"This extremely simple technique is suitable for the industrial low-cost manufacture of carbon nanofibres," Nan Jiang of the University of Tokushima told nanotechweb.org. "We hope that the industrial application will be realized within three to five years."

The scientists used simplified hot-filament chemical-vapour deposition (SHFCVD) equipment to produce carbon nanofibres of between 2 and 3 µm long, with an average diameter of less than 100 nm.

"The SHFCVD apparatus used in our laboratory was originally prepared for the deposition of diamond films," explained Jiang. "Occasionally, we found this apparatus to be more effective for the deposition of carbon nanofibres when catalytic substrates were used. Since carbon nanotubes and carbon nanofibres are very promising nanomaterials, we decided to fabricate them by the SHFCVD method."

The researchers tried a range of thicknesses of the nickel catalyst, from 10 to 200 nm, but found that the optimum carbon nanofibre growth occurred for a 30 nm thick nickel coating.

"To meet the actual requirements of industrial application, we plan to enlarge the reaction chamber and adjust the filament configuration to increase the carbon nanofibre output," added Jiang.

The researchers reported their work in Applied Physics Letters.