Photodetection mechanisms in floating gate photoconductors with far-infrared quantum well intersubband transitions

We present two mechanisms of far-infrared detection using a GaAs/AlGaAs double-quantum well floating-gate heterostructure The conductance of a well region is modulated by photoionized electrons that either tunnel into an underlying transistor channel, or are trapped by DX centres. We report responsivities of 100 A/W and 160 A/J, and operating temperatures of up to 30 K and 100 K, respectively.