Electron transport through nanoscale multilayer graphene and hexagonal boron nitride junctions

In this study, we employ the non-equilibrium Green's function (NEGF) method combined with density functional theory (DFT) to compare electron transport through several layers of nanoscale graphene and hexagonal boron nitride (h-BN). Calculations were performed for one to six layers, corresponding to thicknesses of 0.5-3.0 nm, respectively. Electron transport was computed perpendicular to the layers in the stacking direction. We compared the decay of the current with the number of layers and evaluated the ability of h-BN to filter currents as a material coating. To investigate the effect of disorder, we included two major defects in the graphene lattice, namely, nitrogen doping and Stone-Wales defects. Nitrogen doping transforms graphene from a zero-bandgap semiconductor to a metal, while Stone-Wales defects open the bandgap. For h-BN, we considered Stone-Wales defects. A detailed comparison of electron transport through five materials, that is, multilayer nanoscale graphene, N-doped multilayer nanoscale graphene, Stone-Wales-defective multilayer nanoscale graphene, h-BN, and Stone-Wales-defective h-BN allowed us to understand the currents at the nanoscale and the chemical and structural control over the electron transport. The slopes of the current decay with thickness enabled us to extrapolate trends for electron transport in thicker multilayer carbon and h-BN materials.