High quality InAsSb-based heterostructure n-i-p mid-wavelength infrared photodiode

We present the effect of interface quality on the performance of InAsSb based hetero n-i-p middle wavelength infrared (MWIR) photodiodes. By adopting heavily doping wide bandgap p- and n-type layers and inserting a thin layer between the two doped layers and the absorbing InAsSb region, the interface quality can be improved. We also employed proper fabrication processes in device fabrication to improve surface quality. It is found that the improved interface and surface quality can reduce the noise current and enhance detection performance. A detectivity of ∼1.5 × 109 cmHz1/2W−1 can be achieved at room temperature, and it can be increased to ∼4.0 × 109 cmHz1/2W−1 at 250 K.