γ-Graphyne rectifier and NDR tunable by doping, line edge roughness and twist

Abstract

The armchair γ-graphyne nanoribbon (A-γ-GyNR) based on doping boron and nitrogen atoms in left and right leads, respectively, was proposed as the initial sample of a rectifier device. Afterwards, the next five devices were presented by applying line edge roughness (LER) defect, increasing its roughness, doping concentration, and its position and twisting under six different angles to the center of the initial model. Also, the effect of width was investigated. The computational method for investigating the electronic transfer properties was a combination of the non-equilibrium Green’s function (NEGF) and the tight binding method. The current curve and transmission spectrum revealed the negative differential resistance (NDR) behavior, which underwent the most changes under the influence of LER. Density of state (DOS) peaks indicated that p-orbital had a more significant effect on transmission in all devices; on the other hand, the localization of molecular projected self-consistent Hamiltonian (MPSH) structure in positive biases resulted from the suppression of electron tunneling. Based on the findings, the maximum rectification ratio in the M″3 device, twisted by an angle of 75°, was equal to 5.86 × 108, which was 41.2 times higher than that of the initial sample; the highest NDR value of the M′1 device was 56.