Multiple-color GaAs/AlGaAs superlattice infrared photodetector controlled by the polarity and magnitude of the bias voltage

We present a voltage-controlled multi-color infrared photodetector consisting of two stacks of GaAs/AlGaAs superlattices with main absorption peaks at 10.7 /spl mu/m and 6.7 /spl mu/m respectively. The switching in response wavelengths is achieved by using the opposite polarity dependence of responsivity in each stack. Compared with traditional voltage-controlled designs, the detector achieves better switching in response colors and lower operating bias voltage.