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arXiv · 0712.1733

Frequency- and electric-field-dependent conductivity of single-walled carbon nanotube networks of varying density

Hua Xu·Liangbing Hu·Shixiong Zhang·George Gruner·Steven M. Anlage
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Abstract

We present measurements of the frequency and electric field dependent conductivity of single walled carbon nanotube(SWCNT) networks of various densities. The ac conductivity as a function of frequency is consistent with the extended pair approximation model and increases with frequency above an onset frequency $ω_0$ which varies over seven decades with a range of film thickness from sub-monolayer to 200 nm. The nonlinear electric field-dependent DC conductivity shows strong dependence on film thickness as well. Measurement of the electric field dependence of the resistance R(E) allows for the determination of a length scale $L_{E}$ possibly characterizing the distance between tube contacts, which is found to systematically decrease with increasing film thickness. The onset frequency $ω_0$ of ac conductivity and the length scale $L_{E}$ of SWCNT networks are found to be correlated, and a physically reasonable empirical formula relating them has been proposed. Such studies will help the understanding of transport properties and benefit the applications of this material system.

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Hua Xu, Liangbing Hu, Shixiong Zhang, George Gruner, Steven M. Anlage. 2008-02-22. Frequency- and electric-field-dependent conductivity of single-walled carbon nanotube networks of varying density. https://doi.org/10.1103/physrevb.77.075418

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