Growth process of vertically aligned single-walled carbon nanotubes

Abstract

We have performed a systematic investigation of the influence of growth parameters on the synthesis of vertically aligned single-walled carbon nanotubes (VA-SWNTs) by the alcohol catalytic chemical vapor deposition (ACCVD) method. The growth process of the VA-SWNTs was monitored using an in situ optical absorbance technique and the effects of CVD temperature and ethanol pressure on the initial growth rate and the catalyst lifetime were investigated. We found that for a given CVD temperature, there is an optimum pressure at which VA-SWNT film growth is maximized, and this pressure increases with temperature. Below this optimum pressure, the growth reaction is first-order, with the arrival of ethanol to the catalyst being the rate-limiting step. The activation energy of the growth reaction was determined to be approximately 1.5 eV.The root-growth mechanism of VA-SWNTs synthesized by the alcohol CVD method was also confirmed by a two-stage growth process. Following a short growth period using normal ethanol, 13 C -labeled ethanol was introduced to continue the growth. The location of the 13 C was determined from resonance Raman spectra, confirming the root-growth mechanism.

Enhanced Control of Single-Walled Carbon Nanotube Properties Using MPCVD with DC Electrical Bias

“…Although direct synthesis of vertically aligned or vertically oriented SWNT arrays has been commonly reported in the literature Maruyama, et al, 2005;Murakami, et al, 2004;Zhong, et al, 2005), most refer to a general packing of SWNTs of subsequent density that the growth front advances and remains in plane with the originating growth substrate. Closer examination of these arrays clearly reveals that individual CNTs within the array exhibit significant waviness and inconsistent orientation with respect to the substrate.…”

Data-driven understanding of collective carbon nanotube growth by in situ characterization and nanoscale metrology

“…7(f) and 7(g)]. 43,54 Importantly, different carbon-containing feedstock gases were used in CVD growth of CNTs, including acetylene, 55 ethylene, 56 methane, 57 ethanol, 58 and carbon monoxide. 59 Moreover, other additives were explored to assist growth by either accelerating the growth rate or prolonging the catalyst life, such as water, oxygen, air, ethanol, carbon dioxide, acetone, tetrahydrofuran, methylbenzoate, and benzoaldehyde.…”

Simple Fabrication Technique for Field-Effect Transistor Array Using As-Grown Single-Walled Carbon Nanotubes

“…The details of SWNT synthesis procedures have been described in previous reports. [16][17][18] After SWNTs synthesis, the devices were characterized by a semiconductor parameter analyzer system (Agilent 4156C) and scanning electron microscopy (SEM; Hitachi S-4800, acceleration voltage at 1 kV). SEM observation was carried out after measuring the FET properties in order to avoid any damage to the SWNTs by electron irradiation, 19) which could result in an obvious change in the electronic properties 20) .…”