Novel Carbon Nanostructures: Nanopipettes and Nano Nozzles

We present synthesis of two novel carbon nanostructures in the form of nanopipettes and nanonozzles. The synthesis of both nanopipettes and nanonozzles are highly reproducible. Nanopipettes synthesized using platinum thin film covered, diamond film coated wires at low CH4/H2 ratios, are tapered whiskers, having a shell containing helical graphitic sheets and a hollow core 1-20 nm in diameter throughout the length. Carbon nozzles, synthesized using Ga-Mo alloy film covered substrates at high CH4/H2 have an inner diameter of about 200nm at the base and 3- 4 microns at the end with a constant wall thickness of 30 nm throughout the length. These nozzles were typically filled with Ga at the tip and in some pockets along the length. We hypothesize that the mechanisms involved in the growth of nanopipette and nozzles are quite different than those suggested for the growth of multiwalled carbon nanotubes and other conical structures.