March Meeting Teems with Graphene Talks
By Eric Betz
Few discoveries in physics have yielded a Nobel prize as quickly as Konstantin Novoselov and Andre Geim’s 2004 breakthrough in graphene. Research on the subject has exploded in the seven years since then, and this year’s March Meeting strongly reflected that trend.
“It opened up this Pandora’s box” said Novoselov in his lecture at the meeting. “I’m sure it will keep us busy for quite a few years because of that.”
So many wanted to attend Novoselov’s lecture that the center divider had to be removed between the lecture hall Novoselov was scheduled to speak in and the room next door. Even then, many sat on the floor or leaned along the walls.
Beginning his lecture by chiding other graphene speakers for skipping their introductions because they said everyone else had already given one, Novoselov took the time to trace a history of the two-dimensional substance from the discovery of graphite 500 years ago, through buckyballs and carbon nanotubes and on to the current status of graphene research.
“Each of you has synthesized graphene many times,” he told the audience, adding that “every time you use a pencil, you create one-atom-thick layers of graphite on top of whatever surface you’re writing on.” The challenge for him and Geim in the beginning, he said, was sorting through their sample trying to find those one-nanometer-thick layers.
But nature hates low-dimensionality, he said, and much of the research that was presented at the meeting focused on trying to iron out the many difficulties associated with making something essentially two-dimensional.
Throughout the week, many talks described experimenting with different materials as substrates for synthesizing high quality graphene. Others dealt with trying to achieve the same by removing the substrate altogether.
Tomás Palacios, an associate professor of electrical engineering and computer science at MIT, said one of the major problems with graphene is that putting it in contact with metal will dramatically decrease its performance. Any residues that build up on the surface of a one-layer sample will drastically alter its properties, he said.
Palacios described graphene as “a great material looking for an application,” and said he’s currently working on realizing that potential by creating a graphene circuit.
He doesn’t expect graphene to compete with silicon as a material anytime soon, because silicon has been studied so thoroughly for more than a generation. However, graphene can still be beneficial in the short term because one can use it to create highly flexible and cheap electronics, he said.
“For the last several years graphene has been a material with enormous potential for many applications; now it’s time to start making devices,” said Palacios. “The next few months are going to be really exciting.”
Speaking at a press conference, Walter de Heer, a professor of physics at the Georgia Institute of Technology, pointed out that graphene had been discovered before the work in 2004 by Geim and Novoselov, showing a patent he held for “thin film graphite” in 2003. Though de Heer admitted that the graphene that existed in the early 2000s was “lousy,” he said that he had made measurements on graphene before Geim and Novoselov, but didn’t know it at the time.
He also challenged the idea that graphene would result in cheap electronics any time soon and instead asserted that it would create better, but far more expensive electronics that would ultimately lead to advances.
“In the 1900s, a shipbuilder would look at a balsa-wood-and bicycle-parts-designed airplane and say ‘what are you going to do with that’,” said de Heer.
Addressing de Heer’s comment, Novoselov later said that he never claimed to have “discovered” graphene, and readily conceded that parts of the discovery he received the Nobel Prize for were in place already. Instead, he says that his 2004 paper with Geim was chosen because of the major breakthroughs they were able to achieve when they used adhesive tape to create graphene.
“Graphene is the most active area in physics and may be the most active area in science” said Sankar Das Sarma, director of the Condensed Matter Theory Center at the University of Maryland. Das Sarma showed a graph that demonstrated the exponential rise in the number of papers published on graphene since 2004 and attributed the material’s rapid increase in popularity to Geim and Novoselov’s paper.
In his lecture, Novoselov also gave a glimpse at what the future might hold for a substance that is the strongest, stiffest and thinnest known. He said some of the most interesting applications arise, not from graphene itself, but instead from combining it with other materials in what he described as drawing with many different colored pencils.
He said we can now start to think about creating other two-dimensional materials, each with its own unique properties and benefits. “One of the highlights of the last few months is that you can now start with graphene and break it apart and put it back together to get new 3D crystals.”
For example, if you combine layers of graphene with layers of boron-nitride, hydrocarbons, or fluorographene–each carbon atom bound to one fluorine–you get entirely different materials.
“The real breakthrough of graphene isn’t its optical properties or its electrical properties,” said Novoselov, “it’s the opportunities for all these new materials.”