Tunneling resistance and its effect on the electrical conductivity of carbon nanotube nanocomposites
Tunneling resistance and its effect on the electrical conductivity of carbon nanotube nanocomposites
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DOI：
10.1063/1.4716010
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发表时间：
2012-05-01
影响因子：
3.2
通讯作者：
Weng, G. J.
中科院分区：
文献类型：
--
作者：
Bao, W. S.;Meguid, S. A.;Weng, G. J.
本文研究了电子隧穿效应对碳纳米管（CNT）聚合物纳米复合材料导电性能的影响。利用Monte Carlo模拟方法建立了碳纳米管网络的随机分布模型，并基于电子输运理论建立了碳纳米管之间的隧穿电阻。我们的工作显示了这种隧穿电阻导致的几个新特性：（i）直接接触电阻是两个相邻CNT之间的一维电子弹道隧穿的结果，（ii）纳米级CNT-CNT接触电阻应该由Landauer-Buttiker（L-B）公式表示，该公式考虑了隧穿电阻和直接接触电阻，以及（iii）单壁CNT（SWCNT）和多壁CNT（MWCNT）之间的接触电阻的差异可以通过L-B模型中的通道数来建模。模型预测表明，由于电子隧穿效应在纳米复合材料与分散的单壁碳纳米管的接触电阻起着更主导的作用比那些与多壁碳纳米管。这些结果与现有的实验数据相比，并表明，该模型可以正确地估计纳米复合材料的导电性均匀分散的碳纳米管网络。(C)2012年美国物理学会。[http：//dx.doi.org/10.1063/1.4716010]
In this paper, we examined the effect of electron tunneling upon the electrical conductivity of carbon nanotube (CNT) polymer nanocomposites. A CNT percolating network model was developed to account for the random distribution of the CNT network using Monte Carlo simulations, where the tunneling resistance between CNTs was established based on the electron transport theory. Our work shows several novel features that result from this tunneling resistance: (i) direct contact resistance is the result of one-dimensional electron ballistic tunneling between two adjacent CNTs, (ii) the nanoscale CNT-CNT contact resistance should be represented by the Landauer-Buttiker (L-B) formula, which accounts for both tunneling and direct contact resistances, and (iii) the difference in contact resistance between single-walled CNTs (SWCNTs) and multiwalled CNTs (MWCNTs) can be modeled by the channel number in the L-B model. The model predictions reveal that the contact resistance due to electron tunneling effects in nanocomposites with dispersed SWCNTs plays a more dominant role than those with MWCNTs. These results compare favorably with existing experimental data and demonstrate that the proposed model can properly estimate the electrical conductivity of nanocomposites containing homogeneously dispersed percolating CNT network. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4716010]