Plasmonic Nanoslit Array Enhanced Metal-Semiconductor-Metal Optical Detectors

TL;DR

This paper demonstrates that metallic nanoslit arrays can significantly enhance the absorption in germanium-based M-S-M photodetectors through surface plasmon resonances, improving their efficiency in the telecommunication C-band.

Contribution

It reveals that horizontal surface plasmon modes, previously thought to inhibit performance, actually enhance device efficiency despite reducing far-field transmission.

Findings

Absorption in photodetectors is increased by nanoslit arrays.

Horizontal surface plasmon modes can improve device efficiency.

Resonant interference enhances surface device performance.

Abstract

Metallic nanoslit arrays integrated on germanium metal-semiconductor-metal photodetectors show many folds of absorption enhancement for transverse-magnetic polarization in the telecommunication C-band. Such high enhancement is attributed to resonant interference of surface plasmon modes at the metal-semiconductor interface. Horizontal surface plasmon modes were reported earlier to inhibit photodetector performance. We computationally show, however, that horizontal modes enhance the efficiency of surface devices despite reducing transmitted light in the far field.