A novel room temperature SO2 gas sensor based on TiO2/rGO buried-gate FET

Gas sensors are able to detect the type and concentration of flammable, explosive, toxic gases (e.g. NO2, SO2, NH3), showing wide applications in petroleum, chemical, medical, transportation and safety protections in the domestic and industrial environment. Currently, the SO2 gas sensors are mainly based on metal oxide semiconductors. However, its operating temperature is generally much higher than room temperature, and the operation at higher temperature often requires complex circuits and high power consumption. A novel room temperature (RT) SO2 gas sensor based on buried-gate field effect transistor (FET) and interdigitated electrode structure with titanium dioxide (TiO2) nanoparticles and reduced graphene oxide (rGO) composite materials as gas-sensitive layer, has been fabricated and demonstrated in this paper. The TiO2/rGO FET sensor shows a relative high responsivity (3.46%) to 20 part per million (ppm) SO2 gas, under a source-drain voltage of 2 V and a zero gate voltage. Experimental results have shown that the responsivity and response-recovery time of the sensor could be controlled by the source-drain voltage. This paper demonstrates the feasibility of TiO2/rGO nanocomposite as a gas-sensing material for high-performance SO2 gas sensors. In addition, this approach would provide a feasible way for the realization of miniaturized, integrated and high-performance SO2 gas sensors.