InP-Based Broadband Photodetectors With InGaAs/GaAsSb Type-II Superlattice

In this work, an In_0.53Ga_0.47As/GaAs_0.5Sb_0.5 type-II superlattice(T2SL) based broadband photodetector with an optical spectrum response ranging from 250 nm to 2400 nm is demonstrated. The photodetector shows a low dark current density of $3.48\times 10^{-4}$ A/cm² under the bias of −1 V and a specific detectivity (D*) of $1.59\times 10^{10}$ cm $\cdot $ Hz1/2/W at $2 ~\mu \text{m}$ at 293 K. A recessed window on the surface of the top P layer was fabricated to enhance the responsivity of ultraviolet (UV) and visible band. The UV and visible band quantum efficiency (QE) can increase by 40% with the recessed window.