Achieved negative differential resistance behavior of Si/B-substituted into a C6 chain sandwiched between capped carbon nanotube junctions.

Najmeh Janatipour,Georg Schreckenbach,Siamak Noorizadeh,Zabiollah Mahdavifar

doi:10.1039/d1ra08810f

Najmeh Janatipour, Georg Schreckenbach + Show 2 more

Open Access

https://doi.org/10.1039/d1ra08810f

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Abstract

Electronic transport properties of a pristine C6 chain and Si/B-substituted into the C6 chain sandwiched between two (5, 5) capped carbon nanotube electrodes were investigated through first-principles calculations based on non-equilibrium Green's functions (NEGF) conjugated with density functional theory (DFT). Si and B substitutions will affect the I–V curve of a pristine C6 chain. In the I–V characteristics, multi negative differential resistance (NDR) with large peak to valley ratio (PVR) and rectifying actions were observed. The NDR behavior originates from the joining and moving of conduction orbitals inside and outside of the bias window at a certain bias voltage. Furthermore, the assessment of transmission coefficient and distribution of molecular orbitals reveals that the rectifying performance is the result of the asymmetric distribution of the frontier molecular orbitals in the central region and their coupling with the electrodes. Multi NDR behavior of B substitution under very low bias voltage is a unique property of our proposed devices. Moreover, the CNT|C–(B–C)2–C|CNT molecular device shows a high PVR up to 31.8, which demonstrates that the proposed devices can be useful for molecular switching in nanoelectronic devices.

Highlights

The main idea of molecular electronics is to replace the traditional semiconductor-based components with single molecules to make nanoelectronic devices that are much smaller than those that existed in the past
Our proposed devices show a high peak to valley ratio (PVR) up to 31.8 for the B dopant. These results demonstrate that our proposed devices are useful for molecular switching, diodes, logic, multipliers, high-frequency oscillators and other practical applications
First-principles calculations based on density functional theory (DFT) conjugated with non-equilibrium Green's functions (NEGF)[42] implemented in the TranSIESTA42,43 package were performed to evaluate the electronic structures and electronic transport properties of CNTjC6jCNT, CNTjC–(Si–C)2–CjCNT and CNTjC–(B–C)2–CjCNT molecular devices

Summary

Introduction

The electronic properties of atomic carbon nanowires sandwiched between metal and carbon based electrodes were predicted theoretically.[8,9,14,18] Khoo et al.[18] reported the even– odd behavior and negative differential resistance (NDR) characteristic of linear atomic chains with 3, 4, 5, and 6 carbon atoms connected between two (5,5) capped CNT electrodes. Liew et al.[9] investigated the electronic transport properties of different lengths of carbon atomic chains covalently connecting to a (5, 5) capped CNT and (3, 0) graphene nanoribbon as le and right electrodes, respectively. They realized that the rectifying performance was dependent on asymmetric distortion and movement of resonance while it is reduced when the chain states approach to the Fermi level. It should be pointed out that a 1D boron carbide (BC) nanowire has been synthesized experimentally and several methods are available to produce different morphological structures of BC chains.[39,40,41] Our proposed molecular devices display NDR behavior with large peak-to-valley ratio and obvious rectifying performance. These results demonstrate that our proposed devices are useful for molecular switching, diodes, logic, multipliers, high-frequency oscillators and other practical applications

Models and methods

Results and discussion

Conclusion