11 November 2002 Scaling law for responsivity roll-off in quantum-well infrared photodetectors under low-temperature and low-irradiance conditions
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Abstract
The peak responsivity of quantum-well infrared photodetectors (QWIPs) is known to decrease or "roll-off" to a lower plateau value as the frequency of an incoming time-varying photon irradiance increases. The time constant associated with the roll-off frequency depends on the amplitude of the applied DC bias, the incoming irradiance, and the device temperature. In this paper we demonstrate the scaling law for the responsivity roll-off and use it to estimate the quantum-well capacitance by first measuring the roll-off frequency as a function of bias and optical flux and then measuring the device dynamic resistance under similar conditions. The slope of the scatter plot of the roll-off angular frequency versus the inverse dynamic resistance is related to the quantum-well capacitance. Using this approach, we estimate the quantum-well capacitance in a fifty-well, Al0.3Ga0.7As/GaAs QWIP pixel of area 2.44 x 10-4 cm-2 to be ~ 1.22pF at 50 K.
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Dang T. Le, Christian P. Morath, Dan Hong Huang, Hillary E. Norton, David A. Cardimona, "Scaling law for responsivity roll-off in quantum-well infrared photodetectors under low-temperature and low-irradiance conditions", Proc. SPIE 4823, Photonics for Space Environments VIII, (11 November 2002); doi: 10.1117/12.453516; https://doi.org/10.1117/12.453516
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KEYWORDS
Quantum well infrared photodetectors

Capacitance

Resistance

Quantum wells

Sensors

Optical amplifiers

Temperature metrology

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