Extended wavelength infrared photodetectors

Extension of the wavelength threshold of an infrared detector beyond λt=hc/Δ is demonstrated, without reducing the minimum energy gap (Δ) of the material. Specifically, a photodetector designed with Δ=0.40  eV, and a corresponding λt=3.1  μm, was shown to have an extended threshold of ∼45  μm at 5.3...

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Bibliographic Details
Published in:Optical engineering 2017-09, Vol.56 (9), p.091605-091605
Main Authors: Chauhan, Dilip, Perera, A. G. Unil, Li, Lianhe, Chen, Li, Khanna, Suraj P, Linfield, Edmund H
Format: Article
Language:English
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Summary:Extension of the wavelength threshold of an infrared detector beyond λt=hc/Δ is demonstrated, without reducing the minimum energy gap (Δ) of the material. Specifically, a photodetector designed with Δ=0.40  eV, and a corresponding λt=3.1  μm, was shown to have an extended threshold of ∼45  μm at 5.3 K, at zero bias. Under negative and positive applied bias, this range was further extended to ∼60 and ∼68  μm, respectively, with the photoresponse becoming stronger at increased biases, but the spectral threshold remained relatively constant. The observed wavelength extension arises from an offset between the two potential barriers in the device. Without the offset, another detector with Δ=0.30  eV showed a photoresponse with the expected wavelength threshold of ∼4  μm.
ISSN:0091-3286
1560-2303
DOI:10.1117/1.OE.56.9.091605