A resonant-cavity-enhanced type-II superlattice (T2SL) infrared
detector based on a metal grating has been designed to address the
weak photon capture and low quantum efficiency (QE) issues of T2SL
infrared detectors. Simulations have been conducted to analyze the
effects of metal grating parameters, including length, thickness, and
incident angle, on the spectral response and absorptivity of the
absorption layers in T2SL infrared detectors. By optimizing the
design, an appropriate resonant cavity structure was obtained.
Research results indicate that the resonant cavity structure can
significantly enhance the absorption rate of a T2SL infrared detector
with a 0.2 µm thick absorption layer in the 3–5 µm
wavelength range, observing peak absorption rates at 3.82 µm
and 4.73 µm, with values of 97.6% and 98.2%, respectively. The
absorption rate of the 0.2 µm thick T2SL absorption layer at
peak wavelengths increased from 6.03% and 2.3% to 54.48% and 27.91%,
respectively. The implementation of the resonant-cavity-enhanced T2SL
infrared detector improves the QE while reducing absorption layer
thickness, thus opening up new avenues for improving T2SL detector
performance.