Carbon nanotube synthesis from propane decomposition on a pre-treated Ni overlayer

TL;DR

This study demonstrates the synthesis of carbon nanotubes via propane decomposition on a pre-treated Ni overlayer using APCVD, with detailed analysis confirming the structural and growth mechanisms of the nanotubes.

Contribution

It introduces a method for growing CNTs on Si(111) with a pre-treated Ni catalyst, providing insights into catalyst behavior and nanotube structure.

Findings

Catalyst particles are at the nanotube tips, indicating tip growth mechanism.

CNTs are graphitic with well-ordered graphene layers.

Radial breathing modes confirm multi-wall nanotube formation.

Abstract

Growth of carbon nanotubes (CNTs) was performed by atmospheric pressure chemical vapour deposition (APCVD) of propane on Si(111) with a pre-treated Ni overlayer acting as a catalyst. Prior to the growth of CNTs, a thin film of Ni was deposited on Si(111) substrate by evaporation and heat treated at 900{\deg}C. The growth of nanotubes was carried out at 850{\deg}C using propane as a source of carbon. Distribution of the catalyst particles over the Si substrate was analysed before and after heat treatment by atomic force microscopy (AFM). The X-ray diffraction (XRD) pattern of the grown material revealed that they are graphitic in nature. Field emission scanning electron microscopy (FESEM) was used to investigate the growth process and it was found that a catalytic particle was always situated at the tip of the tube thus implying a tip growth mechanism. Evidence for the presence of radial breathing mode from multi-wall nanotubes (MWNTs) in the grown sample was obtained from micro-Raman analysis. Finally, high-resolution transmission electron microscopic (HRTEM) analysis confirmed that the graphene layers of the CNTs are well ordered with typical 0.34 nm spacing.