IBM boffins inch closer to nano-transistors

Researchers solve 'noisy' graphite problem

Shaun Nichols in California, vnunet.com 10 Mar 2008

Researchers at IBM claim to have cleared a major hurdle in the building of nanoscale transistors.

The company has solved an interference issue which had been perplexing researchers and preventing the construction of transistors from tiny particles of graphite.

The issue arises when scientists attempt to construct circuits with graphene, a 2D grid structure constructed from carbon atoms. The electrical properties of graphene make it an ideal replacement for larger silicon transistors.

But one major problem with graphene, the so-called 'atomic chicken wire' material, is that it is highly susceptible to interference.

Electrical signals bounce around the structure, affecting its normal operation and creating a condition known as 'Hooge's Rule'.

"The effect of noise from Hooge's Rule is exaggerated at the nanoscale because the dimensions are approaching the smallest limits, down to only a handful of atoms," explained IBM researcher Dr Phaedon Avouris.

"The noise that is created can overwhelm the electrical signal that needs to be achieved to be useful.

"In other words, you cannot produce any useful electronic device at the nanoscale if the noise is comparable to the signal you are trying to switch on and off."

The researchers overcame the problem by adding a second layer of graphene to the transistor. When two layers were used, the interference was reduced to a low enough level to allow the transistor to function normally.

IBM warned that more research is needed, but said that the graphene mesh could be used in future devices such as sensors, communication devices and computers.

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