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Graphene Pioneers Geim, Novoselov Work Improves Light Capture by 20x

by Editor1 last modified September 02, 2011 - 15:04

A collaboration between the University of Manchester and University of Cambridge reports a novel way to improve high-speed characteristics of graphene devices. The work could be used in photodetectors, optical communications – and even a lightning-fast Internet. The team includes Nobel Prize winning scientists Professor Andre Geim and Professor Kostya Novoselov.

Graphene Pioneers Geim, Novoselov Work Improves Light Capture by 20x

The team found that by combining graphene with metallic nanostructures, they could demonstrate a 20-fold enhancement in harvesting light by graphene. It is this explosion in light-harvesting capability which could pave the way for advances in high-speed internet and other communications, according to researchers.

Graphene was discovered at The University of Manchester in 2004, and resulted in the 2010 Nobel Prize in Physics being awarded to Geim and Novoselov for "groundbreaking experiments regarding the two-dimensional material graphene.”.

Professor Andrea Ferrari, from the Cambridge Engineering Department, who lead the Cambridge effort in the collaboration, said "So far, the main focus of graphene research has been on fundamental physics and electronic devices. These results show its great potential in the fields of photonics and optoelectronics, where the combination of its unique optical and electronic properties with plasmonic nanostructures, can be fully exploited, even in the absence of a bandgap, in a variety of useful devices, such as solar cells and photodetectors"

More importantly for applications, such graphene devices can be incredibly fast, tens and potentially hundred times faster than communication rates in the fastest internet cables, which is due to the unique nature of electrons in graphene, their high mobility and high velocity.

The Next Step in Supercharging Graphene’s Properties
A major stumbling block in using graphene for commercial application has been graphene’s inability to absorb large amounts of light. Presently, graphene only absorbs approximately only 3%, with the rest going through without contributing to the electrical power. Light passes through graphene so easily large because it is one of the world’s thinnest substances.

Researchers solved this problems by combining graphene with plasmonic nanostructures. The result is a dramatically enhanced optical electric field felt by graphene, which in turn effectively concentrates light within the one-atom-thick carbon layer.

By using the plasmonic enhancement, the light-harvesting performance of graphene was boosted by twenty times, without sacrificing any of its speed. The future efficiency can be improved even further, said Dr. Alexander Grigorenko, an expert in plasmonics and a leading member of the team.

"Graphene seems a natural companion for plasmonics. We expected that plasmonic nanostructures could improve the efficiency of graphene-based devices but it has come as a pleasant surprise that the improvements can be so dramatic," Dr. Grigorenko said.

Prof. Novoselov added: "The technology of graphene production matures day-by-day, which has an immediate impact both on the type of exciting physics which we find in this material, and on the feasibility and the range of possible applications. Many leading electronics companies consider graphene for the next generation of devices. This work certainly boosts graphene's chances even further."

The work is published in the journal Nature Communications.