  Semimetals are being explored for their unique advantages in low-energy
high-speed photodetection, although they suffer from serious drawbacks such as
an intrinsically high dark current. In this perspective, we envision the
exploitation of topological effects in the photoresponse of these materials as
a promising route to circumvent these problems. We overview recent studies on
photodetection based on graphene and other semimetals, and further discuss the
exciting opportunities created by the topological effects, along with the
additional requirements that they impose on photodetector designs.
