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Proceedings Paper

Resonant cavity enhanced photodetectors for the mid-wave infrared
Author(s): A. P. Craig; T. Golding; G. R. Savich; G. W. Wicks; A. R. Marshall
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Paper Abstract

We present III-Sb resonant cavity-enhanced (RCE) photodetectors suitable for gas detection in the mid-wave infrared. AlAsSb/GaSb DBRs and absorbers of bulk InAsSb or a type-II InAsSb-InAs SLS were grown on GaSb, allowing for operation at 3.72 μm or 4.52 μm, with linewidth Δλ < 50 nm and Δλ < 70 nm, respectively. A barrier diode structure was used, and the absorber thickness was limited to 96 nm for InAsSb – or 192 nm for the SLS – in order to limit the dark currents. High quantum efficiency was obtained through the resonant optical field, while the remainder of the cavity was grown using wide-gap AlAsSb spacer layers not contributing to the dark current. By carefully compensation doping the AlAsSb layers, the 3.72 μm device was bandgap-engineered for a flat Fermi level in the thin absorber, and hence dark currents which scale with the absorber thickness. This can equate to a >20x reduction in noise compared with a conventional nBn detector with full thickness absorber. At 3.72 μm, performance above the BLIP limit imposed on broadband photodetectors was found by calculating for the specific detectivity.

Paper Details

Date Published: 16 October 2019
PDF: 6 pages
Proc. SPIE 11163, Emerging Imaging and Sensing Technologies for Security and Defence IV, 1116309 (16 October 2019); doi: 10.1117/12.2536900
Show Author Affiliations
A. P. Craig, Lancaster Univ. (United Kingdom)
T. Golding, Amethyst Research Ltd. (United Kingdom)
Amethyst Research Inc. (United States)
G. R. Savich, Amethyst Research Inc. (United States)
G. W. Wicks, Amethyst Research Inc. (United States)
The Institute of Optics, Univ. of Rochester (United States)
A. R. Marshall, Lancaster Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 11163:
Emerging Imaging and Sensing Technologies for Security and Defence IV
Gerald S. Buller; Richard C. Hollins; Robert A. Lamb; Martin Laurenzis, Editor(s)

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