PHOTOVOLTAIC QUANTUM-WELL INTERSUBBAND INFRARED DETECTORS BY INTERNAL ELECTRIC-FIELDS

We report on quantum well (QW) intersubband infrared detectors which demonstrate a resistive photovoltaic effect, i. e., a steady state photocurrent without external bias voltage. Detection relies on a transport mechanism in which the motion of the photoexcited carriers is rectified by built-in electric fields in the barrier layers. This mechanism is demonstrated using asymmetrically doped double-barrier quantum well detectors designed for the 3-5 mu m-regime. We also propose a novel detector structure for photovoltaic QW intersubband detection in the 8 - 12 mu m-regime.