On-Chip Ultrafast Plasmonic Graphene Hot Electron Bolometric Photodetector

We investigate a waveguide-integrated plasmonic graphene photodetector operating based on the hot carrier photo-bolometric effect, which is characterized simultaneously by high responsivity on the scale of hundreds of A/W and high speed on the scale of 100's of GHz that is limited only by the product of the electronic heat capacitance and thermal resistance. We develop a theory of the bolometric effect originating from the band nonparabolicity of graphene and estimate responsivity due to the bolometric effect, which is shown to significantly surpass the responsivity of the coexisting photoconductive effect, thus convincingly demonstrating the dominance of the bolometric effect. Based on the theory, we propose a novel detector configuration based on a hybrid waveguide that allows for efficient absorption in graphene over a short distance and subsequently a large change of conductivity. The results demonstrate the potential of graphene for high-speed communication systems.