Plasmon-enhanced high operating temperature infrared photodetectors

Official URL: https://dx.doi.org/10.1117/12.2665259

Plasmonic enhancement has a great potential for performance improvement of high operating temperature (HOT) photodetectors, especially those optimized for long-wavelength infrared (LWIR). Conventional HOT photodetectors exhibit poor quantum efficiency (QE) due to short carrier diffusion lengths of narrow bandgap semiconductors and relatively low absorption coefficients within the LWIR range. Plasmon-driven subwavelength light confinement enables high absorption even in a very thin absorber that provides efficient carrier collection, boosting the detector QE. We propose a photovoltaic detector equipped with a two-dimensional subwavelength hole array (2DSHA) in gold metallization on InAs/InAsSb type-II superlattice (T2SL) heterostructure. Our numerical study utilizing the finite-difference time-domain (FDTD) method predicts five times increased absorption in comparison with a conventional, back-side illuminated device. The simulated behavior of the plasmonic structure was confirmed experimentally by transmittance measurements, which revealed resonant features corresponding to various plasmonic modes.