Active bandgap tuning of graphene for tunable photodetection applications

摘要

In a method for adjusting the sensitivity of a photodetector, the bandgap of the photodetection material is adjusted by inducing strain in the photodetection material. Such adjustments can be made in situ and continuously, in a reproducible and repeatable manner. In embodiments of the method, the photodetection material is graphene, carbon nanotubes or graphene nanoribbon. The use of graphene permits a dynamically-adjustable sensitivity over a dynamic range of radiation having wavelengths of 1.38 microns or less, up to at least 60 microns. In an adjustable photodetector, a graphene layer is suspended over a silicon substrate by a layer of an insulating material. Adjusting the voltage across the graphene layer and the silicon substrate induces strain in the graphene layer by electrostatic attraction.