Writing in the journal Nature Communications, a collaboration between the Universities of Manchester and Cambridge, which includes Nobel Prize winning scientists Professor Andre Geim and Professor Kostya Novoselov, has discovered a crucial recipe for improving characteristics of graphene devices for use as photodetectors in future high-speed optical communications.
By combining graphene with metallic nanostructures, they show a twentyfold enhancement in harvesting light by graphene, which paves the way for advances in high-speed internet and other communications.
By putting two closely-spaced metallic wires on top of graphene and shining light on this structure, researchers previously showed that this generates electric power. This simple device presents an elementary solar cell.
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 major stumbling block towards practical applications for these otherwise very promising devices has so far been their low efficiency. The problem is that graphene – the thinnest material in the world – absorbs little light, approximately only 3%, with the rest going through without contributing to the electrical power.
The Manchester researchers have solved the problems by combining graphene with tiny metallic structures, specially arranged on top of graphene.
These so-called plasmonic nanostructures have dramatically enhanced the optical electric field felt by graphene and effectively concentrated light within the one-atom-thick carbon layer.....