Graphene contemplates career as perfect photodetector

One of graphene’s more intriguing qualities is that it is capable of absorbing light of any colour. This makes it less useful than silicon for making logic switches, because it is hard to switch off, but means it might just make a name for itself in solar panels.

Silicon, while happy to absorb lots of light, is very picky and can only accommodate a few frequencies. Graphene is the opposite: it is non discriminatory, accepting photons from any neighbourhood on the EM spectrum, but it only collects three per cent of the light that falls on its surface.

Now, researchers in the UK have demonstrated a device based on a graphene metallic mix that can capture up to twenty times as much light as graphene on its own, letting the material absorb half of incident light.

Per PhysicsWorld, the Institute of Physics’ news site, a team of scientists drawn from Cambridge and Manchester Universities have paired graphene up with "plasmonic nanostructures".

Nice terminology, but what does it mean? The publication explains: "These are metal devices that enhance local electromagnetic fields in a material by coupling incoming light with electrons on the surface of the metal. The nanostructures are fabricated on top of graphene samples to concentrate the electromagnetic field in the region of the material where light is converted to electrical current, so as to dramatically increase the generated photovoltage."

Andrea Ferrari, Cambridge’s lead researcher, said that the work was the first step towards "perfect" photodetectors.

The research is published in Nature Communications here.