Automated process for selection of carbon nanotube by electronic property using dielectrophoretic manipulation

Abstract

This paper presents a novel and an automated selection system to separate carbon nanotubes (CNTs) by their electronic properties using a dielectrophoresis-based method. CNTs have been found as promising materials for nanoelectronics due to their sizes and unique properties. Different CNTs have different electronic properties. Conventional electronic devices that are replaced by specific CNTs can possibly provide better performance and their sizes can be reduced. However, different types of CNTs aggregate together after synthesis processes, so the resulting electronic property of bundled CNTs cannot be predicted easily. Therefore, a novel classification method is necessary to separate different electronic properties of CNTs. Since the size of CNTs is in nanoscale, traditional robotic manipulation cannot be applied. Selection and manipulation of a single CNT with a specific electronic property are challenging. AC electrokinetic assembly is one of the promising methods to manipulate a CNT in the desired position. In this paper, a dielectrophoresis-based method is used to select and manipulate different types of CNTs across microelectrodes. By combining the separation and deposition system, it enables the possibility to manipulate a single CNT precisely and repeatedly, and potentially improve the yield for fabricating CNT based devices. It can also be integrated with a traditional robotic system and implemented in current manufacturing processes. As a result, a fast and batch nano-assembly of consistent nano-devices can be achieved.

Carbon nanotube dielectrophoresis: Theory and applications

“…Notably, a switch from pDEP to nDEP for semiconducting SWNTs dispersed in alcohol medium was reported by Lai et al. [71]. Semiconducting SWNT experience pDEP in the low‐frequency range (<1 MHz) and undergo nDEP when the frequency >10 MHz.…”

“…For this review and to understand the dielectrophoretic properties of CNTs, the distinction between semiconducting and metallic CNTs is important. We consider the metallic SWNTs as conductors with conductivities in the range of 10 2 to 10 6 S/m [70,71], with very high values of the absolute permittivity [60], typically assumed to be >4000 [72]. Metallic MWNTs may also exhibit large permittivities typically in the range of 10 2 to 10 4 [73,74] and conductivities in the order of 10 2 to 10 8 S/m [75–78].…”

“…A controlled self‐alignment and assembly of suspended SWNT can be achieved through DEP resulting in reproducible, well‐defined structural arrangements of CNTs for device applications. The following section discusses the studies related to the self‐assembly, sensing, and purification reported in the past 15 years for SWNT applications, also enlisted in Table 2 [22, 60, 70, 71, 80, 160‐198].…”

“…[138] and Lai et al. [71] also reported the separation of SWNTs according to their electrical properties with a similar approach using eDEP. Selective alignment inducing separation of SWNTs was also reported by Padmaraj et al.…”

Photonic crystal with a HfO<inf>2</inf> defect to improve performance of carbon nanotube based photodetectors

“…The fabrication process began with fabricating two Au electrodes with a insulating gap of 0.5 µm on top of a quartz substrate by e-beam lithography, thermal evaporation, and liftoff. After that, a single CNT was deposited between the electrodes using the dielectrophoresis (DEP) deposition system assisted by the atomic force microscope (AFM) manipulation system [19]. A single CNT connecting to two Au electrodes is shown in Fig.…”