<title>Temperature dependence of quantum well infrared photodetector focal plane array characteristics</title>

Abstract

We investigated the operation temperature dependence of the characteristics of quantum-well infrared photodetector focal plane arrays (QWIP-FPAs) for the 8 - 10 micrometer wavelength region from 65 K to 80 K. We found that a proposed simple circuit model explains the temperature dependence of the DC output and signal intensity of the QWIP-FPA. In this model, we used empirical current-voltage (I-V) characteristics of the QWIP, which was not hybridized with the readout integrated circuit (called 'QWIP itself'), measured at various temperatures and a simplified equivalent circuit model. The signal intensity of the QWIP-FPAs decreases as the temperature increases, while the photo-current of the QWIP itself increases slightly as the temperature increases. The difference between these behaviors is because the bias applied to QWIP in QWIP-FPA varies during the integration cycle and the bias applied to QWIP itself is constant. The noise equivalent temperature difference (NETD) increases from 0.10 K to 0.20 K as the operation temperature increases from 65 K to 80 K, since the signal intensity decreases and the shot noise increases with increasing the dark current.