Microcavity enhances photoresponse of graphene

Photodetectors convert light into electrical signals and are widely used as receivers in fiber optic networks, converting light information to the form of an electric signal. Though they are usually fabricated from semiconductors such as silicon or gallium arsenide, by using graphene researchers make use of the internal electric field that exists at the interface of graphene and metal. However, the low optical absorption of graphene leads to a low responsivity of these devices. Researchers are searching for different approaches to increase the interaction length of light with graphene and to enhance the optical absorption. One novel approach, developed by scientists at Vienna University of Technology in Austria, is based on the integration of graphene into an optical microcavity. The increased electric field amplitude inside the cavity causes more energy to be absorbed. This in turns leads to a significant increase in photoresponse.