Graphene nanoribbons (often abbreviated as GNR) are planar strips of graphene with a thickness of approximately one atom. Carbon atoms in graphene are sp2-hybridized with a carbon-carbon bond length of approximately 0.142 nm. As an electronic material, graphene exhibits many desirable properties, such as high carrier mobility, a thin body and compatibility with top down fabrication.
A graphene nanoribbon can be either a zig-zag (left image) or arm-chair (right image) type. Both zig-zag and armchair type GNR are shown with varying widths. Tight-binding band structure calculation predict a zig-zag type GNR to be metallic with formation of edge states while armchair type can be either metallic or semiconducting depending on its width (chirality)