Electronic Properties of Graphene Nanoribbons With Defects

Graphene nanoribbons (GNRs) are the most important emerging Graphene structures for nanoelectronic and sensor applications. GNRs with perfect lattices have been extensively studied, but fabricated GNRs contain lattice defects the effect of which on their electronic properties has not been studied extensively enough. In this paper, we apply the Non-Equilibrium Green's function (NEGF) method combined with tight-binding Hamiltonians to investigate the effect of lattice defects on the conductance of GNRs. We specifically study, butterfly shaped GNRs, which operate effectively as switches, and have been used in CMOS-like architectures. The cases of the most usual defects, namely the single and double vacancy have been analytically examined. The effect of these vacancies was computed by placing them in different regions and with various numbers on GNR nano-devices, namely edges, main body, contacts and narrow regions. The computation results are presented in the form of energy dispersion diagrams as well as diagrams of maximum conductance as a function of the number of lattice defects. We also present results on the defect tolerance of the butterfly shaped GNR devices.