Narrow graphene nanoribbons from carbon nanotubes

Graphene nanoribbons (GNRs) are materials with properties distinct from those of other carbon allotropes(1-5). The all-semiconducting nature of sub-10-nm GNRs could bypass the problem of the extreme chirality dependence of the metal or semiconductor nature of carbon nanotubes (CNTs) in future electronics(1,2). Currently, making GNRs using lithographic(3,4,6), chemical(7-9) or sonochemical(1) methods is challenging. It is difficult to obtain GNRs with smooth edges and controllable widths at high yields. Here we show an approach to making GNRs by unzipping multi-walled carbon nanotubes by plasma etching of nanotubes partly embedded in a polymer film. The GNRs have smooth edges and a narrow width distribution (10-20 nm). Raman spectroscopy and electrical transport measurements reveal the high quality of the GNRs. Unzipping CNTs with well-defined structures in an array will allow the production of GNRs with controlled widths, edge structures, placement and alignment in a scalable fashion for device integration.