High-frequency very long wave infrared quantum cascade detectors

High speed quantum cascade detectors (QCDs) in a very long wave infrared range have been fabricated and characterized. Based on the resonant longitudinal optical-phonon scattering extraction relaxation mechanism, the QCD material behaves at an intrinsically high speed. In order to achieve high speed operation, we integrated microwave technology into the device process to reduce the parasitic parameters and ensure a low time constant of the effective resistance, ilnductance, capacitance (RLC) circuit. The peak response is located at 14.2 mu m at 77 K. The electrical response characteristics of these QCDs was tested using a microwave rectification technique. The -3 dB cutoff frequency of a 100 x 100 mu m(2) QCD is 3.2 GHz. The cutoff behavior of our devices were modeled with a second order filter RLC circuit model and showed good agreement with the experimental data.