Optoelectronic control of surface plasmon polaritons at metal-doped semiconductor interfaces

Abstract We present a metal–semiconductor (M–S) based electro-optic modulator designed for functional plasmonic circuits, utilizing the active control of surface plasmon polaritons (SPPs) at M–S junction interfaces. Through self-consistent multiphysics simulations, including electromagnetic, thermal, and current–voltage ( IV ) characteristics, we estimate bias- and doping concentration-dependent SPP modulation and switching times. This study focuses on germanium-based Schottky contacts and can be extended to other semiconducting materials. We performed parametric analysis using the developed thermo-electro-optic model to identify device parameters and dimensions for enhanced optical confinement and faster operation. The studied device exhibits signal modulation exceeding −28 dB, responsivity greater than −1800 dB V −1 , and switching rates of 8 GHz, suggesting potential data rates above 16 Gbit s −1 . Additionally, frequency response analysis using the numerical model confirms the device’s electrical tunability and predicts a 3 dB bandwidth of up to 4 GHz. These findings highlight the significant potential of Schottky junctions as active components in the development of plasmonic-based integrated circuits.