2.7 mu m quantum cascade detector: Above band gap energy intersubband detection

Quantum cascade detectors (QCDs) are mid-infrared and far-infrared, low-noise, photovoltaic detectors utilizing intersubband transitions. This Letter presents an InAs/AlAs0.16Sb0.84 based QCD lattice matched to an InAs substrate. This material system exhibits properties like a low effective electron mass of the well material of 0.023 m(0), beneficial for higher optical absorption strength, and a high conduction band offset of 2.1 eV, allowing the design of QCDs in the mid-infrared and near-infrared region. The presented QCD has a peak spectral response at 2.7 mu m (0.459 eV), the center of a CO2 absorption band. To enable top side illumination, a grating was implemented. This additionally bypasses absorption by the narrow bandgap 0.345 eV (3.54 mu m) InAs substrate material. The QCD has a peak responsivity at a room temperature of 5.63 mA/W and a peak specific detectivity of 1.14 x 10(8) Jones. (c) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).