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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. 

We present a transient response study of a semiconductor based plasmonic switch. The proposed device operates through active control and modulation of localized electron density waves, i.e., surface plasmon polaritons (SPPs) at degenerately doped In_0.53Ga_0.47As based PN⁺⁺junctions. A set of devices is designed and fabricated, and its optical and electronic behaviors are studied both experimentally and theoretically. Optical characterization shows far-field reflectivity modulation, a result of electrical tuning of the SPPs at the PN⁺⁺junctions for mid-IR wavelengths, with significant 3 dB bandwidths. Numerical studies using a self-consistent electro-optic multi-physics model are performed to uncover the temporal response of the devices’ electromagnetic and kinetic mechanisms facilitating the SPP switching at the PN⁺⁺junctions. Numerical simulations show strong synergy with the experimental results, validating the claim of potential optoelectronic switching with a 3 dB bandwidth as high as 2 GHz. Thus, this study confirms that the presented SPP diode architecture can be implemented for high-speed control of SPPs through electrical means, providing a pathway toward fast all-semiconductor plasmonic devices.