MQW Based Blocked Intersubband Detector for Low-Background Operation

Multiple-quantum-well (MQW) AlxGa1-xAs/GaAs infrared photodetectors that are better suited [relative to prior AlxGa1-xAs/GaAs quantum-well infrared photodetectors (QWIPs)] for operation under low-background conditions are undergoing development. These devices are expected to function at a temperature of 30 K without nonlinear effects or delayed responses. Even at this low temperature, the readout electronic circuits for imaging arrays of these photodetectors are expected to work smoothly — that is, with no freezeout of charge carriers. Large focal-plane arrays of these detectors should be relatively inexpensive because they could be fabricated by use of mature techniques for the growth and processing of AlxGa1-xAs/GaAs.