Light-Assisted and Gate-Tunable Oxygen Gas Sensor based on Rhenium Disulfide (ReS2) Field-Effect Transistors

Gas sensors based on transition metal dichalcogenides (TMDCs) have attracted much attention from a new perspective involving light-assisted or gate-voltage operation. However, their combined roles as regards the gas sensing performance and mechanism are not yet understood due to the lack of controlled studies. This study systematically investigates the oxygen sensor performance and mechanism of few-layer-thick rhenium disulfide (ReS2) field-effect transistors (FETs) under light illumination and gate biasing. As a result, a combination of light illumination and positive gate voltage enhances the device response over 100% at a 1% oxygen concentration; that is, the approach achieves a practical sensitivity of 0.01% ppm(-1), which outperforms most of the reports available in the literature. Furthermore, the fabricated devices exhibit long-term stability and stable operation even under humid conditions, indicating the ability of the sensor device to operate in a real-time application. These results contribute to the development of versatile tunable oxygen sensors based on TMDC FETs.