Dielectrophoretic assembly of organized carbon nanotubes and thin films

In this paper, we investigate the dielectrophoretic assembly of organized carbon nanotube (CNT) and CNT thin films. Both single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) are employed in our experiments. Electrodes with "teeth"-like patterns are fabricated to study the influence of electrode width on CNT deposition and alignment. The entire fabrication process is compatible with optical lithography based techniques. Therefore, the fabrication cost is low and the resulting devices are inexpensive. SWNT and MWNT solutions are prepared with different concentrations. The alignment of SWNT/MWNT thin films and small bundles are achieved under the optimized experimental conditions. The electrical properties of these samples are characterized. The results demonstrate that the controlled deposition of CNT thin films using dielectrophoresis is highly repeatable. The alignment of small nanotube bundles can only be achieved using narrow electrodes and low-concentration solutions. Our investigation shows that it is possible to deposit a controllable amount of CNTs in desirable locations using dielectrophoresis. This research has the potential to enable the development of practical and inexpensive CNT devices that can be used in a wide range of applications: nanoelectronics, nanobioelectronics, nanoelectromechanical systems (NEMS), and energy devices.