Voltage-controlled tunable GaAs/AlGaAs multistack quantum well infrared detector

We describe a new type of intersubband GaAs/AlGaAs infrared detector consisting of three stacks of quantum wells; the quantum wells in a given stack are identical, but are different from stack to stack. Each stack is designed to yield an absorption and a photoresponse at a different peak wavelength. The resulting device is an infrared detector which can operate in a number of modes. Among the features of this device are a wide-band detection domain, a tunable response and excellent responsivities and noise figures. The tunable operation includes a sharp peak-switching response which follows the formation, expansion, and readjustment of electric field domains within the multiquantum well region.