Broadband cavity architecture for ultra-thin type-II superlattice mid-infrared detectors

Abstract

A broadband cavity architecture for ultra-thin type-II superlattice (T2SL) mid-infrared detectors is designed by exploiting coordinated coupling of the surface plasmon polariton mode and cavity mode in an Au-antenna/detector/highly doped semiconductor ground-plane configuration. By optimizing the doping concentration of the doped semiconductor ground-plane and the size of the antenna, the desired extent of coupling between the modes can be achieved, resulting in enhanced absorption over a broad infrared wavelength band. The absorption in the T2SL active layer in the proposed cavity architecture can be enhanced by nearly 10 times compared with that in the reference structure (without ground-plane and antenna). The cavity architecture is also studied by investigating angular and polarization dependence. This cavity architecture offers potential benefits to type-II superlattice detector performance with minimal growth cost.