nBn-Photodiode Based on InAsSb/AlAsSb Alloys with a Long-Wavelength Cutoff of 5 μm

The results of studying the photoelectric characteristics of an nBn structure are presented. The photodiodes based on such structures may have a cutoff wavelength as high as 5 μm. Calculations based on these results show that such photodiodes have a threshold photosensitivity comparable with that of traditional analogs. An energy band diagram of the nBn structure is proposed based on experimental results and theoretical estimations; this diagram makes it possible to estimate the effect of potential barriers in the valence band of the wide-gap layer and at its boundaries with narrow-gap layers on the nBn-based photodiode sensitivity. The experimental results of studying the dependence of the photocurrent thermal-activation energy on the photodiode bias turned out to be important for developing the model.