Collaborative Research: Structure and Morphology of Graphene Sheets for Carbon-Based Nanoelectronics

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Graphene, a single-layer of carbon atoms, exhibits dissipation-free electric conduction over the scale of microns even at room temperature. As such, graphene could enable the continuation of the miniaturization trend in nanoelectronics at a time when silicon-based devices reach their natural limitations. However, the control over the area and quality of graphene sheets remains a major challenge because their morphology is determined both by atomic-scale phenomena and by long-ranged elastic interactions of surface features. Experiments on graphene growth on silicon carbide show that the key to grow large and smooth graphene sheets lies in controlling the structure of the precursor layer, i.e. of the interface between graphene and the substrate. To achieve our primary objective of controlling the quality of graphene sheets, we propose a multi-scale approach that combines experimental techniques for surface characterization with atomic-scale calculations, genetic algorithms for finding the surface structure, and continuum models of nucleation and growth.If successful, this work will guide novel approaches to grow large and smooth graphene sheets, which through lithographic patterning can be used to fabricate low-power nanoelectronic devices. Our investigations of the structure and the defects of the precursor layer will provide insights into the carrier scattering mechanisms and hence into the performance of graphene-based devices. Furthermore, we will identify reconstructions of the precursor layer that are particularly suitable as templates for the assembly of regular arrays of nanostructures such as fullerenes, metallic clusters, and functional molecules. Aspects of this work will be presented in recently developed courses at Colorado School of Mines and Brown University. The investigators will be actively involved in career advising and student mentorship, and will use the results of this research to enhance the experiences of K-12 mathematics teachers and high-school students under the outreach program of the Materials Research Science and Engineering Center at Brown.