碳纳米管可控介电泳参数模拟研究

The Simulation Study on Controllable Dielectrophoresis Parameters of Carbon Nanotube

碳纳米管的结构以及微电极的物性参数是微纳器件制备过程中影响介电泳效率与精度的重要因素。微电极形状和电极间距与碳纳米管长度之比(λ)是两个与器件制造成本紧密相关的可控介电泳参数。本文根据有限元方法,研究了这两个参数对于介电泳力的影响规律。通过对3种电极下的碳纳米管介电泳速度进行归一化处理,结果表明碳纳米管在分散液中的介电泳速度受电极形状影响较小。而相比于电极形状,λ对介电泳力的影响更加显著。虽然电极间距越小越有利于碳纳米管的组装,但是考虑微电极加工难度与成本,认为λ在0.5~1.0为碳纳米管组装的优化区间。根据介电泳组装实验需要,给出了溶液阈值浓度修正表达式。本研究对于提高介电泳组装效率和实验精度具有一定的理论指导意义。

The structure of carbon nanotube （CNT）and physical parameters of the microelectrode exert significant influence on the efficiency and precision of dielectrophoresis （ DEP ） assembly during the process of fabricating micro-nano devices. The shape of electrodes and the ratio of the gap between two electrodes to CNT lengths（ A ）are two controllable parameters which are crucial to the cost of devices fabrication. Based on the finite element method, the influence of DEP force affected by the two parameters was investigated. The result shows the shape of electrodes exerts minor influence on the DEP velocity by normalizing the DEP velocity curves of three electrodes. Parameter A affects DEP process obviously compared with the shape of electrodes. Although decreasing the gap between two e- lectrodes is more conducive to assembly,we give the optimum interval of λ is 0.5-1.0 considering the difficulty of processing microelectrode technology and cost. In addition, the revised formula of threshold concentration was also presented in the manuscript according to the requirement of assembly experiment. The paper has a theoretical signif- icance in improving the precision and efficiency of DEP assembly.