Bilayer graphene concept (via Loretta Kuo and Michelle Groce, University of Maryland)
Graphene is becoming the main ingredient in innovation. Since its discovery scientists have used its unique properties to create many useful devices with extraordinary properties, if only to make our vodka stronger. The latest creation to come from graphene is a photo detector able to detect a very wide range of wave frequencies. Acting as a photo detector, it has the potential to have a very wide range of applications it may be used for, from security scanners to detecting dark energy.
Researchers at the University of Maryland have created a bolometer using bilayer (two atom thin sheets) graphene. The unique properties associated with graphene give the device the capability of detecting light energies ranging from terahertz frequencies to visible light frequencies. The graphene layer has a bandgap of exactly zero energy, distinguishing it from other photo detectors. (Finally, a use for graphene's one weakness, the bandgap) The zero energy bandgap allows it to absorb photons of any energy. In addition, it will be able to detect very low energy photons such as infrared and sub-millimeter waves that pass through currently used semiconductor photo detectors.
The bilayer graphene bolometer is particularly attractive in the field of astronomy. Photons of submillimeter waves are emitted from early-stage formations of stars and galaxies. By examining these interstellar clouds of molecules astronomers can get a deeper understanding of redshifts and masses of distant beginning galaxies. Furthermore, it may help us research dark energy and structure development in our universe.
However, more work is to be done before a device can be put together using bilayer graphene. The electrical resistance in the bilayer graphene bolometer is extremely high. This creates a problem when working at high frequencies and very little incident light gets absorbed. Despite the drawbacks the team continues to work on new designs for the device and staying optimistic about graphene's future in photo detecting devices.
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