ACS Photon. https://doi.org/cx9z (2018)

Ping Ma, Yannick Salamin and colleagues at ETH Zurich, Switzerland have demonstrated a waveguide-integrated graphene photodetector that is both fast and responsive. The device uses a 6-μm-long layer of graphene with a series of bowtie metallic structures to enable plasmonically enhanced absorption, resulting in a device with an external responsivity of 0.5 A W–1 and a photoresponse of up to 110 GHz. The device’s improved performance is a result of several factors. First, there is the enhancement at the interface of the metal and dielectric, typical for surface plasmons. Second, the structure also features tapered gaps between the metallic halves of each nanostructure, which focuses two-dimensionally localized gap plasmons. Finally, the structures have a bowtie shape with a narrow central gap between the entry and exit tapers.

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American Chemical Society