Growth of a Single Free-Standing Multiwall Carbon Nanotube on Each Nano-Nickel Dot
This invention describes the process to achieve a patterned growth of freestanding carbon nanotube(s) on submicron dot(s) on silicon by plasma enhanced hot filament chemical vapor deposition (PE-HF-CVD). Using this method, devices requiring freestan ding vertical carbon nanotube(s) such as scanning probe microscopy, field emission flat panel displays, etc. can be fabricated without difficulty.
A thin film nickel grid has been fabricated on a silicon wafer by standard microlithographic techniq ues, and the PE-HF-CVD has been done using acetylene (C2H2) gas as the carbon source and ammonia (NH3) as a catalyst and dilution gas. Well-separated, single carbon nanotube obelisks were observed to grow on the grid. The structures had rounded bas e diameters of 150 nm, heights ranging from 0.1 to 5 micrometers, and sharp pointed tips. The diameter and height depend on the nickel dot size and growth time respectively. This nanotube growth process is compatible with silicon integrated circuit processing.
The invention is a novel way to grow single free-standing multiwall carbon nanotubes of any size and on any substrate as long as the substrate can survive 300 degree C. Growth only takes a few minutes. Carbon tube length is contro lled by growth time while diameter depends on dot size.
Categories: Nanotechnology Patents Issues: 6,863,942
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