Noise analysis of MoTe2-based dual-cavity MOSFET as a pH sensor

Abstract

Abstract Field-effect transistor (FET) pH sensors have been studied for a long time because of their low cost, sound sensitivity, and high operational speed. Recently, transition metal dichalcogenides (TMD) materials such as MoTe2, MoS2, among others, have emerged as promising channel materials for developing energy-efficient electronic devices. TMD-based sensors have shown excellent results because of the high surface area–volume ratio and better bio-specific interaction. This paper proposes and analyzes a MoTe2 channel–based dual-cavity (DC) accumulation metal oxide semiconductor field effect transistor (MOSFET) as a pH sensor. For a comprehensive study, a pH-FET noise model has been considered to investigate the amount of noise associated with the proposed FET under various ionic concentrations and device dimensions. The electrolytic semiconductor has been modeled based on ion dynamics for the simulation study. A site-binding model has been incorporated to capture the surface charge density fluctuations at the interface of electrolyte and gate oxide for different pH values. The effect of gate length scaling on the device performance is studied to comprehend its scalability. With this MoTe2-based DC accumulation MOSFET sensor, a peak threshold sensitivity of 77 mV pH−1 has been achieved. To provide a comparative performance analysis of the proposed work, a benchmarking figure is included and a detailed fabrication methodology is also presented in this paper. All simulations are performed with an experimentally calibrated setup in SILVACO Technology Computer Aided Design (TCAD).