Noise characteristics of quantum-well infrared photodetectors at low temperatures

Abstract

In this work, we have performed high-sensitivity measurements on the dark current and the noise current of infrared hot-electron transistors (IHETs) and their constituent quantum-well infrared photodetectors (QWIPs) at 4.2 K. We found that the dominant noise of the QWIPs in this regime is not from the expected shot noise but from the 1/f noise and possibly a bias-independent noise. Part of the 1/f noise is unrelated to impurities in the barrier and is intrinsic to the sequential tunneling mechanism in QWIPs. By filtering out the impurity-assisted tunneling current, the IHETs reduce the dark current and the 1/f noise, and improve the detector sensitivity and uniformity.