Electrical modulation of degenerate semiconductor plasmonic interfaces

Abstract

We demonstrate electrical modulation of plasmonic interfaces in semiconductor p-n++ junctions fabricated from both III–V and Si materials. Junction diodes are grown/fabricated, consisting of degenerately doped n-type material and heavily doped p-type material, where the n++ semiconductor acts as a plasmonic material capable of supporting infrared propagating surface plasmon polaritons. Devices were characterized electrically and optically, and we achieved tuning of the reflectivity under applied bias with amplitude reaching 1.5% in mid-IR wavelengths. We developed a model of electrical carrier injection at the degenerately doped interface, which we used to model the bias-dependent optical properties of the system. A strong agreement between our model and experimental results is demonstrated. The presented devices offer the opportunity for electrical modulation of propagating plasmonic modes in an all-semiconductor system.