Analysis And Simulation Of Carbon Nanotubes' Dielectrophoresis

Since discovered in 1991, carbon nanotubes (CNTs) have attracted great research interests because of its unique one-dimensional structure and excellent properties. A large number of researches have been done both from fundamental point of view and from potentials for future applications. In the latter case, researchers have demonstrated high performance carbon nanotube based devices such as field-effect transistors, solar cells, hazard gas detector and DNA sensors. With significant advantages over their traditional counterpart, carbon nanotubes are generally believed to be the building block for next generation electronics, photonics and high performance sensors. However, the selective and controllable patterning of carbon nanotubes still remains a challenge. Recently, researchers have shown that Dielectrophoresis (DEP) is an efficient technique to manipulate carbon nanotubes. With no functionalization, DEP has the potential of separating m-SWCNT and s-SWCNT, aligning carbon nanotubes on microelectrodes, and realizing large scale manipulation. Both experimental and theoretical work are conducted, most studies focus on the frequency dependent DEP behavior of CNTs, and the translation and rotation of CNTs under electrical field. However, the mechanisms for controllable patterning of CNTs on electrodes are not fully understood.In this paper, we use electrophoresis model to analyze the space distribution of CNTs on electrodes. Various factors such as the electrode type, DEP voltage, and thermal noise are taken into consideration. Especially, the influence of already deposited CNTs on the alignment of succeeding ones is studied.