Issue Eur. Phys. J. Appl. Phys. Volume 44, Number 2, November 2008 Page(s) 149 - 153 Section Nanomaterials and Nanotechnologies DOI 10.1051/epjap:2008154 Published online 19 August 2008

Eur. Phys. J. Appl. Phys. 44, 149-153 (2008)
DOI: 10.1051/epjap:2008154

Effects of plasma power on the growth of carbon nanotubes in the plasma enhanced chemical vapor deposition method

Y. Abdi^{1, 2}, E. Arzi¹ and S. Mohajerzadeh<sup>2

1</sup>  Nano-Physics Research Laboratory, Department of Physics, University of Tehran, Tehran, Iran
²  Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran

Arzi@khayam.ut.ac.ir

Received: 23 December 2007 / Received in final form: 12 April 2008 / Accepted: 2 July 2008 / Published online: 19 August 2008

Abstract
Effects of plasma power on the growth of the multi-wall carbon nanotubes (CNTs) are reported. CNTs were grown on the silicon wafers by plasma enhanced chemical vapor deposition (PECVD) method using a mixture of acetylene and hydrogen at the temperature of 650 °C. Plasma powers ranging from zero to 35 W were applied on the samples and the effects of different magnitudes of the plasma power on the growth direction of the CNTs were investigated. Regular vertically aligned nanotubes were obtained at plasma power of 25 W. In order to set on the plasma during the growth, electrical force was applied on the carbon ions. Nickel layer was used as a catalyst, and prior to the nanotubes growth step, it was treated by hydrogen plasma bombardment in order to obtain the Ni nano-islands. In this step, as the plasma power on the Ni layer was increased, the grain size of nickel nano-particles decreased, and hence, nanotubes of smaller diameter were obtained later on. At the last step some anomalous structures of agglomerated CNTs were obtained by controlling the plasma power. Samples were analyzed by scanning tunneling microscopy (STM) and scanning electron microscopy (SEM).

PACS
61.46.Fg - Nanotubes.
81.07.De - Nanotubes.

© EDP Sciences 2008

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