CRYSTALLOGRAPHY AND FUNCTIONAL EVOLUTION OF ATOMICALLY THIN CONFINED NANOWIRES

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This Established Career Fellowship proposal concerns the spatial and time resolved crystallography, structural refinement and functional evolution of one to four atom thick 1D 'Extreme Nanowires' formed inside single walled carbon nanotubes - atomically smooth templates that are thermally robust up to 1130 degrees Centigrade. This is at the practical limit of scalable fabrication, a 'Final Frontier' of materials science and the next and ultimate lowest dimension relative to two-dimensional structures such as graphene or inorganic analogues derived from metal sulphides and similar. It will address the four major aspects of atomically regulated crystal growth deemed to be the most critical in terms of their development: three-dimensional crystallography with atom-by-atom sensitivity; four-dimensional crystallography, addressing the special case of nano-Confined Phase Change Materials, which have potential utility in Non-Volatile Memory; structural refinement based on enhanced information obtained from the forgoing structural studies; and the development of thin film devices, which may be either aligned or misaligned, both for fundamental properties evaluation - including several aspects of Novel Physics - but also for 'Proof of Principle' device creation for potential exploitation in thin film devices including solar cells, chemical sensors, fuel cells, batteries and catalysts, all of which may bring economic benefits.This project is expected to play a significant role in techniques development both in Warwick and through the Project Partner network based in Oxford, Vienna, Warsaw, Pau and Beijing. The 'Ultimate Scale' physical nature of the materials under examination will both test and help improve the most sensitive characterisation methodologies currently available, especially high performance electron microscopy, associated spectroscopic methods, in situ low-temperature imaging, in situ resistance/conductivity measurements, high performance scanning probe microscopies and thin film device fabrication. This project is expected to have in particular a very significant impact on the current rapidly developing field in high-performance electron microscopy in time-resolved 4D studies in which I will exploit ultrafast imaging and diffraction capabilities available in both Oxford/Diamond and Beijing, taking advantage also of the latest developments in Direct Electron Detection in rapid and more quantitative imaging studies. In this regard, the special category of nC-PCMs will provide an ultimate test being literally the smallest scale (i.e. 1 nm) Phase Change Materials ever observed and these experiments will therefore examine reversible and irreversible phase formation at the smallest scale ever likely to be attempted. The new electron diffraction protocol that I have developed will also allow us to 'scale up' phase transformation in bundles and thin films of the template SWNTs enabling resistance and conductivity changes to be measured in situ at the same time as crystalline/glass transformations and to assess their reversibility. Any exploitable physical properties will then be assessed in simple bolometric-type devices that will be used both in further physical testing but also as exploitable 'Proof of Principle' devices.These studies will make use of the many state-of-the-art facilities available at the University of Warwick as the project requires but also more dedicated expertise and information available through a Project Partner network based in the Oxford, Vienna, Warsaw, Pau and Beijing all of whom contribute to and benefit from techniques development, reciprocal characterisation and from developing/expanding their own activities in what will be a unique World-leading enterprise lead from Warwick. The PI will lead these activities from the UK which can then potentially add 1D nanostructures to its dominance in 2D Nanomaterials by pursuing this complementary but 'Beyond Graphene' research.