Strength of graphene grain boundaries under arbitrary in-plane tension

The thermal conductivity of polycrystalline graphene is expected to be lower than that of pristine graphene, due to the existence of defects, such as grain boundaries (GBs). To study the thermal transport behavior in polycrystalline graphene, it is crucial to understand the thermal conductivity of graphene GBs as a function of the tilt GB misorientation angle and in-plane thermal loading angle. However, existing studies of thermal conductivity of graphene GBs only consider the case where the thermal flux is perpendicular or parallel to the graphene GB. To address this issue, here we perform systematic non-equilibrium molecular dynamics simulations and investigate the thermal conductivity of graphene GBs for all possible tilt GB misorientation angles (23 cases) under arbitrary in-plane thermal loading directions. The findings from the present study can offer quantitative guidance for using polycrystalline graphene in thermal devices and flexible electronics applications.

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“…. This is the second part of our previous study 48 which used the same atomic coordinates for the GBs.…”

Section: Methodsmentioning

confidence: 99%

Thermal conductivity of graphene grain boundaries along arbitrary in-plane directions: A comprehensive molecular dynamics study

Fox

Ray

2018

Journal of Applied Physics

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“…材料的各类性质存在显著影响，如石墨烯 [35] , h-BN [36] , TMDCs [37][38][39] . Shi 等人采用第一性原理模拟方法研究了包括晶界在内的点、线缺陷对单层 MoSSe 结构催化性质的影响 [21] .…”

Section: 另一方面，大量研究工作已证明表面(或边缘)和晶界等缺陷对二维纳米unclassified

Molecular dynamics simulation study on mechanical properties of Janus MoSSe monolayer

Zhang¹,

Li²,

Zhan³

et al. 2023

Acta Phys. Sin.

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This work systematically studied mechanical responses of a novel semiconducting Janus MoSSe monolayer subjected to uniaxial tensile loadings by means of molecular dynamics simulations. It is found that the Janus MoSSe monolayer shows clearly anisotropic responses along armchair and zigzag directions. The phase transition behavior was observed when the Janus MoSSe monolayer is under tension along zigzag direction at temperatures below 100 K, while it does not exist in any other conditions. The Young’s modulus, ultimate strength and ultimate strain decrease as temperature increasing. Particularly, the ductile-to-brittle fracture behavior was observed when uniaxial tension is applied along zigzag direction depending on temperatures. The underline fracture mechanism was analyzed. Moreover, mechanical properties of Janus MoSSe monolayer with various grain boundaries were also carefully explored. It is found that the ultimate strength and ultimate strain depend more sensitively for narrow grains than those wider ones. The crack is initialized near the grain boundaries and propagated along direction almost perpendicular to the grain boundaries. The findings of this work may shed some lights on design and optimization of nanoscale electronic devices based on the Janus MoSSe monolayers.

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“…The single layer CVD grown graphene was used as the contact layer, the CVD graphene has point and line defects [50]. The continuous mechanical switching with very high speed at such a defect site may eventually lead to more defects and subsequent extinction of graphene layer at the contact [51]. After the extinction of graphene at the contact, the suspended graphene directly makes contact with metal electrode.…”

Section: Various Types Of Failures In G-g Nem Contact Switchesmentioning

confidence: 99%

A Large Scale Fabrication of Graphene Based Nano-electromechanical Contact Switches With Ultra-low Pull-in Voltage

Kulothungan¹

2022

Preprint

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Nano-electromechanical (NEM) contact switches have been extensively studied to suppress the limitations of conventional complementary metal-oxide-semiconductor (CMOS) transistors. The attributes of NEM contact switches includes reduced power consumption, reduced off-state leakage current, increased on-state current and sub-thermal switching. However, unacceptably high pull-in voltage and low contact lifetime posed a significant challenge for the use of NEM contact switches in energy efficient CMOS applications. Here, we demonstrate a graphene-based electro-statically actuated NEM contact switches with ultra-low pull-in voltage and significant improvement in the contact lifetime. This was achieved by using the graphene on gold electrode as a contact material. The graphene NEM contact switches with graphene as a contact material exhibits an ultra-low pull-in voltage of < 0.5 V and high contact lifetime of more than 1.5×10 6 cycles. The switches also showed an excellent switching performance with high on/off ratio of ∼ 10 8 , an extremely low off-state current of ∼100 fA, and small hysteresis window of < 0.1 V.

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Strength of graphene grain boundaries under arbitrary in-plane tension

Cited by 31 publications

References 66 publications

Thermal conductivity of graphene grain boundaries along arbitrary in-plane directions: A comprehensive molecular dynamics study

Thermal conductivity of graphene grain boundaries along arbitrary in-plane directions: A comprehensive molecular dynamics study

Molecular dynamics simulation study on mechanical properties of Janus MoSSe monolayer

A Large Scale Fabrication of Graphene Based Nano-electromechanical Contact Switches With Ultra-low Pull-in Voltage

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