Tiny carbon nano octopi invade Surrey University

Friday 25 May 2012

The researchers have used inexpensive hydrocarbon gases in a chemical vapour deposition process to catalyse these nano-octopi with controlled numbers of legs and diameter.

These octopus-like carbon nanostructures consist of a central catalyst, made from nickel and copper, from which a number of carbon legs, as thin as 9 nanometres, radiate outwards. To give a sense of scale the head of a pin is about 1 million nanometres across.

These structures have low densities and a significantly higher surface area than a more conventional structure such as a carbon nanotube ‘forests’. The researchers used a unique photo-thermal chemical vapour deposition system, produced by Surrey NanoSystems Ltd, to create the carbon nano octopi at lower temperatures.

Conventional processes produce carbon octopi at temperatures greater than 900 °C, whereas the average substrate temperature during the process used in this study was ~400 °C, which would allow the carbon octopi to be deposited on many of the common substrates used in electronics.

Prof Ravi Silva FREng, Director of the Advanced Technology Institute and co-author said “As electronic devices continue to shrink in size, the components inside them follow a similar downsizing trend. This also has knock on effect in the current densities that need to be sourced through the contacts.

"Therefore, we need the materials used to facilitate this to be smaller and lighter, while maintaining a large enough surface area to volume ratio to function correctly. A possible solution to this problem has now arrived in the form of ‘carbon octopi nanostructures’”.

Prof Silva further said; “The technique used during this project could also enable the growth of the carbon nanostructures onto other two-dimensional materials such as graphene to produce an extremely low resistance all-carbon contacts.

"Such potential applications would help support the continued future trend towards smaller and more powerful electronic devices”.