First principles design of divacancy defected graphene nanoribbon based rectifying and negative differential resistance device

Soubhik Chakrabarty,Ranjit Thapa,G P Das,A H M Abdul Wasey

doi:10.1063/1.4929576

Abstract

We have studied using density functional theory and non-equilibrium Green’s function based approach, the electronic structures of 555-777 divacancy (DV) defected armchair edged graphene nanoribbons (AGNR) as well as the transport properties of AGNR based two-terminal devices constructed with one defected electrode and one N doped electrode. Introduction of 555-777 DV defect into AGNR results in shifting of the π and π∗ bands towards the higher energy value indicating a downward shift of the Fermi level. Formation of a potential barrier, analogous to that of conventional p-n junction, has been observed across the junction of defected and N-doped AGNR. The two terminal devices show diode like property with high rectifying efficiency for a wide range of bias voltages. The devices also show robust negative differential resistance with very high peak-to-valley ratio. Shift of the electrode energy states and modification of the transmission function with applied bias have been analyzed, in order to gain an insight into the nonlinear and asymmetric behavior of the current-voltage characteristics. Variation of the transport properties on the width of the ribbons has also been discussed.

Highlights

The remarkable technological progress in semiconductor device industry over the last two decades is steered by the steady trend in miniaturization of electronic components
We have studied using density functional theory and non-equilibrium Green’s function based approach, the electronic structures of 555-777 divacancy (DV) defected armchair edged graphene nanoribbons (AGNR) as well as the transport properties of AGNR based two-terminal devices constructed with one defected electrode and one N doped electrode
The reduction of structural symmetry due to the introduction of 555-777 DV defect in 8-AGNR results in electronhole asymmetry as clearly observed from the band structure and DOS shown in FIG. 2(b).The absence of electron-hole symmetry shifts the Fermi level of the defected 8-AGNR towards the lower energy value as compared with pure AGNR that gives a signature of p-type doping

Summary

Introduction

The remarkable technological progress in semiconductor device industry over the last two decades is steered by the steady trend in miniaturization of electronic components. The NDR and rectifying devices that have been reported, mostly constitute nanoribbons,[12] nanowires,[13] quantum dots,[14] nanotubes,[1,11] and molecular junctions.[15] the search is on for suitable nanostructures having tunable topology and electronic property. Graphene has attracted a lot of attention, due to its unique physical properties, high mobility, low power consumption and above all the ease to synthesize.[16,17,18,19,20] the zero band gap semi-metallic nature of graphene is not suitable for device application. (i) Armchair edged graphene nanoribbon (AGNR) and (ii) Zigzag edged graphene nanoribbon (ZGNR) Both these GNRs with each edge atom passivated by single hydrogen atom, 2158-3226/2015/5(8)/087163/11

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Conclusion