Transport Properties of Hybrid Biphenyl Molecular Junctions with Zigzag Graphene Nanoribbon Electrodes

In the present paper, we investigate the electronic transport properties of hybrid biphenyl molecular junctions by employing ab-initio self-consistent density functional theory (DFT) and non-equilibrium Green's functions (NEGF) technique. In the hybrid system, biphenyl molecule is bridging between different left and right electrodes via thiol (SH) and Copper (Cu) chemical groups respectively. In model A, hybrid biphenyl is connected to left and right pristine zigzag graphene nanoribbon (ZGNR) electrodes. In models B and C, hybrid biphenyl is connected to pristine ZGNR electrode in left side, while one-edge Cu-doped and both-edge Cu-doped ZGNR electrode in right side respectively. The higher current value is found for model C than that of models A and B for higher positive applied bias. Moreover, a very strong rectification effect has been revealed in models B and C. The DFT-calculated transmission characteristics further supports the observed current findings. Our results will provide a new scientific and engineering understanding to enable the rectifying performance that can be used for next generation nano-rectifier devices and other nano-electronic applications.