Field Effect Transistors in Gas Sensing

Field effect transistor (FET) gas sensors have experienced significant advancements in recent years, particularly in semiconductor-based platforms for gas detection applications. The special qualities of materials including silicon nanowires, carbon nanotubes, and 2D nanomaterials have been used to investigate a variety of sensor architectures. These structures have been carefully designed to enhance sensitivity and selectivity, enabling the detection of a wide range of gases with high precision. Optimization strategies have been implemented to improve sensor performance, including monitoring response parameters and developing dual-mode and logic circuit sensors. Dual-mode sensors, such as those combining p-type silicon nanoribbon FETs with film bulk acoustic resonators, have shown promise in detecting specific gases like chlorofluorocarbons and halogenated hydrochlorofluorocarbons. Semiconductor nanomaterials, including transition metal dichalcogenides (TMDC), have become more attractive platforms for gas sensing, ability to detect gases with great sensitivity, such as NH 3 and NO 2 . Functionalization of nanomaterials, such as MoS 2 with nanoparticles like Pd, has further improved gas-sensing behaviors, especially in detecting gases like H 2 with enhanced response rates. The future of FET gas sensors involves addressing challenges like improving subthreshold swing and reliability, as well as exploring novel heterostructures to enhance performance and expand the range of detectable gases. This chapter provides a comprehensive overview of FET gas sensor device structures, gas-sensing nanomaterials and mechanisms, performance improvement strategies, challenges, and applications. Furthermore, it discusses the existing challenges in FET gas sensors and offers potential solutions to enhance their performance for various applications. Given the current advancements and potential future improvements, this chapter highlights the potential of FET gas sensors in diverse applications, from health and environmental monitoring to industrial safety, paving the way for future innovations in gas-sensing technology.