Investigation of the effective parameters in the growth of carbon nanotubes by thermal chemical vapour deposition method

Abstract

Synthesis and growth of carbon nanotubes (CNTs) from C 2 H 2 by thermal chemical vapour deposition (TCVD) using a mixture of different gases were investigated. A thin film of nickel was coated as catalyst on silicon substrates by ion beam sputtering technique. Various parameters such as thickness of oxide layer and time, as well as reduction temperature were investigated in view of obtaining the best conditions for CNTs growth. C 2 H 2 was very effective as carbon feedstock and NH 3 pretreatments were crucial steps towards obtaining a high density of nucleation sites for CNTs growth by inhibiting amorphous carbon generation in the initial stage of the synthesis. The substrate oxide layer was analysed by secondary ion mass spectrometry. The prepared CNTs were confirmed by Raman spectroscopy and were further characterised using scanning electron microscopy and transmission electron microscopy.

Diameter control of carbon nanotubes using argon–acetylene mixture and their application as IR sensor

“…The common practice of measuring the outer diameter of CNTs with the help of SEM results was followed, as suggested by many other independent researchers. [5][6][7]11,12 Also, extra care was taken and more than 80 measurements were averaged with best possible accuracy and precision.…”

“…6 CNTs offer unique properties making them attractive for use in optical, thermal, chemical, mechanical, electrical, electromechanical and biological applications. [7][8][9] Among several methods for synthesis of CNTs, chemical vapor deposition (CVD) technique offers certain advantages of low production cost, 1 high production yield, 10 scalability, growth on various substrates 11 and at much lower temperatures, to list a few. 12,13 During CVD process, the precursor source for carbon is pyrolytically decomposed and the subsequent influx of species at the nanoparticle surface promotes carbon dissolution and its supersaturation into the catalyst nanoparticle, thus leading to the crystallization of excess carbon in the form of cylindrical network with an outside diameter that corresponds to the average nanoparticle size.…”