Demonstration of InAlSb MWIR Detector for High Operation Temperature Application

This paper reports the growth and characterization of InAlSb photodiodes grown on a InSb substrate for high operation temperature application. The studied InAlSb structures cover a cutoff wavelength range from 4.4 μm to 4.8 μm by tuning the Al composition in the absorber layers. A high Al composition barrier layer was inserted between the P-type contact layer and the absorber layer to reduce leakage current from the contact layer. To study the potential for high operation temperature device application, we here consider a 4.5 μm cutoff InAlSb p–i–n photodetector as an example. The detector exhibited a differential resistance at zero bias R0A in excess of 3.8 × 104 Ωcm2 and a quantum efficiency of 57% at 110 K, providing a specific detectivity of more than 1.5 × 1011 cmHz1/2/W and a background limited operating temperature of 130 K with a 300 K background. The dominant mechanism of dark current and its relationship with operating temperature were analyzed in detail. InAlSb detectors are potentially low-cost, have high operating temperature, low dark current and a high quantum efficiency, which can meet the demands of high performance infrared detectors for small platforms.