Demonstration of the Longwave Type-II Superlattice InAs/InAsSb Cascade Photodetector for High Operating Temperature
Waldemar Gawron, Łukasz Kubiszyn, Krystian Michalczewski, J. Piotrowski, Piotr Martyniuk
Abstract
This letter presents InAs <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$/$ </tex-math></inline-formula> InAsSb-based superlattice (SL) long wavelength (8– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$12 \mu \text{m}$ </tex-math></inline-formula> ) range (LWIR) cascade photodetector operating at temperatures > 190 K. The design of the detector resolves the problem of the low quantum efficiency ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">QE</i> ) 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$/$ </tex-math></inline-formula> InAsSb superlattice (T2SLs) absorbers. The constituent stages of the cascade are connected by the low resistance tunnel junctions. Detectivity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D^{\ast }$ </tex-math></inline-formula> ) of the unbiased device reaches ~ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.7\,\,\times10$ </tex-math></inline-formula> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> cmHz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{1/2} /\text{W}$ </tex-math></inline-formula> at 210 K, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> = <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10 \mu \text{m}$ </tex-math></inline-formula> .