We report a comparative study and Raman characterization of the formation of graphene on single crystal Ni (111) and polycrystalline Ni substrates using chemical vapor deposition (CVD). Preferential formation of monolayer/ bilayer graphene on the single crystal surface is attributed to its atomically smooth surface and the absence of grain boundaries. In contrast, CVD graphene formed on polycrystalline Ni leads to a higher percentage of multilayer graphene (g3 layers), which is attributed to the presence of grain boundaries in Ni that can serve as nucleation sites for multilayer growth. Micro-Raman surface mapping reveals that the area percentages of monolayer/bilayer graphene are 91.4% for the Ni (111) substrate and 72.8% for the polycrystalline Ni substrate under comparable CVD conditions. The use of single crystal substrates for graphene growth may open ways for uniform high-quality graphene over large areas. SECTION Nanoparticles and Nanostructures

A transfer printing process that allows precise patterning of chemically converted graphene is reported. The use of a polydimethylsiloxane (PDMS) stamp and surface energy manipulation resulted in successfully transferring spin‐coated materials from one substrate to another. The method is capable of transferring sharp features to precise locations. This represents large‐scale, high‐throughput transfer printing of chemically converted graphene and paves the way for future complementary circuit design.

We have developed a dry transfer method that allows graphene to be transferred from polymerthyl-methacrylate (PMMA)/Si (silicon) substrates on commercially available hexagonal boron nitride (hBN) crystals. With this method we are able to fabricate graphene devices with little wrinkles and bubbles in graphene sheets, but that do not degrade the electronic quality more than the SiO2 substrate does. For hBN to perform the function described above substrate cleanliness is critical to get high quality graphene devices. Using hBN as a substrate, graphene exhibits enhanced mobility, reduced carrier inhomogeneity, and reduced intrinsic doping compared to graphene on SiO2 substrate.

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