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 $
=
$10 \mu \text{m}$
.