Investigation of InGaAsSb-based heterojunction photodiodes for extended SWIR imaging

A. Wörl; R. Müller; V. Daumer; J. Niemasz; F. Rutz; R. Rehm

doi:10.1117/12.2680004

23 October 2023 Investigation of InGaAsSb-based heterojunction photodiodes for extended SWIR imaging

A. Wörl, R. Müller, V. Daumer, J. Niemasz, F. Rutz, R. Rehm

Proceedings Volume 12737, Electro-Optical and Infrared Systems: Technology and Applications XX; 1273707 (2023) https://doi.org/10.1117/12.2680004
Event: SPIE Security + Defence, 2023, Amsterdam, Netherlands

Abstract

The detection in short wavelength infrared (SWIR) band, ranging from 1–3 μm, provides a wide range of applications in earth observation, plastics recycling, biology and hyperspectral imaging, gas analysis and defense. In this paper, uncooled InGaAsSb-based detectors for the wavelength range beyond 1.7 μm, the extended SWIR (eSWIR), are investigated for the later use in a thermographic traffic monitoring system that is supposed to localize potentially dangerous overheated hot-spot regions. Up to the wavelength of 1.7 μm, InGaAs lattice-matched with InP is used for photodetection in the SWIR. To reach a longer cutoff wavelength, “extended InGaAs” can be employed. This requires strained growth that leads to more growth defects and reduced yield, though. InGaAsSb, however, provides a tunable bandgap for detection beyond 1.7 μm and still enables lattice-matched growth on GaSb, which makes it a viable alternative for photodetection in the eSWIR. We have demonstrated that the bandgap of InGaAsSb can be tuned in the eSWIR by modifying the stoichiometry for lattice-matched growth on GaSb. Furthermore, we have successfully realized InGaAsSb heterojunction photodiodes with an AlGaAsSb hole barrier. At room temperature, the diodes achieve a dark current density of 0.5 mA/cm² and a responsivity better than 1 A/W resulting in an excellent peak detectivity of 9 x 10¹⁰ cm Hz^1/2/W. Thus, the highperformance detector arrays operating at room temperature are within reach in order to meet application demands.

Conference Presentation

Citation Download Citation

A. Wörl, R. Müller, V. Daumer, J. Niemasz, F. Rutz, and R. Rehm "Investigation of InGaAsSb-based heterojunction photodiodes for extended SWIR imaging", Proc. SPIE 12737, Electro-Optical and Infrared Systems: Technology and Applications XX, 1273707 (23 October 2023); https://doi.org/10.1117/12.2680004

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