A type-II superlattice period with a modified InAs to GaSb thickness ratio for midwavelength infrared photodiode performance improvement
Résumé
We present a type-II superlattice period with a modified InAs to GaSb thickness ratio for midinfrared detection. In this kind of structure, the large electron-hole wave-function overlap and the low intrinsic carrier concentration lead to a significant signal-to-noise ratio enhancement. For the proof of concept, a sample designed with an InAs to GaSb thickness ratio close to 2 was grown. Comparison with standard design photodiodes shows an improvement of the differential resistance area product by one and a half decade while the quantum efficiency was more than doubled.