Electromagnetic resonance enhanced photoabsorption in planar metal–oxide–metal tunnel junction detectors

TLDR: In this paper, surface plasmon and guided wave enhanced light absorption in the metal electrodes of planar aluminum-aluminum oxide-silver and aluminum aluminum oxide−aluminum tunnel junctions was investigated.

Abstract: We present calculations of surface plasmon and guided wave enhanced light absorption in the metal electrodes of planar aluminum–aluminum oxide–silver and aluminum–aluminum oxide–aluminum tunnel junctions. We consider excitation, under conditions of attenuated total reflection, of both the ‘‘fast’’ and ‘‘slow’’ surface plasmons of the junction, and of TE and TM guided modes supported by a dielectric film adjoining the junction. We find that >97% absorption may be obtained at resonance in a single electrode of a practical device, the thickness of which is only a fraction of the expected photocarrier mean free path, and show how the angular width of the absorption peak may be varied by changing the adjacent dielectric media. We also show how resonant absorption may be used in a biased planar device for the detection of radiation at normal incidence.