Demonstration of the Longwave Type-II Superlattice InAs/InAsSb Cascade Photodetector for High Operating Temperature

This letter presents InAs / InAsSb-based superlattice (SL) long wavelength (8- 12 \mu \text{m} ) range (LWIR) cascade photodetector operating at temperatures > 190 K. The design of the detector resolves the problem of the low quantum efficiency ( QE ) and resistance of the traditional photovoltaic detectors optimized for high temperature (HOT) conditions. The device was deposited by molecular beam epitaxy (MBE) on GaAs substrates with type-II InAs / InAsSb superlattice (T2SLs) absorbers. The constituent stages of the cascade are connected by the low resistance tunnel junctions. Detectivity ( D^{\ast } ) of the unbiased device reaches ~ 6.7\,\,\times10 8 cmHz ^{1/2} /\text{W} at 210 K, \lambda = 10 \mu \text{m} .