Tunable rectification and negative differential resistance induced by asymmetric doping in phosphorene nanoribbon

By using first-principles calculations based on density functional theory and non-equilibrium Green's function, we present the electronic transport properties of two kinds of devices based on armchair phosphorene nanoribbons, namely, A device, and B device. In A device, the phosphorus atoms in the center of armchair phosphorene nanoribbon have been replaced by impurity atoms of the S and Si, whereas in the B device, the impurity atoms are at the edge of ribbon. The results show that the current-voltage characteristics for both devices have striking nonlinear features and the rectifying behaviors strongly depend on the positions of impurity atoms. The highest rectification ratio is obtained about 125992 at 0.8 V bias for B device. Moreover, only for A device, robust negative differential resistance is observed with a high peak-valley ratio 27500 in the bias range [-0.2, -0.6] V. The mechanism of the rectification behavior is analyzed in terms of the evolution of energy levels of the related electrodes and transmission spectra as well as the projected self-consistent Hamiltonian eigenvalues with the applied bias voltage. The results indicate that the asymmetric doping of the impurity atoms can lead to a robust rectification which can be utilized to design phosphorene-base rectifier with good performance. (C) 2018 Elsevier B.V. All rights reserved.