Synthesis of free-standing carbon nanotube electrodes using plasma-enhanced chemical vapor deposition

Abstract

In this presentation, the synthesis of multi-walled carbon nanotubes (MWCNTs) has been investigated to fabricate the nano-electrodes. MWCNTs were grown on a TiN coated quartz plate with Fe catalysts patterned by UV nano-imprint lithography (NIL)1. The proposed study is the realization of a simple, inexpensive and reproducible method to produce nanoscale electrode arrays in large areas. The patterns were defined by an array of circles 200 nm in diameter, and 500 nm in pitch. The nano-patterned master and Fe catalyst are observed with good pattern fidelity over a large area by atomic force microscope (AFM) and scanning electron microscopy (SEM). Among various synthesis methods for carbon nanotube growth, plasma-enhanced chemical vapor deposition (PECVD)2 was used for the growth of vertically aligned multi-wall carbon nanotube arrays. Ammonia (NH3) and acetylene (C2H2) were used as the etchant gases and the carbon source, respectively. The carbon nanotubes were vertically aligned in high density on a large area of the plain quartz substrates. High-resolution transmission electron microscopy (TEM) analysis reveals that the synthesized CNTs have multi-walls and bamboo-like structures. Patterned catalysts made it possible to allow the precise placement of individual CNT electrodes on the substrate. These electrodes have diameters ranging from 50 nm to 100 nm and lengths of about 300 nm. A field emission test using isolated CNTs on quartz plates showed the ability of CNTs as nano-electrodes. Bio compatibility was also investigated by cell culturing on the fabricated CNTs/quartz template for potential bio-applications.