Pixelless imaging by transmissive quantum-well infrared photodetectors integrated with light emitting diodes

Summary form only given. The maturity of III-V materials in terms of growth and microfabrication has been a strong incentive for the development of III-V based infrared focal plane arrays (FPA). Quantum-well infrared photodetectors (QWIP) are proposed commercially and today, the efforts shift towards multicolor applications. The QWIP FPA technology is based on the conventional hybridization of a pixellated QWIP to a Si readout circuit. To circumvent the hybridization we are exploring a different approach that consists in reading the photocurrent map optically. We have proposed to put, during the epitaxial growth, a QWIP stack in series with a near-infrared light emitting diode (LED). In 1995, single QWIP-LED up-conversion elements have been demonstrated and, in 1997, large area, un-pixellated devices have demonstrated the up-conversion of far-infrared scenes to near-infrared images which are read by Si CCD arrays. Since then, the image transfer quality has been improved and new designs have been discussed.