VOLTAGE TUNABLE 3-COLOR QUANTUM-WELL INFRARED PHOTODETECTOR

A voltage tunable three-color quantum well infrared photodetector (QWI P) consisting of asymmetric GaAs/AlGaAs double quantum wells has been demonstrated. The detector uses electron intersubband transitions in a coupled asymmetric double quantum well superlattice. The infrared pho tocurrent spectrum characterized using a blackbody monochromator sourc e shows three prominent peaks appearing at 8.4 mum, 9.6 mum, and 10.3 mum under different biases. The three detection peaks are well resolve d and can be independently selected by tuning the applied voltage. The responsivity and the detectivity of the detector at different biases and operating temperatures are characterized and found to be sufficien t for detector operation at temperatures approximately 60 K.