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: Graphene and diamonds prove a slippery combination

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

Related Stories

Recommended for you

Graphene and diamonds prove a slippery combination

14 hours ago

Scientists at the U.S. Department of Energy's Argonne National Laboratory have found a way to use tiny diamonds and graphene to give friction the slip, creating a new material combination that demonstrates ...

Artificial muscles get graphene boost

May 22, 2015

Researchers in South Korea have developed an electrode consisting of a single-atom-thick layer of carbon to help make more durable artificial muscles.

How to make continuous rolls of graphene

May 21, 2015

Graphene is a material with a host of potential applications, including in flexible light sources, solar panels that could be integrated into windows, and membranes to desalinate and purify water. But all ...

Carbon nanothreads from compressed benzene

May 20, 2015

A new carbon nanomaterial – the thinnest possible one-dimensional thread that still retains a diamond-like structure – was created by the controlled, slow compression and decompression of benzene. The ...

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."

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.