Photovoltaic quantum well infrared detector

Abstract
A photovoltaic infrared detector based on photoemission from a single modulation doped GaAs-AlGaAs quantum well is presented. The modulation doping provides a built-in field which allows unbiased operation. We show results from a device which is sensitive to 180 meV (7 μm wavelength) light, with a bandwidth of 20 meV, for which we estimate the quantum efficiency to be 1%. We demonstrate that the detector may be tuned to different wavelengths by varying the width of the well.