Detector material and sensitivity analysis for space-based infrared sensors

The ultimate detection performance of HgCdTe, quantum well (QW) and extrinsic Si detectors under low temperatures is analyzed. The theoretical limits of the internal photon response for the three detectors are compared. The materials of space-based detectors in space tracking and surveillance system (STSS) are discussed. The results show that among three detectors, the best performance can be obtained from HgCdTe detectors under 40 K in the mid-long wave infrared (MLWIR) and long wave infrared (LWIR) spectral regions. Its ultimate detectivity in the MLWIR spectral region, with a cutoff wavelength of 8 μm, is on the order of 1×1018 cm·Hz1/2/W. And that in the LWIR spectral region, with cutoff wavelengths of 12 μm, 16 μm and 20 μm, is on the order of 1×1015 cm·Hz1/2/W, 1×1014 cm·Hz1/2/W and 1×1013 cm·Hz1/2/W, respectively.