Graphene-based biosensor using transport properties

The potential of graphene nanoribbons (GNR's) as molecular-scale sensors is investigated by calculating the electronic properties of the ribbon and the organic molecule ensemble. The organic molecule is assumed to be absorbed at the edge of a zigzag GNR. These nanostructures are described using a single-band tight-binding Hamiltonian. Their transport spectrum and density of states are calculated using the nonequilibrium Green's function formalism. The results show a significant suppression of the density of states (DOS), with a distinct response for the molecule. This may be promising for the prospect of GNR-based single-molecule sensors that might depend on the DOS (e. g., devices that respond to changes in either conductance or electroluminescence). Further, we have investigated the effect of doping on the transport properties of the system. The substitutional boron and nitrogen atoms are located at the center and edge of GNR's. These dopant elements have significant influence on the transport characteristics of the system, particularly doping at the GNR edge.