A first-principles study on the electronic transport properties of symmetric B/N co-doped armchair graphene nanoribbons with H/O co-saturation

Abstract

Tuning the transport properties of graphene-based devices to achieve better performance is a fascinating but tough challenge. To overcome this challenge, we created one-dimensional nanostructures that resemble chains by symmetrically doping B and N atoms at different positions in armchair graphene nanoribbons (AGNRs) of different widths saturated by H/O atoms. Their transport properties, including band structure, the spatial distribution of eigenstates, the projected density of states (PDOS), and current-voltage (I-V) curve, have been investigated depending on the non-equilibrium Green's function (NEGF) and Density functional theory (DFT) methods. Based on the calculations, the seven-atom-wide armchair graphene nanoribbons (7-AGNRs) have a distinctive negative differential resistance (NDR) effect with a maximum peak-to-valley ratio (PVR) of 3.34 × 106. We speculate that the NDR effect depends on the strength of the coupling between the band structures of the electrodes within the transmission window, and that the degree of overlap between the Pz orbitals of the doped atoms and their delocalized big π orbitals is also relevant. Compared to the existing diodes with fully hydrogenated or fluorinated edges, diodes with H/O co-saturated edges have lower start-up voltages and higher currents in the doped case, as well as rectification ratio of up to 4.48 × 106 in the range of [1.1 V, 1.4 V]. Our results have great promise for applications in digital and storage devices as well as in novel oscillators and nanoelectronics.