Charge transport in doped zigzag phosphorene nanoribbons

Abstract

The effects of lattice distortion and chemical disorder on charge transport properties of twoterminal zigzag phosphorene nanoribbons (zPNRs), which shows resonant tunneling behavior under an electrical applied bias, are studied. Our comprehensive study is based on ab initio quantum transport calculations on the basis of the Landauer theory. We use nitrogen and silicon substitutional dopant atoms, and employ different physical quantities such as the I − V curve, voltage drop behavior, transmission spectrum, transmission pathway, and atomic current to explore the transport mechanism of zPNR devices under a bias voltage. The calculated transmission pathways show the transition from a ballistic transport regime to a diffusive and in some particular cases to localized transport regimes. Current flowing via the chemical bonds and hopping are monitored, however, the conductance originates mainly from the charge traveling through the chemical bonds in the vicinity of the zigzag edges. Our results show that, in the doped systems, the device conductance decreases and the negative differential resistance characteristic becomes weak or is eliminated. Besides, the conductance in a pure zPNR system is almost independent of the ribbon width.PACS numbers:

Phosphorene as a nanoelectromechanical material

“…9 illustrates, they move through the chemical bonds from the top on the left to the bottom on the right. This figure is comparable with the calculated transmission pathways in zz phosphorene nanoribbons where the charge carriers pass through the chemical bonds in the vicinity of the zz edges [42]. The conductance of the system displayed in the lower panel of Fig.…”

“…By shifting up and down the discrete and narrow density of states of the left and right electrodes, the bias voltage could provide the conditions that transmission reduces under bias enhancement, leading to the resonant tunneling transport and observed NDR behavior [40,42]. The peak-to-valley ratio (PVR), which is defined as the ratio of the current at the resonant tunneling peak energy to that at the valley, is obtained around 2.5 -3.8, which is comparable to the reported values of 7-25 in the zz phosphorene nanoribbons (zPNRs), or 5.5 in the z-MoS 2 NRs [42], but very small in comparison with the observed PVR value in CdSe quantum dots (∼ 1000), or a PVR value of 50 − 200 in defected aGNRs [42]. The PVR quantity is a measure of the strength of NDR characteristic.…”

“…The transmission pathway [31,37,42] is extracted from the splitting of the transmission coefficients into the bond directions and shows how carriers move through the system. The transmission pathway illustrated in Fig.…”

Electronic Transport in the V-Shaped Edge Distorted Zigzag Graphene Nanoribbons with Substitutional Doping

“…Using the optimized structures, we construct device geometries, which consist of three regions: left electrode, central scattering region, and right electrode. Each electrode consists of 3 unit cells with a length of 7.38Å and the length of the scattering region in each device is 24.61Å [19]. The electrodes are modeled as an electron gas with a fixed chemical potential.…”

Ambipolar transport compact models for two-dimensional materials based field-effect transistors

“…Ambipolar Two-Dimensional materials based Field-Effect Transistors (2D-FETs), such as Black Phosphorus [1][2][3][4][5][6][7][8][9] (BP), molybdenum diselenide [10] (MoSe 2 ), and tungsten diselenide [11,12] (WSe 2 ), have been reported so far. Because of their ambipolar characteristics, 2D-FETs are expected to achieve p-FET and n-FET in the same device, and thus enable various innovative applications, including ambipolar flash memories, artificial synaptic transistors [13] , logic devices, and light-emitting transistors [14] .…”