Carbon-based field-effect transistor gas sensor modulated by gate electric field for trace-level hydrogen sulfide detection.

Inspired by the signal amplification property of the field-effect transistor (FET) enabled by electric field modulation across the conducting channel, a carbon-based FET hydrogen sulfide (H2S) sensor with ionogel sensing material was fabricated, providing trace-level detection without the need of thermal or optical fields. Under an applied back-gate voltage, the working state of the FET sensor could be regulated to the linear region, significantly boosting the sensor’s sensitivity toward low-concentration analytes. The proposed sensor exhibited a room-temperature detection ability toward 0.1-1 ppm of H2S. Leveraging the hydrophobic nature of the ionogel, the sensor showed a slight response variation (6.8%) toward 1 ppm of H2S in the range 10–90% relative humidity (RH). This work provides an electric field modulation strategy for trace-level gas detection, offering a feasible solution for the chip-integrated development of gas sensors.