Advances in III-V Semiconductor Unipolar Barrier Infrared Photodetectors*

The past decade has seen accelerated progress in III-V semiconductor infrared photodetector technology. The advent of the unipolar barrier infrared detector device architecture has in many instances greatly alleviated generation-recombination (G-R) and surface-leakage dark current issues that had been problematic for many III-V photodiodes. Meanwhile advances in a variety type-II superlattices (T2SLs) such as InGaAs/GaAsSb, InAs/GaSb, and InAs/InAsSb, as well as in bulk III-V material such as InGaAsSb and metamorphic InAsSb, have provided continuously adjustable cutoff wavelength coverage from the short wavelength infrared (SWIR) to the very long wavelength infrared (VLWIR). The confluence of these developments has led to a new generation of versatile, cost-effective, high-performance infrared detectors and focal plane arrays (FPAs) based on robust III-V semiconductors, providing a viable alternative to HgCdTe (MCT). In particular, InAs/InAsSb T2SL detectors has enabled FPAs with significantly higher operating temperature than the market-leading mid-wavelength infrared (MWIR) InSb FPAs.