Electron percolation in realistic models of carbon nanotube networks

Abstract

The influence of penetrable and curved carbon nanotubes (CNT) on the charge percolation in threedimensional disordered CNT networks have been studied with Monte-Carlo simulations. By considering carbon nanotubes as solid objects but where the overlap between their electron cloud can be controlled, we observed that the structural characteristics of networks containing lower aspect ratio CNT are highly sensitive to the degree of penetration between crossed nanotubes. Following our efficient strategy to displace CNT to different positions to create more realistic statistical models, we conclude that the connectivity between objects increases with the hard-core/ soft-shell radii ratio. In contrast, the presence of curved CNT in the random networks leads to an increasing percolation threshold and to a decreasing electrical conductivity at saturation. The waviness of CNT decreases the effective distance between the nanotube extremities, hence reducing their connectivity and degrading their electrical properties. We present the results of our simulation in terms of thickness of the CNT network from which simple structural parameters such as the volume fraction or the carbon nanotube density can be accurately evaluated with our more realistic models. V

Effective resistance of random percolating networks of stick nanowires: Functional dependence on elementary physical parameters

“…Simoneau and al. studied numerically the influence on the estimated effective resistance of the statistical distribution chosen for angles, lengths, diameters of nanowires (in that case CNTs) 11 , waviness, degree of penetration of CNTs 12 , under the junction dominated assumption (JDA) -i.e. assuming ballistic transport in individual CNTs.…”

“…penetration of CNTs 12 , under the junction dominated assumption (JDA) -i.e. assuming ballistic transport in individual CNTs.…”

Refractory Vertically Aligned Carbon Nanotube–Boron Nitride Nanocomposites for Scalable Electrical Anisotropic Interconnects

“…It was reported that for randomly aligned CNTs, measuring direction does not affect conductivity by too much. 20 For the bare VACNTs, multiple contact points actually existed among adjacent tubes. Thus, a complex and nondirectional conducting network formed, on which condition the conduction behavior of the electron was dominated not only by the pathways provided by individual VA CNTs but also by the intertube percolation.…”

Effect of Junction Resistance on the Percolation Resistivity of Metal Nanowire Networks

“…At those thicknesses, the electrical transport and resistivity in these networks deviate from their bulk properties and are governed by percolation theory (Stauffer and Aharony, 1985). As a result, Monte Carlo simulations need to be employed to theoretically calculate the percolation resistivity of networks consisting of 1D nanoelements (Jagota and Tansu, 2015;Simoneau et al, 2015;White et al, 2009;Berhan and Sastry, 2007). However, most simulation work on 1D nanoelement networks has modeled the nanowires as straight sticks.…”

“…Curviness not only affects the percolation threshold, but also the resistivity of the network, which determines the sheet resistance of transparent conductors. In a few previous studies, it has been shown that waviness decreases the conductivity of carbon nanotube networks (Simoneau et al, 2015) and three-dimensional (3D) carbon nanotube-based nanocomposites (Bao et al, 2013;Takeda et al, 2011;Li et al, 2007;Dalmas et al, 2006). However, a systematic and comprehensive study of the effect of nanowire curviness on the scaling of percolation resistivity in metal nanowire networks and its interaction with other nanowire/device parameters, in particular nanowire alignment, is currently lacking.…”