MULTICOLOR VOLTAGE-TUNABLE QUANTUM-WELL INFRARED PHOTODETECTOR

A novel concept of a quantum-well infrared photodetector (QWIP) with i ts spectral response peak tunable by an external voltage is described and tested experimentally. This multicolor detector structure is made by stacking conventional (one-color) QWIP's, separated by thin, heavil y doped layers (almost-equal-to 90 nm in our test structure). The most important feature is that external applied dc voltage is distributed among the different one-color QWIP's according to their dc resistances . Each one-color QWIP therefore turns on sequentially in the order det ermined by its resistance.