We have demonstrated a new method for the large-area graphene growth, which can lead to a scalable low-cost high-throughput production technology. The method is based on growing single-layer or few-layer graphene films from a molten phase. The process involves dissolving carbon inside a molten metal at a specified temperature and then allowing the dissolved carbon to nucleate and grow on top of the melt at a lower temperature. The examined metals for the metal -carbon melts included copper and nickel. For the latter, pristine single layer graphene was grown successfully. The resulting graphene layers were subjected to detailed microscopic and Raman spectroscopic characterization.The deconvolution of the Raman 2D band was used to accurately determine the number of atomic planes in the resulting graphene layers and access their quality. The results indicate that our technology can provide bulk graphite films, few-layer graphene as well as high-quality single layer graphene on metals. Our approach can also be used for producing graphene-metal thermal interface materials for thermal management applications.

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We report on the development of a new technique for the growth of graphene and graphite nanocrystals from a metal-carbon melt. The process involves dissolving carbon inside molten nickel or copper at a specified temperature and then allowing the dissolved carbon to nucleate and grow on top of the melt at a lower temperature. The morphology of graphite forming inside nickel is shown to depend on the melt composition and cooling rate. The results indicate that the graphene layers contain a wrinkled structure due to thermal expansion coefficient mismatch between the grown layers and substrate. The graphene layers, however, preserve their continuity over these wrinkles. Although the formation of wrinkles was found not to depend on the type of metal substrate, the substrate had strong effect on the quality of grown layers. The films on copper contained quite a few defects including cracks and entrapped vacancies, whereas the films grown on nickel were pristine and defects free.

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