Strain compensated InGaAs/InGaP quantum well infrared detector for midwavelength band detection

A high detectivity multiquantum well midinfrared photodetector is reported. It is based on a strain compensated InGaAs/InGaP on InP structure, using bound-to-continuum intersubband absorption, with λ_P=4.9μm and ∼0.5 μm full width at half maximum. This design is unique by enabling a large critical thickness, thus increasing the quantum efficiency. Photodetectors with background-limited performance (BLIP) with detectivity of D_λ^*(BLIP)=3.2×10¹⁰cm Hz /W up to 110 K, with only ten quantum well periods were implemented. Arguments are given to predict an optimized background-limited performance for this design up to 135 K.