Fluidic assembly of highly organized single-wall carbon nanotubes in nano and micro scales: characterization and investigation of the assembly mechanism.

• Online Access: http://hdl.handle.net/2047/d10019340

I present the liquid-phase fabrication of highly organized single-walled carbon nanotube (SWNT) networks. Using lithographically patterned template assisted dip coating method, SWNTs are directly assembled into pre-designed micro- and nano-scale 1805 and poly methyl methacrylate (PMMA) channels forming densely packed SWNT lateral networks in diverse geometries with pattern width ranging from 150 nm to 10 μm. The nanotubes also become highly aligned as 1805/PMMA template channel width shrinks, leading to a better control of assembled SWNT morphology. Very large scale patterned SWNT networks were also fabricated. Chemical and physical properties of the substrate were characterized using several surface characterization techniques to investigate and control the mechanism of SWNT assembly. We found that hydrophilic chemical groups such as hydroxides were created on the silicon or silicon oxide surface through the controlled plasma treatment and fluidic SWNT dip-coating process. Also we found that nanoscale rough surface structures formed during the plasma treatment significantly increased the number of dangling bonds and hydroxide functional groups on the surface. These combined chemical and physical enhancements that attract the SWNT in the aqueous solution enable us to build highly organized and very large scale SWNT network architectures effectively in various dimensions and geometries. Room temperature, two and four probe I-V characterization of fabricated high coverage SWNT wires shows linear ohmic behavior. This work provides a simple and flexible way of building nanotube-based electronics in a variety of dimensions with high-rate.