Investigation of the Spectral Response of nBn Photodiodes Based on InAsSb

Abstract

The classical structure of nBn photodiode based on InAsSb for the detection in the mid-wave infrared (MWIR) range is considered. The optical absorption in the heterostructure at any position is calculated with allowance for the features of absorption of the InAsSb active layer, in particular, the Burstein–Moss effect and the Urbach rule. The quantum efficiency and spectral response of the sensitivity are calculated taking into account multiple reflections at the interfaces of the heterostructure and the features of free-carrier absorption in the GaSb substrate. The optimal thickness of the active layer of the nBn photodiode is determined for various lifetimes of minority carriers. Relatively high BLIP detectivity of the FPA is shown.