7 February 2017 Extended wavelength infrared photodetectors
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Extension of the wavelength threshold of an infrared detector beyond λ t = h c / 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 λ t = 3.1    μ m , was shown to have an extended threshold of 45    μ m at 5.3 K, at zero bias. Under negative and positive applied bias, this range was further extended to 60 and 68    μ m , 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    μ m .
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Dilip Chauhan, Dilip Chauhan, A. G. Unil Perera, A. G. Unil Perera, Lianhe Li, Lianhe Li, Li Chen, Li Chen, Suraj P. Khanna, Suraj P. Khanna, Edmund H. Linfield, Edmund H. Linfield, } "Extended wavelength infrared photodetectors," Optical Engineering 56(9), 091605 (7 February 2017). https://doi.org/10.1117/1.OE.56.9.091605 . Submission: Received: 16 December 2016; Accepted: 25 January 2017
Received: 16 December 2016; Accepted: 25 January 2017; Published: 7 February 2017


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