Number of Walls Controlled Synthesis of Millimeter-Long Vertically Aligned Brushlike Carbon Nanotubes

Abstract

Millimeter (mm) long vertically aligned carbon nanotubes (CNTs) were grown by the catalyst assisted thermal chemical vapor deposition (CVD) technique. The continuous growth of CNTs as long as 7 mm was observed after 12 h of deposition by adjusting the growth parameters for making the catalyst active for a long time. The direct dependence of the number of walls of mm-long CNTs on the Fe catalyst thickness was observed. The successful syntheses of single-walled nanotubes (SWNTs), double-walled nanotubes (DWNTs), and multiwalled nanotubes (MWNTs) with high percentages (∼80%) were achieved by varying the catalyst layer thickness. The effect of Al 2 O 3 buffer layer was found to be critical for this controlled synthesis, which has been discussed in detail. The possible growth mechanism is also discussed to better understand this phenomenon.

Experimental Investigation of Adhesive Behavior in Carbon Nanotube Based Gecko Tape

“…Brush-like CNTs were grown using a catalytic chemical vapor deposition (CVD) process with a carbon source such as ethylene and He and H 2 (G1 Grade; Taiyo Nippon Sanso Corp., Tokyo, Japan) containing a small amount of moisture [8]. The Fe (4 N; Hitachi High-Technologies Corp., Tokyo, Japan) catalyst layer was deposited on Si substrates [P(100), 525-mm Fukui thickness; KST World Corp., Fukui City, Japan].…”

Gold-coated carbon nanotube electrode arrays: Immunosensors for impedimetric detection of bone biomarkers

“…Vertically aligned carbon nanotube posts (VACNTs) were grown on Si-wafers using thermal chemical vapor deposition (CVD) process as described in the earlier reports (Chakrabarti et al, 2007;Landis et al, 2010;Yun et al, 2006). The annealed posts were peeled individually from the silicon wafer, mounted in non-conducting epoxy, and degassed for at least 30 min to remove any bubbles.…”

“…The facile bottom-up approach to grow them is particularly well suited as the growth conditions may be modified to achieve specific properties to fit and meet the needs for sensor integration (Chakrabarti et al, 2007;Landis et al, 2010;Yun et al, 2006). Studies have also been performed to understand the influence of the nanotube side walls, tips and their size, on their electron transfer kinetics (Gong et.…”

Application of Carbon Nanotubes Directly Grown on Aluminum Foils as Electric Double Layer Capacitor Electrodes

“…In this case, the nanotubes are forced to proceed vertically due to the steric hindrance from adjacent nanotubes. It was reported recently that iron catalyst particles stabilized in an alumina matrix result in millimeter-long, vertically aligned, brush-like CNTs at a temperature of 750 8C or more, [26,35,36] however, in the case of Al foil, CNTs should be synthesized necessarily at a temperature lower than 660 8C to prevent melting of the substrate. Such a temperature, which is quite low for efficient CCVD, leads to a decelerating performance of most , and b) the mean value and standard deviation of capacitance of corresponding electrodes calculated using data presented in Figure 5a.…”