Researchers move graphene electronics into 3D

Feb 02, 2012
Artistic impression of graphene molecules. Credit: University of Manchester

In a paper published this week in Science, a Manchester team lead by Nobel laureates Professor Andre Geim and Professor Konstantin Novoselov has literally opened a third dimension in graphene research. Their research shows a transistor that may prove the missing link for graphene to become the next silicon.

Graphene – one atomic plane of carbon – is a remarkable material with endless unique properties, from electronic to chemical and from optical to mechanical.

One of many potential applications of graphene is its use as the basic material for computer chips instead of . This potential has alerted the attention of major chip manufactures, including IBM, Samsung, Texas Instruments and Intel. Individual transistors with very high frequencies (up to 300 GHz) have already been demonstrated by several groups worldwide.

Unfortunately, those transistors cannot be packed densely in a computer chip because they leak too much current, even in the most insulating state of graphene. This electric current would cause chips to melt within a fraction of a second.

This problem has been around since 2004 when the Manchester researchers reported their Nobel-winning graphene findings and, despite a huge worldwide effort to solve it since then, no real solution has so far been offered.

The University of Manchester scientists now suggest using graphene not laterally (in plane) – as all the previous studies did – but in the vertical direction. They used graphene as an electrode from which electrons tunnelled through a dielectric into another metal. This is called a tunnelling diode.

Then they exploited a truly unique feature of graphene – that an external voltage can strongly change the energy of tunnelling electrons. As a result they got a new type of a device – vertical field-effect tunnelling transistor in which graphene is a critical ingredient.

Dr Leonid Ponomarenko, who spearheaded the experimental effort, said: "We have proved a conceptually new approach to graphene electronics. Our transistors already work pretty well. I believe they can be improved much further, scaled down to nanometre sizes and work at sub-THz frequencies."

"It is a new vista for graphene research and chances for graphene-based electronics never looked better than they are now", adds Professor Novoselov.

Graphene alone would not be enough to make the breakthrough. Fortunately, there are many other materials, which are only one atom or one molecule thick, and they were used for help.

The Manchester team made the transistors by combining graphene together with atomic planes of boron nitride and molybdenum disulfide. The were assembled layer by layer in a desired sequence, like a layer cake but on an atomic scale.

Such layer-cake superstructures do not exist in nature. It is an entirely new concept introduced in the report by the Manchester researchers. The atomic-scale assembly offers many new degrees of functionality, without some of which the tunnelling transistor would be impossible.

"The demonstrated transistor is important but the concept of atomic layer assembly is probably even more important," explains Professor Geim. Professor Novoselov added: "Tunnelling transistor is just one example of the inexhaustible collection of layered structures and novel devices which can now be created by such assembly.

"It really offers endless opportunities both for fundamental physics and for applications. Other possible examples include light emission diodes, photovoltaic devices, and so on."

Explore further: Thinnest feasible nano-membrane produced

More information: Field-effect tunneling transistor based on vertical graphene heterostructures, by L. Britnel et al., Science, 2nd February 2012.

Related Stories

Graphene's 'Big Mac' creates next generation of chips

Oct 09, 2011

The world's thinnest, strongest and most conductive material, discovered in 2004 at the University of Manchester by Professor Andre Geim and Professor Kostya Novoselov, has the potential to revolutionize material ...

IBM introduces new graphene transistor

Apr 11, 2011

(PhysOrg.com) -- In a report published in Nature, Yu-ming Lin and Phaedon Avoris, IBM researchers, have announced the development of a new graphene transistor which is smaller and faster than the one they i ...

Self-cooling observed in graphene electronics

Apr 03, 2011

With the first observation of thermoelectric effects at graphene contacts, University of Illinois researchers found that graphene transistors have a nanoscale cooling effect that reduces their temperature.

Recommended for you

Thinnest feasible nano-membrane produced

Apr 17, 2014

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

Wiring up carbon-based electronics

Apr 17, 2014

Carbon-based nanostructures such as nanotubes, graphene sheets, and nanoribbons are unique building blocks showing versatile nanomechanical and nanoelectronic properties. These materials which are ordered ...

Making 'bucky-balls' in spin-out's sights

Apr 16, 2014

(Phys.org) —A new Oxford spin-out firm is targeting the difficult challenge of manufacturing fullerenes, known as 'bucky-balls' because of their spherical shape, a type of carbon nanomaterial which, like ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

lengould100
not rated yet Feb 02, 2012
Is this the breakthrough needed to implement the Optical Rectenna photovoltaic cell? Last I heard, it was only waiting a cheap diode which could connect to a nanotube antenna and operate at the frequency of photons of light.
Argiod
2.2 / 5 (6) Feb 03, 2012
...leading the way to an implantable super computer that can be placed inside the skull and neurally linked directly to the brain... ? Looks like the start of the design and construction of true cyborgs...
Resistance is futile...
ragarain
5 / 5 (1) Feb 03, 2012
yes, indeed.
'layer-cake superstructures' <<< i know i heard that somewhere before... oh yes: http://www.jle.co...88sl.jpg (cortical layer structure)
rawa1
1.2 / 5 (5) Feb 03, 2012
It's not clear for me, in which aspect the graphene diodes are fundamentally better than classical tunnel diodes with metallic contacts, which could be manufactured a way easier (the smart part there is the dielectric layer - not the electrode layer). Anyway, there is a preprint, so you can find it yourself. http://arxiv.org/...4999.pdf
rawa1
1 / 5 (3) Feb 03, 2012
Researchers moved the glass with graphene into 2D http://news.scien...l?ref=hp

More news stories

'Exotic' material is like a switch when super thin

(Phys.org) —Ever-shrinking electronic devices could get down to atomic dimensions with the help of transition metal oxides, a class of materials that seems to have it all: superconductivity, magnetoresistance ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.