Rapid fabrication of CNT sensors using electro-chemical deposition of functionalized CNTs

We present a novel fabrication technique to fabricate functionalized CNT sensors rapidly using electro-chemical deposition method. The basic fabrication process of this sensor includes fabrication of a gold (Au) microelectrode array by photolithography process, functionalization of multi-walled carbon nanotubes (MWNTs) with carboxylic acid groups (-COOH), and electro-chemical deposition of functionalized MWNTs (f-CNTs) on the Au microelectrode array. The adhesion between the f-CNTs and the Au microelectrodes could be enhanced if CNT sensors are built using the process described in this paper. The I-V characteristics of the sensors were investigated. Our experimental results show that CNT sensors fabricated by electro-chemical process have dramatically different I-V characteristics compared with sensors fabricated by DEP or AFM manipulation techniques. The power limit of the sensors ranges from 0.28mW to 6.21mW, which is much higher than most reported CNT sensors. Self-heating effect can be induced at input power of ∼2.2mW. Based on these experimental results, we think that the novel f-CNT sensors should be investigated further for applications in thermal, mechanical, and biomedical systems. © 2007 IEEE.