Scaling Effects on the Plasmonic Enhancement of Butt-Coupled Waveguide Photodetectors

We employed 3D opto-electrical simulations to study the scaling effects of a plasmonic structure on the optical performance of butt-coupled waveguide photodetectors by placing an Ag stripe on top of the intrinsic region. It is found that cutoffs which are limited by carrier drift in the high-field region of the non-plasmonic device improve with longer and wider stripe, while the metal thickness has only little impact. Furthermore, the diffusion and low-field drift limited cut-offs can be eliminated with metal stripes longer than 400 nm.