Static and Dynamic Analyses of Electrostatically Actuated MEMS GO/CMUT Gas Sensor

This paper investigates the static and dynamic behavior of a graphene oxide (GO)-integrated capacitive micromachined ultrasonic transducer (CMUT) for gas sensing applications. A bi-layer lumped-mass analytical model is developed to evaluate the electromechanical response of the hybrid system, considering both GO’s mechanical stiffening effect and its influence on resonance characteristics. Static analysis reveals that the GO layer increases the pull-in voltage from 143 V (bare CMUT) to 147.5 V, enhancing operational stability. Dynamic assessments demonstrate that GO functionalization elevates resonance frequencies due to stiffness-dominated behavior, with a mass sensitivity of 24.19 Hz/pg at 80 V DC. Frequency response analyses under varying DC/AC excitations highlight the system’s linear dynamics, including superharmonic resonances and bifurcation thresholds. The results underscore GO’s role in improving sensitivity, stability, and bandwidth, positioning GO/CMUTs as promising candidates for high-performance gas sensors.