Electron Mobility Sensor Scheme-Based on a Mach–Zehnder Interferometer Approach

Abstract

This letter presents the use of a plasmonic sensing transducer on an embedded Mach–Zehnder interferometer (MZI) arm, allowing the sensing transducer to be formed through the stacked layers of the silicon–graphene–gold materials and embedded on an MZI arm with a gripping force to allow it to be used in sensing applications. The transduction process introduces an energy conversion between the input light and the excited electron mobility within the silicon and graphene layers. That way the electron drift velocity within the gold layer can drive the plasmonic wave group velocity induced through the interaction with the graphene layers, and consequently, the electron mobility in the gold layer increases. The driven electron mobility in the gold layer, caused by the plasmonic waves from graphene in the embedded sensing layers, will affect the electron output mobility, where the relative change in the phase of the light in the silicon can be seen at the output port of the MZI. To optimize the key parameters of such a system (especially input optical power and dimensions of the gold layer), simulations are performed at various input optical powers and the results are graphically represented. A maximum sensitivity of ~ $2\times {10}^{-14}$ mV−1s−1 in electron mobility sensing is obtained through these simulations, designed to optimize the performance characteristics of the proposed sensor.