remains a very difficult challenge for our digital world, and understanding how to design devices and systems that make good trade-offs between these different requirements requires skills from several disciplines. MANGI will underpin the critical mass and expertise in Bristol's Smart Internet and Devices Laboratory (SIDL) enabling the creation of a Next Generation Internet, with career development of our senior and most talented postdoctoral researchers forming a core part of our activity. Bristol's SIDL brings together the Smart Internet Lab (SIL) in Electrical & Electronic Engineering and the Centre for Device Thermography and Reliability (CDTR) in Physics at the University of Bristol, and has a world-leading track record, spanning the complete digital communication engine from novel wide bandgap semiconductor RF/optical devices to state-of-the-art high performance network architecture design and operation, on the pathway to enabling the Next Generation Internet. New devices and materials are critically needed as key enablers for the necessary transition from the current to the Next Generation Internet which needs to be energy efficient and provide highly flexible connectivity across optical-wireless domains. Using pump-priming projects to retain and develop our outstanding postdoctoral researchers, revolutionary interdisciplinary approaches will be developed in order to adopt high risk strategies focused on grand challenges aimed at enabling the Next Generation Internet. This approach taken is not possible with standard mode funding. Advances in component technologies, to provide higher speed/linearity, higher power devices, more compact device and packaging design, alongside use of new materials will have transformative impact upon network operation. The flexibility of the platform will be a corner stone of MANGI, allowing our most senior postdoctoral researchers to develop and drive their own research ideas, with interdisciplinary mentoring by senior members of SIDL and industry. This will help remove blockages in current technology and overcome the current internet infrastructure challenges. Standard research paths are not able to support independent development and innovation at physical and network layer functionalities, protocols, and services, while at the same time supporting the increasing bandwidth demands of changing and diverse applications, largely because of current limitations in semiconductor device and packaging technology and a lack of co-design of the multitude of constituent parts.