Infrared Photodetector Features No Dark Current

Researchers at Thales Research and Technology in Orsay, France, and at Université Paris 7 have reported the development of an infrared detector based on the generation of an electronic displacement through a cascade of quantum levels. Called a quantum cascade detector, the device requires no applied bias voltage to operate and therefore displays no dark current. They reported on the detector, which may have applications in small-pixel, large-area focal plane arrays, in the Oct. 4 issue of Applied Physics Letters.

The detector features 40 layers of seven GaAs quantum wells and AlGaAs barriers, sandwiched between Si-doped contact layers. Experiments with a 100 3 100-µm device at 50 K revealed a responsivity of 35 mA/W at a wavelength of 9.2 µm. The integrated quantum efficiency was on the order of a quantum-well infrared photodetector.