Spot-welding graphene nanoribbons atom by atom

Jun 13, 2013
Spot-welding graphene nanoribbons atom by atom

Scientists at Aalto University and Utrecht University have created single atom contacts between gold and graphene nanoribbons.

In their article published in Nature Communications, the research team demonstrates how to make electrical contacts with single chemical bonds to graphene nanoribbons. Graphene is a single layer of arranged in a . It is anticipated to be a revolutionising material for future electronics.

Graphene transistors functioning at room temperature require working at the size scale of less than 10 nanometres. This means that the graphene nanostructures have to be only a few tens of atoms in width. These transistors will need atomically precise electrical contacts. A team of researchers have now demonstrated experimentally how this can be done.

In their article the scientists address the problem by demonstrating how a single chemical bond can be used to make an to a graphene nanoribbon.

"We cannot use alligator clips on the atomic scale. Using well-defined is the way forward for graphene nanostructures to realise their potential in ," says Professor Peter Liljeroth who heads the Physics group at Aalto University.

The team used (AFM) and scanning tunnelling microscopy (STM) to map the structure of the graphene nanoribbons with . The researchers used voltage pulses from the tip of the scanning tunnelling microscope to form single bonds to the graphene nanoribbons – precisely at a specific atomic location. The pulse removes a single hydrogen atom from the end of a graphene nanoribbon and this initiates the .

"Combined AFM and STM allows us to characterise the graphene nanostructures atom-by-atom, which is critical in understanding how the structure, the bonds with the contacts and their electrical properties are related," explains Dr Ingmar Swart who leads the team concentrating on STM and AFM measurements at Utrecht University

Combining the microscopy experiments with theoretical modelling, the team developed a detailed picture of the contacted nanoribbon properties. The most significant discovery is that a single chemical bond forms an electronically transparent contact with the graphene nanoribbon – without affecting its overall electronic structure. This may be the key to using graphene nanostructures in future electronic devices, as the contact does not change the intrinsic ribbon properties.

"These experiments on atomically well-defined structures allow us to quantitatively compare theory and experiment. This is a great opportunity to test novel theoretical ideas," concludes Dr Ari Harju, leader of the theoretical team in the project at Aalto University.

The study was performed at Aalto University Department of Applied Physics and at the Debye Institute in Utrecht University. The groups at Aalto are part of the Academy of Finland's Centres of Excellence in "Low Temperature Quantum Phenomena and Devices" and "Computational Nanosciences". Academy of Finland and the European Research Council ERC funded the research.

The article is titled "Suppression of electron-vibron coupling in graphene nanoribbons contacted via a single atom."

Explore further: First-ever high-resolution images of a molecule as it breaks and reforms chemical bonds

More information: www.nature.com/ncomms/2013/130612/ncomms3023/full/ncomms3023.html

Related Stories

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 : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

El_Nose
not rated yet Jun 13, 2013
but is this scaleble to a substrate containing 1.5 billion potential connections
sennekuyl
not rated yet Jul 18, 2013
It does sound like it is something that can be automated so I'm going to go with "Yes, probably."

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...