Graphene-based chips a step closer, say researchers

Physicists have insulated graphene to make it more stable, and claim it could be a step towards new chip architectures

Manchester University researchers have claimed a breakthrough in graphene research which they say could contribute to new computer chip designs.

Dr Leonid Ponomarenko

Dr Leonid Ponomarenko of Manchester University and his colleagues have outlined a breakthrough in graphene research that could lead to new computer chip designs. Photo credit: University of Manchester

The researchers interleaved atom-thick graphene with boron nitride in four alternate layers. The boron nitride sandwiched one of the layers of graphene, insulating it and making it easier to study.

"We managed to isolate graphene from the environment," researcher Dr Leonid Ponomarenko told ZDNet UK on Monday. "It makes it insulated from outside humidity or any other chemicals. This is what you need when you are making a custom chip."

Graphene, a super-strong material one atom thick, has a hexagonal 'chicken-wire' structure. The material is very sensitive to atmospheric conditions such as humidity, according to Ponomarenko. Insulating the graphene with boron nitride gives the material consistent measurable properties as a step towards commercial production and use in chips.

"I think we've made an important step in this direction with graphene heterostructures," he said. "Give us another year to explore this area and find out a definite answer."

Ponomarenko said the sandwich-like structure of graphene and boron nitride, called a heterostructure, allows graphene that can be more closely controlled than before.

Graphene heterostructures

Graphene heterostructures are not just two layers of graphene with a spacer between them. The layers interact with each other, making the heterostructure a "completely new sort of a device", Ponomarenko said. In addition to conductivity of individual graphene sheets, the researchers can study other properties, such as tunnelling between layers and 'Coulomb drag' — a phenomenon in which current flowing in one of the layers causes potential drop in another layer.

At the moment the researchers are trying to find out whether these heterostructures can be of practical use as transistors themselves.

"So far we made insulating graphene only at cryogenic temperatures," said Ponomarenko. "Switching between conducting and insulating state at room temperature would mean a proper graphene transistor with a large on/off ratio — something that many groups around the globe are trying to achieve."

Ponomarenko worked with researchers from academic institutions including the University of Lancaster, the Institute for Microelectronics Technology, Chernogolovka, Russia, and the National Institute for Materials Science, Tsukuba, Japan. The researchers published a paper detailing their discoveries in Nature Physics on Monday.

Graphene research was promised £50m funding by chancellor George Osborne last week.


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