Plasmonic enhancement of light trapping in photodetectors

Abstract

We consider the possibility to use plasmonics to enhance light trapping in such semiconductor detectors as solar cells and infrared detectors for night vision. Plasmonic structures can transform propagating electromagnetic waves into evanescent waves with the local density of states vastly increased within subwavelength volumes compared to the free space, thus surpassing the conventional methods for photon management. We show how one may utilize plasmonic nanoparticles both to squeeze the optical field into the active region and to increase the optical path by Mie scattering, apply ordered plasmonic nanocomposites (subwavelength plasmonic crystals or plasmonic metamaterials), or design nanoantennas to maximize absorption within the detector. We show that many approaches used for solar cells can be also utilized in infrared range if different redshifting strategies are applied.