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In this paper, we give an overview of quantum cascade detector technology for the near- and mid-infrared wavelength range. Thanks to their photovoltaic operating principle, the most advanced quantum cascade detectors offer great opportunities in terms of high detection speed, reliable room temperature operation, and excellent Johnson noise limited detectivity. Besides some important features dealing with their fabrication and their general characteristics, we will also briefly present some possibilities for performance improvement. Elementary theoretical considerations adopted from photoconductive detectors confirm that optimization of such devices always involves various trade-offs. [ABSTRACT FROM AUTHOR]

The authors report on short-wavelength In0.53Ga0.47As/AlAs0.56Sb0.44 quantum cascade detectors (QCDs). At room temperature, one device detects at 505 meV (2.46 μm) with a responsivity of 2.57 mA/W, while a second QCD is sensitive at 580 meV (2.14 μm) with a responsivity of 0.32 mA/W. [ABSTRACT FROM AUTHOR]

We report on intersubband absorption, photovoltaic, and photoconductive detection of near-infrared radiation in regular AlN/GaN superlattice structures. Photoconductive detection was achieved up to temperatures of 120 K. Simulation of the transition energies using a self-consistent Schrödinger-Poisson equation solver for our specific well width is in good agreement with the measurements. For a well width of 17 Å, the transition energy between ground state and first excited state in the GaN well is around 6300 cm-1 which corresponds to 1.6 μm. [ABSTRACT FROM AUTHOR]