High-Performance Bias-selectable Dual-band Short-/Mid-wavelength Infrared Photodetectors and Focal Plane Arrays based on InAs/GaSb/AlSb Type-Ⅱ Superlattices

摘要

We report a bias selectable dual-band Type-II superlattice-based short-wave infrared (SWIR) and mid-wave infrared (MWIR) co-located photodetector capable of active and passive imaging. A new double-layer etch-stop scheme is introduced for back-side-illuminated photodetectors, which enhanced the external quantum efficiency both in the SWIR and MWIR spectral regions. Temperature-dependent dark current measurements of pixel-sized 27 urn detectors found the dark current density to be ～1×10~(-5) A/cm~2 for the ～4.2 μm cut-off MWIR channel at 140 K. This corresponded to a reasonable imager noise equivalent difference in temperature of ～49 mK using F/2.3 optics and a 10 ms integration time (tint), which lowered to ～13 mK at 110 K using and integration time of 30 ms, illustrating the potential for high-temperature operation. The SWIR channel was found to be limited by readout noise below 150 K. An excellent imagery from the dual-band imager exemplifying pixel coincidence is shown.