Design of uni-traveling-carrier photodiode With Nanoscale Optical Microstructures

In this article, we report a uni-traveling-carrier photodiode (UTC-PD) incorporating nanoscale optical microstructures. We design a waveguide-based UTC-PD containing an internal optical scattering structure to convert incident light from vertical incidence to lateral propagation and to constrain the light within the absorption layer of the UTC-PD as much as possible. In this way, the proposed UTC-PD can have an operating performance like that of a waveguide-type PD under vertical light incidence, and its responsivity will increase. The ideal responsivity of the designed UTC-PD with an absorption layer thickness of 200nm after optimization can reach 0.43A/W, which is 48% higher than that of the traditional structure.