Modelling conduction in carbon nanotube networks with different thickness, chemical treatment and irradiation
Modelling conduction in carbon nanotube networks with different thickness, chemical treatment and irradiation
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DOI：
10.1016/j.physe.2007.10.038
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发表时间：
2008-05-01
影响因子：
3.3
通讯作者：
Roth, S.
中科院分区：
文献类型：
--
作者：
Kaiser, A. B.;Skakalova, V.;Roth, S.
我们展示了如何单壁碳纳米管（SWNT）网络的电子输运性质的主要特点可以理解的一个简单的模型，涉及金属导电中断薄隧道势垒，背散射区边界声子，和可变范围跳跃。在这个框架内，我们研究的影响，减少厚度的单壁碳纳米管网络，化学处理，和离子辐照。传导机制可以从局域态之间的可变范围跳跃（对于最薄的网络）调谐到由薄势垒中断的金属传导，通过薄势垒的传导是通过隧穿（对于厚的独立膜）。用不同的分子对厚膜进行化学处理，可以保留金属特性，但改变（增加或减少）载流子密度。对于离子辐照的厚膜，我们发现两个相互竞争的影响：在直接影响层，降低电导率，和退火效应延伸比离子渗透深度，增加电导率，并导致峰值的电导率作为辐照剂量的函数的跳跃型导电的变化。我们简要地讨论了电流-电压特性和可能的Luttinger液体效应。(C)2007 Elsevier B. V.保留所有权利。
We show how the main features of the electronic transport properties of single-wall carbon nanotube (SWNT) networks can be understood in terms of a simple model involving metallic conduction interrupted by thin tunnelling barriers, backscattering by zone-boundary phonons, and variable range hopping. Within this framework we examine the effect of reducing the thickness of the SWNT networks, chemical treatments, and ion irradiation. The conduction mechanism can be tuned from variable-range hopping between localized states (for the thinnest networks), to metallic conduction interrupted by thin barriers through which conduction is by tunnelling (for thick freestanding films). Chemical treatment of the thick films by different molecules leads to retention of metallic character but changes (increases or decreases) the charge carrier density. For ion-irradiated thick films we find two competing effects: a change to hopping-type conduction in the direct impact layer that lowers conductivity, and annealing effects extending deeper than the ion penetration depth that increase conductivity and lead to a peak in conductivity as a function of irradiation dose. We briefly discuss current-voltage characteristics and possible Luttinger liquid effects. (C) 2007 Elsevier B.V. All rights reserved.