Vertical Alignment and Three-Dimensional Networks of Single-Walled Carbon Nanotubes
T.J. Lee, J. Seo, S.K. Kim, H. Lee, P.S. Weise
Hanyang University, KR
Keywords: carbon nanotube, vertical alignment, three-dimensional, networks
Abstract:Single-walled carbon nanotubes (SWCNTs) have attracted much attention because of their extraordinary properties, such as excellent mechanical strength, metal-like electrical conductivity and extreme aspect ratios. To apply such SWCNTs to a plethora of technologies, many researchers have tried to develop methods to control and to align SWCNTs. Our researches are focused on the vertical alignment of SWCNTs. The vertical alignment of SWCNTs was performed on a gold electrode by DC electrophoretic deposition and ultrasonic irradiation. Applying ultrasonic energy resulted in dramatic changes of the film morphology; the deposited SWNT bundles reassembled and oriented normal to the electrode. Oriented SWNT bundles with high density not only presented narrow size distributions, but uniformly spread on the electrode. We will also discuss the mechanism of SWNT orientation by analyzing the variation in the film morphology with ultrasonication time. The method for aligning SWNTs normal to the electrode may be competitive with chemical vapor deposition or screen printing, the predominant methods by which vertically aligned SWNT films have been fabricated to date. We also focused on the 3-D networking of SWCNTs that can offer the nano-sized electrodes with large surface area to the SWCNTs-based potential applications including solar-cells, chemical- and bio-sensors, and etc. The 3-D networks of SWCNTs were fabricated by synthesizing SWCNTs on the 3-D structures of Si substrates. The Si templates of hole and pillar structures were prepared by electrochemical etching and conventional deep etching processes, respectively. By forming catalyst nanoparticles on the above Si templates using a dipping method, the SWCNTs were uniformly synthesized with desired density on those 3-D structures of Si substrates. We expect that the 3-D networks of SWCNTs will be useful as highly efficient electrodes for the potential applications in the fields of future electronics and energy alternatives.