High-bias negative differential resistance effect in pure, doped and co-doped carbon nanotubes connected to boron nitride nanotubes

Abstract

The electronic and transport properties of various devices made of carbon nanotube (CNT), B, Al, N-doped and BN, AlN co-doped carbon nanotubes sandwiched between boron nitride nanotube (BNNT) electrodes were investigated using combined density functional theoretical and the non-equilibrium Green's function (DFT-NEGF) methods. The undoped, doped and co-doped CNTs exhibit low band gap which make them suitable for semiconductor devices. The transport properties such as transmission spectrum, density of states (DOS) and current-voltage characteristic of all the devices were determined. A negative differential resistance (NDR) is observed for undoped, doped and co-doped CNTs at high bias (±1 to ±3 V). It is revealed that the NDR region as well as the peak-to-valley ratio of CNT can be tuned by doping B, N, Al, BN and AlN. The rectification ratio of CNT varies with the type of dopant atoms. The NDR effect in the current-voltage curve along with high rectification ratio proffer the potential applications of doped and co-doped CNTs in nano-rectifiers.