Graphene nanoribbons with wings

Abstract

We have investigated electronic transport in graphene nanoribbon devices with additional bar-shaped extensions ("wings") at each side of the device. We find that the Coulomb-blockade dominated transport found in conventional ribbons is strongly modified by the presence of the extensions. States localized far away from the central ribbon contribute significantly to transport. We discuss these findings within the picture of multiple coupled quantum dots. Finally, we compare the experimental results with tight-binding simulations which reproduce the experiment both qualitatively and quantitatively.PACS numbers: 71.15.Mb, 81.05.ue, 72.80.Vp Graphene 1 -a monolayer of carbon atoms -possesses a variety of novel electronic properties including a linear energy dispersion relation. 2 Nanodevices made from graphene were recognized as interesting and potentially useful building blocks for applications and quantum circuits. 3,4 Narrow graphene stripes called nanoribbons 5,6 are the basic building blocks of more complicated graphene nanoelectronic devices. If they have perfect edges, they are expected to either exhibit a well defined band gap or conducting edge states depending on the edge orientation. 7