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While numerous methods have been proposed to produce semiconducting graphene, a significant band gap has never been demonstrated. The reason is that, regardless of the theoretical gap formation mechanism, subnanometer disorder prevents the required symmetry breaking necessary to make graphene semiconducting. In this work, we show for the first time that semiconducting graphene can be made by epitaxial growth. Using improved growth methods, we show by direct band measurements that a band gap greater than 0.5 eV can be produced in the first graphene layer grown on the SiC(0001) surface. This work demonstrates that order, a property that remains lacking in other graphene systems, is key to producing electronically viable semiconducting graphene. [ABSTRACT FROM AUTHOR]

Present methods for producing semiconducting-metallic graphene networks suffer from stringent lithographic demands, process-induced disorder in the graphene, and scalability issues. Here we demonstrate a one-dimensional metallic-semiconducting-metallic junction made entirely from graphene. Our technique takes advantage of the inherent, atomically ordered, substrate-graphene interaction when graphene is grown on SiC, in this case patterned SiC steps, and does not rely on chemical functionalization or finite-size patterning. This scalable bottom-up approach allows us to produce a semiconducting graphene strip whose width is precisely defined to within a few graphene lattice constants, a level of precision beyond modern lithographic limits, and which is robust enough that there is little variation in the electronic band structure across thousands of ribbons. The semiconducting graphene has a topographically defined few-nanometre-wide region with an energy gap greater than 0.5?eV in an otherwise continuous metallic graphene sheet. [ABSTRACT FROM AUTHOR]