Single-Walled Carbon Nanotube Formation on Silicon Structures

We have fabricated single-walled carbon nanotubes (SWNTs) on silicon structures. The SWNTs are grown on the tops of silicon pillars, forming nanoscale connections between the pillars. The nanotubes are grown through a four-step process:

Step 1 is patterning a square array into photo-resist on top of a silicon wafer.
Step 2 is etching the wafer using a reactive ion etch to form straight-walled pillars.
Step 3 is applying a preformed catalyst precursor to the tops of the silicon pillars. The precursor consists of an alcohol solution in which metallic salts are dissolved, along with a block copolymer. The block copolymer gives structure to an aluminum oxide network that forms upon calcification. The resulting high surface area oxide supports metallic nanoparticles that act as catalysts for SWNT growth.
Step 4 is chemical vapor deposition (CVD) growth of SWNTs. The nanotubes are grown in a CVD reaction chamber using CO as the carbon-containing gas species.

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