Tuning the Electronic Properties of Atomically Precise Graphene Nanoribbons by Bottom-up Fabrication

Graphene, a monolayer of graphite, is predicted to be one of the most promising materials to replace silicon in future electronic instruments. Despite its extraordinary electronic and thermal properties, the lack of an electronic band gap severely hampers its potential for applications in digital electronics. In contrast, narrow stripes of graphene, so called graphene nanoribbons (GNRs) are semiconductors, due to the quantum confinement with the tunable band gap by variation with the width and edge structure that is armchair, zigzag or the combination of both edges. This review covers the recent progress in bottom-up approaches based on the surface-catalyzed assembly of molecular precursors and tuning of the electronic properties of GNRs by fabricating atomically precise GNRs of different widths, various edge structures as well as doped structures. In addition, this review also indicates the challenges ahead and possible promising ways to finely tune the electronic structures of GNRs through slight modifications of the molecular configurations of the precursors.