Two-color GaAs/-AlGa-As quantum well infrared detector with voltage-tunable spectral sensitivity at 3-5 and 8-12 mym.

We report on a novel GaAs:Si/(AlGa)As multiquantum well photodetector structure which exhibits photoresponse maxima in both the 8 - 12 and 3 - 5 Mym spectral regions. The relative intensity of these maxima strongly depends on the bias voltage, demonstrating the potential of such a structure as a tunable two-color intersubband detector.