Research pushes the boundaries of electron microscopy to unlock the potential of graphene

November 15, 2012
The atomic resolution Z-contrast images show individual silicon atoms bonded differently in graphene.

(—Electron microscopy at the Department of Energy's Oak Ridge National Laboratory is providing unprecedented views of the individual atoms in graphene, offering scientists a chance to unlock the material's full potential for uses from engine combustion to consumer electronics.

Graphene crystals were first isolated in 2004. They are two-dimensional (one-atom in thickness), harder than diamonds and far stronger than steel, providing unprecedented stiffness, electrical and thermal properties. By viewing the atomic and bonding configurations of individual graphene atoms, scientists are able to suggest ways to optimize materials so they are better suited for specific applications.

In a paper published in , a team of researchers from Oak Ridge National Laboratory and Vanderbilt University used aberration-corrected to study the atomic and electronic structure of silicon in graphene.

The atomic resolution Z-contrast images show individual silicon atoms bonded differently in graphene.

"We have used new experimental and to reveal the bonding characteristics of individual impurities in graphene. For instance, we can now differentiate between a non-carbon atom that is two-dimensionally or three-dimensionally bonded in graphene. In fact, we were finally able to directly visualize a bonding configuration that was predicted in the 1930s but has never been observed experimentally," said ORNL researcher Juan-Carlos Idrobo.

Electrons in orbit around an atom fall into four broad categories – s, p, d and f – based on factors including symmetry and .

"We observed that silicon d-states participate in the bonding only when the silicon is two-dimensionally coordinated," Idrobo said. "There are many elements such as chromium, iron, and copper where the d-states or d-electrons play a dominant role in determining how the element bonds in a material."

By studying the atomic and of graphene and identifying any impurities, researchers can better predict which elemental additions will improve the material's performance.

Slightly altering the chemical makeup of graphene could customize the material, making it more suitable for a variety of applications. For example, one elemental addition may make the material a better replacement for the platinum catalytic converters in cars, while another may allow it to function better in electronic devices or as a membrane.

Graphene has the potential to replace the inner workings of electronic gadgets people use every day because of its ability to conduct heat and electricity and its optical transparency. It offers a cheaper and more abundant alternative to indium, a limited resource that is widely used in the transparent conducting coating present in almost all electronic display devices such as digital displays in cars, TVs, laptops and handheld gadgets like cell phones, tablets and music players.

Researchers expect the imaging techniques demonstrated at ORNL to be used to understand the atomic structures and bonding characteristics of atoms in other two-dimensional materials, too.

Explore further: Bilayer graphene is another step toward graphene electronics

Related Stories

Bilayer graphene is another step toward graphene electronics

August 11, 2011

The Nobel Prize winning scientists Professor Andre Geim and Professor Kostya Novoselov have taken a huge step forward in studying the wonder material graphene and revealing its exciting electronic properties for future electronic ...

Graphene applications in electronics and photonics

November 2, 2011

Graphene, which is composed of a one-atom-thick layer of carbon atoms in a honeycomb-like lattice (like atomic-scale chicken wire), is the world's thinnest material – and one of the hardest and strongest. Indeed, the ...

Topographical approaches to measuring graphene thickness

September 28, 2012

(—Graphene has long shown potential for use in electronics, but difficulties in producing the material to a high enough quality has so far prevented the commercialisation of graphene-based devices.

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Nov 16, 2012
Forget alchemy. We're CARBOMANCERS now :D

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.