Growth of Single-Walled Carbon Nanotubes Rooted from Fe/Al Nanoparticle Array

Abstract

We explored the growth of single-walled carbon nanotubes (SWNTs) from nanoparticle array made of an Fe/Al multilayer catalyst by thermal chemical vapor deposition. Fe nanoparticles with a high number density and a narrow size distribution (1-5 nm) were efficiently formed by annealing the Fe/Al thin layer, resulting in the high-yield growth of SWNTs. Moreover, it was found that isolated SWNTs are rooted from patterned Fe/Al islands. The SWNTs bridged between electrodes exhibited semiconducting and metallic properties.

Low Temperature Synthesis of Single-Walled Carbon Nanotubes in an Inductively Coupled Plasma Chemical Vapor Deposition System

“…28 29 Figure 2 shows the SEM micrographs and AFM surface morphologies of the bi-layered catalysts after the preheating process in the H 2 atmosphere. In comparison, nanoclusters from Fe1/Al10 bi-layered thin films are uniformly distributed with uniform size distributions, where the surface mean roughness is 2.94 nm, similar to the previous reports by Wongwiriyapan et al 29 On the other hand, for the Ni1/Al10 catalysts it shows a smaller mean roughness of 1.04 nm, whereas some larger aggregations are also observed. 26 This might be a result of different catalystsubstrate interaction, i.e., Fe-Al x O y and Ni-Al x O y , for the preheating condition we used.…”

“…Bi-layered thin-film catalysts (Fe1/Al10 (-1) 29 and Ni1/Al10 (-2), 26 27 numbers in the unit of nm) were deposited by electron-beam evaporation method on p-type Si (100) substrates having a layer of thermally grown oxides of a thickness 150 nm. Prior to the synthesis of SWNTs, substrates coated with the bi-layered thin-film catalysts were heated to 600 C to preanneal the catalysts under H 2 atmosphere (H 2 flow rate 100 sccm) of a pressure 1 Torr for a period of 20 min.…”

“…Transition metals (Fe, Co, Ni) with an addition of Al under-layer have been demonstrated an efficient way to grow SWNTs by thermal CVD at high temperature. [25][26][27][28][29] The partially-oxidized Al under-layer (i.e., Al x O y ) provides both large support areas and high surface roughness to prevent the nanoparticles from forming large size particles at high temperatures, thus enhancing the yields of SWNTs growth. [25][26][27][28][29] For the bi-layered thin-film catalysts used in this study, we have also confirmed the formation of Al x O y after the preannealing process by characterization tools such as X-ray photoelectron spectroscopy (XPS, data not shown).…”

Synthesis of Nanostructured Hybrid between Carbon Nanotube and Inorganic Material towards Nanodevice Application

“…Compared with the Fe catalyst, using the Fe/Al multilayer catalyst, the size distribution of the catalyst nanoparticles was narrow and the nanoparticles were small. The XPS spectrum of the sample indicated the formation of Al x O y [10]. From this result, the catalyst nanoparticle array is likely to be formed as follows: (1) Al layers are oxidized by residual oxygen inside the furnace, forming thermally stable Al x O y clusters.…”

Role of Reaction and Factors of Carbon Nanotubes Growth in Chemical Vapour Decomposition Process Using Methane—A Highlight

“…Though the transition metals can decompose hydrocarbons, they need a support for the growth of nanotubes. Materials like silica [56,57], alumina [58,59], zeolite [44], and recently MgO [60][61][62] were used as supports for active metals in developing different forms of carbon nanostructures like SWNT, DWNT, MWNT, and nanofibres. Different catalyst preparation techniques like impregnation [63][64][65][66][67][68][69], coprecipitation [70], sol-gel technique [71][72][73], thin film deposition using electron beam evaporation, and photolithography [74] for patterned catalyst on the support were studied.…”