Synthesis of Semiconducting Graphene Nanoribbons via Chemical Vapor Deposition

Graphene nanoribbons (GNRs) are predicted to exhibit excellent charge and thermal transport, novel magnetic and spin-polarized edge states, and technologically useful bandgaps, provided that their edge structure and width are controlled with nearly atomic precision. However, producing GNRs with such a high degree of structural fidelity has been a major challenge. We have discovered a scalable technique to synthesize GNRs via the highly anisotropic crystal growth of graphene on Ge(001) during chemical vapor deposition. By tailoring the growth conditions, GNRs with nearly atomically-smooth armchair edges, tunable sub-10 nm widths, and lengths of hundreds of nanometers are synthesized. The GNRs are semiconducting with sizeable bandgaps and display high-performance charge transport at room temperature. By initiating growth from nanoscale seeds, arrays of GNRs with controlled placement and alignment are produced. GNRs are also grown on Si substrates by utilizing epitaxial Ge interlayers. This bottom-up method may provide a route for realizing state-of-the-art technologies based on semiconducting graphene.

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