Provided is a photodetector including a substrate, a first doped region on the substrate, a second doped region having a ring structure, wherein the second doped region is provided in the substrate, surrounds the first doped region and is horizontally spaced apart from a side of the first doped region, an optical absorption layer on the first doped region, a contact layer on the optical absorption layer, a first electrode on the contact layer, and a second electrode on the second doped region.