Optimal absorber thickness in long-wave multiple-stage detector

The detectivity characteristics of interband cascade infrared type-II superlattice detectors for long-wave infrared detection ( λ cut - off  = 8 μm at room temperature) are discussed. We present comparison of two superlattices: InAs/GaSb and InAs/InAsSb, assuming the characteristic parameters—absorp...

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Bibliographic Details
Published in:Optical and quantum electronics 2019-02, Vol.51 (2), p.1-6, Article 57
Main Authors: Hackiewicz, Klaudia, Martyniuk, Piotr, Rutkowski, Jarosław
Format: Article
Language:English
Subjects:
Absorbers
ABSORPTION
Absorptivity
CARRIER LIFETIME
CARRIERS
Characterization and Evaluation of Materials
Computer Communication Networks
Dependence
DETECTION
DIFFUSION LENGTH
Electrical Engineering
ENGINEERING
GALLIUM ANTIMONIDES
INDIUM ARSENIDES
Infrared detectors
Lasers
Mathematical analysis
NOISE
Optical Devices
Optics
Photonics
Physics
Physics and Astronomy
Sensors
SUPERLATTICES
TEMPERATURE RANGE 0273-0400 K
THICKNESS
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Summary:The detectivity characteristics of interband cascade infrared type-II superlattice detectors for long-wave infrared detection ( λ cut - off  = 8 μm at room temperature) are discussed. We present comparison of two superlattices: InAs/GaSb and InAs/InAsSb, assuming the characteristic parameters—absorption coefficients α and carrier lifetimes τ published in literature. Dependence of the Johnson-noise limited detectivity on the absorber thickness for a different number of stages is reported. Higher detectivity D * value can be achieved by increasing the carrier lifetime. However, for detectors based on type-II InAs/GaSb superlattice increasing the carrier lifetime up to 25 ns leads to a situation in which one stage is preferred, i.e. for detector with a single absorber, we obtain the highest detectivity value. In the case of InAs/InAsSb material, the situation is similar for τ  ≥ 80 ns. We have shown that the optimal absorber thickness at which the highest detectivity values are obtained depends not only on the absorption coefficient α and the number of stages N S , but also on the carrier diffusion length L . According to a calculations, cascade detectors based on Ga-free material should have much higher optimal absorber thicknesses than materials based on InAs/GaSb.
ISSN:0306-8919
1572-817X
DOI:10.1007/s11082-019-1771-6