A First Principle Insight into Defect Assisted Contact Engineering at the Metal-Graphene and Metal-Phosphorene Interfaces

In this work we have studied bonding nature of Graphene and Phosphorene with metal (Pd) followed by carrier transport behavior and contact resistance engineering across the metal-Graphene and the metal-Phosphorene interfaces using Density Functional Theory (DFT) and Non Equilibrium Green's Function (NEGF) computational methods. We have studied, how carrier transports at the interfaces is limited by van der Waals (vdW) gap across the interfaces and how the gap can be reduced by creating the Carbon vacancy (defect engineering) at the Graphene-Palladium interface. We have seen that the defect engineering enhances the Carbon-Palladium bond at the interface which reduces the van der Walls (vdW) gap, hence contact resistance due to corresponding reduction in the tunneling barrier width at the interface. We have also studied that the defect engineering (Phosphorous vacancy) at the Phosphorene-Palladium interface is not effective as Graphene-Palladium interface because it has less interfacial (vdW) gap than Graphene-Palladium interface intrinsically.