Abstract

Although graphene displays extraordinary electronic properties, with its massless electrons (Dirac fermions) propagating for sub-micrometer distances in a ballistic regime without scattering, the absence of an energy-gap between valence and conduction bands is a severe limitation to its applications in electronics and optoelectronics. A possible solution to this problem is to induce a band-gap opening via quantum confinement, as for the one-dimensional Carbon Nanotubes (CNTs) and Graphene Nanoribbons (GNRs). Both systems attract great interest since they maintain the outstanding transport properties of graphene with the advantage of a sizable diameter or width-dependent band-gap. While CNTs have been intensely investigated over more than 20 years, studies on GNRs are still at their early stage and only little is known about their photophysical properties. Recent works demonstrate that, in analogy with CNTs, also in GNRs the optical absorption is dominated by excitons with high binding energy [1].

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