As IBM's 2nm chip is pushing Moore's law approaching its limit, conventional computing techniques are struggling to offer high performance computing within power consumption constraints. Inspired by the fault tolerance capability of the human brain, approximate computing, which is error tolerant, can offer a huge reduction in computer power consumption without affecting the results (such as accuracy) of certain human perception and recognition related computation that only require a result to be approximate, rather than accurate. Examples include Artificial Intelligence (AI), Deep Learning (DL), image processing and even some cryptographic schemes. However, approximate computing has been shown to have security vulnerabilities due to the unpredictability of intrinsic errors that may be indistinguishable from malicious modifications. Due to the inherent power and area savings achieved by approximate computing, security countermeasures shold also be lightweight ande efficient. Hence, the aim of this proposal is to use advanced hardware security techniques to enable the development of approximate computing technologies that have both optimal security protection and optimal system efficiency. Currently, no comprehensive research has been conducted to date into security of approximate computing or into countermeasures that protect such designs. Physical unclonable function (PUF), as a lightweight hardware security primitive, is one of the best candidates for securing resource-constrained applications, such as approximate computing. A PUF can be used to generate a unique digital fingerprint for an electronic device based on manufacturing process variations of silicon chips. Currently, PUFs have been widely studied for conventional computing but no effective intrinsic PUF designs using approximate techniques have been presented. This project is timely because approximate computing has rapidly attracted attention from both academica and industry, as it addresses one of the fundamental barriers in computing systems, power dissipation, but it has also opened new vectors of attacks. This project will develop an intrinsic PUF design based on the normal operations of an approximate processor without the need for addtional hardware resource. The project will aslo address for the first time how to achieve secure and effective approximate computing designs. Thales UK, a leader in designing and building mission-critical information systems for the defence, security, aerospace, and transportation sections, has already invited the PI to join the Thales CyRes-Advance project to investigate security protection for connected and autonomous vechicles (CAVs) by considering hardware security. Thales will provide £250k in-kind support, such as technical advice/review of the hardware design, access to Thales CAV test platform and experimental validation for the project, to accelerate the research process and produce high-quality research outputs.

Nanoscale resistive switching (RS) elements, also known as memristors, are nowadays regarded as a promising solution for establishing next-generation memory, due to their infinitesimal dimensions, their capacity to store multiple bits of information per element and the miniscule energy required to write distinct states. Currently, the microelectronics community aspires exploiting these attributes in a deterministic fashion where information encoding and processing is realised via static representations. In consequence, research efforts are focused on optimising memristor technology in a "More Moore" approach to comply with existing CMOS devices attributes, i.e. high-yield, supreme reproducibility, very long retention characteristics and conventional circuit design formalisms. The functional properties of such elements are however associated with irreversible rate-limiting electro/thermo-dynamic changes that often bring them in "far from equilibrium" conditions, manifesting opportunities for unconventional computing within a probabilistic framework. This fellowship aims exploiting the strong emergence of ultra-thin functional oxides, nanoscale resistive switching elements and large-scale systems of the same. We will first investigate the effect of quantum phase transitions and the mechanisms leading into thermodynamically stable/unstable long-range order/disorder of distinct materials. These mechanisms will then be exploited in nanoscale solid-state devices for establishing the state-of-the-art in non-volatile multi-state memory but also volatile elements that could potentially be employed as dynamic computational elements. The rich-dynamics of the later will be compared against reaction-diffusion mechanisms of naturally occurring nano-systems to facilitate novel design paradigms and emerging ICT applications for substantiating unconventional computation formalisms. A successful outcome will demonstrate a mature memristive device manufacturing technology that will be supported by the necessary design tools, for taking CMOS technology far beyond its current state-of-art.

Graphene is a single layer of graphite just one atom thick. As a material it is completely new - not only the thinnest ever but also the strongest. It is almost completely transparent, yet as a conductor of electricity it performs as well or even better than copper. Since the 2010 Nobel Prize for Physics was awarded to UK researchers in this field, fundamental graphene research has attracted much investment by industry and governments around the world, and has created unprecedented excitement. There have been numerous proof-of concept demonstrations for a wide range of applications for graphene. Many applications require high quality material, however, most high quality graphene to date is made by exfoliation with scotch tape from graphite flakes. This is not a manufacturable route as graphene produced this way is prohibitively expensive, equivalent to £10bn per 12" wafer. For high quality graphene to become commercially viable, its price needs to be reduced to £30-100 per wafer, a factor of 100 million. Hence graphene production and process technology is the key bottleneck to be overcome in order to unlock its huge application potential. Overcoming this bottleneck lies at the heart of this proposal. Our proposal aims to develop the potential of graphene into a robust and disruptive technology. We will use a growth method called chemical vapour deposition (CVD) as the key enabler, and address the key questions of industrial materials development. CVD was the growth method that opened up diamond, carbon nanotubes and GaN to industrial scale production. Here it will be developed for graphene as CVD has the potential to give graphene over large areas at low cost and at a quality that equals that of the best exfoliated flakes. CVD is also a quite versatile process that enables novel strategies to integrate graphene with other materials into device architectures. In collaboration with leading industrial partners Aixtron UK, Philips, Intel, Thales and Selex Galileo, we will develop novel integration routes for a diverse set of near-term as well as future applications, for which graphene can outperform current materials and allows the use of previously impossible device form factors and functionality. We will integrate graphene for instance as a transparent conductor into organic light emitting diodes that offer new, efficient and environmentally friendly solutions for general lighting, including a flexible form factor that could revolutionize traditional lighting designs. We will also integrate graphene into liquid crystal devices that offer ultra high resolution and novel optical storage systems. Unlike currently used materials, graphene is also transparent in the infrared range, which is of great interest for many sensing applications in avionics, military imaging and fire safety which we will explore. Furthermore, we propose to develop a carbon based interconnect technology to overcome the limitations Cu poses for next generation microelectronics. This is a key milestone in the semiconductor industry roadmap. As a potential disruptive future technology, we propose to integrate graphene into so called lab-on-a-chip devices tailored to rapid single-molecule biosensing. These are predicted to revolutionize clinical analysis in particular regarding DNA and protein structure determination.

The ever-increasing combined carbon footprint of information and communications technology (ICT) is unsustainable - more efficient devices must be developed. Thermal characterisation, which feeds into design optimisation, is one of the key steps for ensuring the efficiency and reliable operation of the new electronic devices being developed. However, accurately measuring the temperature of leading-edge electronic devices is becoming increasingly difficult or impossible because of their small size, and that is the challenge addressed in this proposal. Wide bandgap electronic devices including GaN have great proven potential for the next generation of sustainable ICT and power electronics, contributing to the needed carbon emissions reduction. Miniaturization is one of the routes to further increase the efficiency and performance of wide bandgap electronic devices, decreasing the active region size to <200 nm, similar to the technology pathway that silicon (Si) electronics has taken, using concepts such as the FinFET. Thermal management, which is the efficient extraction of waste heat from the active part of the device, is especially important for achieving efficient reliable nanoscale electronic devices; thermal resistance increases as they are "scaled" to nanometre dimensions because of a thermal conductivity reduction and heat confinement in 3-D device structures, e.g. in a fin shape. While self-heating can be mitigated reasonably easily for lower power density Si FinFETs, it is potentially a significant roadblock for "scaled" wide bandgap devices which operate at enormous power densities. However there is currently no thermal imaging technique with a sufficiently high spatial resolution (e.g. Raman thermography has a diffraction limited resolution of about 0.5 micrometer, >10x the hotspot size) to be able to accurately measure the hotspot temperature of these novel nanoscale wide bandgap electronic devices. Instead we currently rely on complex electrothermal models to estimate the temperature of nanoscale devices, with inherent uncertainties - measurement is needed. A step change is required, namely a sub diffraction limit (super resolution) thermal imaging technique, which is addressed by the Future thermal Imaging with Nanometre Enhanced Resolution (FINER) project. We will develop a transformative nano quantum dot based thermal imaging (nQTI) technique to deliver nanometre resolution thermal imaging for the first time. To demonstrate the newly developed technique our application focus is on scaled wide bandgap electronic devices supplied by our national and international partners, however this technique will be widely applicable. Quantum dots are ideal for this application: They can be deposited as a nm-thickness film on the surface of the device being tested, and the emission colour is temperature dependent, which is what we exploit for thermal imaging. Structured Illumination Microscopy (SIM) and Stimulated Emission Depletion (STED) super-resolution techniques which were originally developed for fluorescence microscopy, but are presently unsuitable for thermal imaging, will be exploited to achieve a resolution as small as 50nm for nQTI. nQTI will enable nano-scale electrothermal models to be developed and experimentally verified. Accurate models will further our understanding of nano-scale self-heating and heat diffusion, feeding back into improved device designs and novel thermal management solutions. This work will be done at the Centre for Device Thermography and Reliability (CDTR) which has an international reputation for being at the forefront of high spatial and temporal resolution thermal imaging, pioneering Raman thermography. This expertise makes the CDTR ideally placed to deliver this project successfully. The generous industrial support for this programme demonstrates that there is a great need for this and their belief in our ability to successfully deliver it.

Technologies underpin economic and industrial advances and improvements in healthcare, education and societal and public infrastructure. Technologies of the future depend on scientific breakthroughs of the past and present, including new knowledge bases, ideas, and concepts. The proposed international network of interdisciplinary centre-to-centre collaborations aims to drive scientific and technological progress by advancing and developing a new science platform for emerging technology - the optical frequency comb (OFC) with a range of practical applications of high industrial and societal importance in telecommunications, metrology, healthcare, environmental applications, bio-medicine, food industry and agri-tech and many other applications. The optical frequency comb is a breakthrough photonic technology that has already revolutionised a range of scientific and industrial fields. In the family of OFC technologies, dual-comb spectroscopy plays a unique role as the most advanced platform combining the strengths of conventional spectroscopy and laser spectroscopy. Measurement techniques relying on multi-comb, mostly dual-comb and very recently tri-combs, offer the promise of exquisite accuracy and speed. The large majority of initial laboratory results originate from cavity-based approaches either using bulky powerful Ti:Sapphire lasers, or ultra-compact micro-resonators. While these technologies have many advantages, they also feature certain drawbacks for some applications. They require complex electronic active stabilisation schemes to phase-lock the different single-combs together, and the characteristics of the multi-comb source are not tuneable since they are severely dictated by the opto-geometrical parameters of the cavity. Thus, their repetition rates cannot be optimised to the decay rates of targeted samples, nor their relative repetition rates to sample the response of the medium. Such lack of versatility leads to speed and resolution limitations. These major constraints impact the development of these promising systems and make difficult their deployment outside the labs. To drive OFC sources, and in particular, multi-comb source towards a tangible science-to-technology breakthrough, the current state of the art shows that a fundamental paradigm shift is required to achieve the needs of robustness, performance and versatility in repetition rates and/or comb optical characteristics as dictated by the diversity of applications. In this project we propose and explore new approaches to create flexible and tunable comb sources, based on original design concepts. The novelty and transformative nature of our programme is in addressing engineering challenges and designs treating nonlinearity as an inherent part of the engineering systems rather than as a foe. Using the unique opportunity provided by the EPSRC international research collaboration programme, this project will bring together a critical mass of academic and industrial partners with complimentary expertise ranging from nonlinear mathematics to industrial engineering to develop new concepts and ideas underpinning emerging and future OFC technologies. The project will enhance UK capabilities in key strategic areas including optical communications, laser technology, metrology, and sensing, including the mid-IR spectral region, highly important for healthcare and environment applications, food, agri-tech and bio-medical applications. Such a wide-ranging and transformative project requires collaborative efforts of academic and industrial groups with complimentary expertise across these fields. There are currently no other UK projects addressing similar research challenges. Therefore, we believe that this project will make an important contribution to UK standing in this field of high scientific and industrial importance.