1 October 2000 Nonlinear response of quantum well infrared photodetectors under low-background and low-temperature conditions
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Quantum well IR photodetectors (QWIPs) have been proposed for use in space-based sensing applications. These space systems place stringent performance requirements on IR detectors due to low-irradiance environments and the associated requirement for low- temperature operation. We demonstrate that under these conditions, the responsivity of a QWIP detector depends on frequency and that the shape of the frequency response varies with operational conditions. This nonlinear frequency response is empirically similar to dielectric relaxation effects observed in bulk extrinsic silicon and germanium photoconductors under similar operational conditions. Radiometric characterization data demonstrate how the frequency response varies with temperature, photon irradiance, and bias voltage. These data also show that at low irradiances and temperatures, the detector response is extremely slow, with response times on the order of seconds. The performance of the QWIP detector is described using standard figures of merit including responsivity, noise, and specific detectivity (D*). We also describe the performance of an IR focal plane array (IRFPA) made with QWIP detectors, under operational conditions that result in long response times. The dependence of this time constant on photon irradi- ance and operating temperature is also described.
John Edward Hubbs, John Edward Hubbs, Douglas C. Arrington, Douglas C. Arrington, Mark E. Gramer, Mark E. Gramer, Gary A. Dole, Gary A. Dole, } "Nonlinear response of quantum well infrared photodetectors under low-background and low-temperature conditions," Optical Engineering 39(10), (1 October 2000). https://doi.org/10.1117/1.1308491 . Submission:

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