Oxygen-assisted recoverable hydrogen sensor based on sensing gate field effect transistor with ppb-level detection ability

The rise in gas leakage incidents underscores the urgent need for advanced gas-sensing platforms with ultra-low concentration detection capability. Sensing gate field effect transistor (FET) gas sensors, renowned for the gas-induced signal amplification without directly exposing the channel to the ambient environment, play a pivotal role in detecting trace-level hazardous gases with high sensitivity and good stability. In this work, carbon nanotubes are employed as the conducting channel, and yttrium oxide (Y₂O₃) is utilized as the gate dielectric layer. Noble metal Pd is incorporated as a sensing gate for hydrogen (H₂) detection, leveraging its catalytic properties and unique adsorption capability. The fabricated carbon-based FET gas sensor demonstrates a remarkable detection limit of 20 × 10^–9 for H₂ under an air environment, enabling early warning in case of gas leakage. Moreover, the as-prepared sensor exhibited good selectivity, repeatability, and anti-humidity properties. Further experiments elucidate the interaction between H₂ and sensing electrode under an air/nitrogen environment, providing insights into the underlying oxygen-assisted recoverable sensing mechanism. It is our aspiration for this research to establish a robust experimental foundation for achieving high performance and highly integrated fabrication of trace gas sensors.