Improved Efficiency-Bandwidth Product of Modified Uni-Traveling Carrier Photodiode Structures Using an Undoped Photo-Absorption Layer

Abstract

Effects of undoped photo-absorption layers in modified uni-traveling carrier photodiode structures on quantum efficiency and bandwidth are reported. Modified uni-traveling carrier photodiode structures having different undoped photo-absorption layer thicknesses were fabricated and characterized. Efficiency and bandwidth of photodiodes having an optimized undoped photo-absorption layer were larger than those of photodiodes without such a layer, which agrees well with the theoretical analysis of the dynamic behavior of the photodiodes using drift-diffusion model. The results indicate that both the quantum efficiency and bandwidth of the uni-traveling carrier photodiode structures can be extended by incorporating an optimized thickness of undoped photo-absorption layer.