Passivation oxide controlled selective carbon nanotube growth on metal substrates

Vertically aligned arrays of multi-wall carbon nanotubes (MWNT) are grown on Inconel (TM) 600, a nickel-based super-alloy. Using x-ray photoelectron spectroscopy (XPS) and chemical vapor deposition (CVD) growth of the MWNTs it is shown that a stable oxidation barrier is required for the stabilization of iron on the substrate and subsequent nanotube growth. This evidence for passivation oxide supported growth of MWNTs was then used to grow MWNTs on patterned oxidized substrates in a selective growth furnace. The unique advantage of this patterned growth on Inconel T 600 is found to be the chromia passivation layer's electrical conductivity (measured value of 1.08 mu Omega m), creating the opportunity for low resistivity electrodes made from nanotubes. Inconel substrates with 100 mu m long aligned MWNTs are demonstrated to exhibit an average resistance value of 2 Omega.