The Possibility of Chemically Inert, Graphene-Based All-Carbon Electronic Devices with 0.8 eV Gap

Graphene is an interesting electronic material. However, flat monolayer graphene does not have significant gap in the electronic density of states, required for a large on-off ratio in logic applications. We propose here a novel device architecture, composed of self-folded carbon nanotube-graphene hybrids, which have been recently observed experimentally in Joule-heated graphene. These experiments demonstrated the feasibility of cutting, folding, and welding few-layer graphene in situ to form all-carbon nanostructures with complex topologies. The electronic gap of self-folded nanotubes can be combined with the semimetallicity of graphene electrodes to form a "metal-semiconductor-metal" junction. By ab initio calculations we demonstrate large energy gaps in the transmission spectra of such junctions, which preserve the intrinsic transport characteristics of the semiconducting nanotubes despite topologically necessary disinclinations at the flat graphene-curved nanotube interface. These all-carbon devices are proposed to be constructed by contact probe cutting and high-temperature annealing and, if produced, would be chemically stable at room temperature under normal gas environments.