Ultrasensitive gas sensor developed from SnS/TiO2-based memristor for dilute methanol detection at room temperature

Abstract

Metal oxide-based gas sensors are widely studied and applied due to simple operation principle, small size and high stability. However, numerous gas sensors based on metals oxides usually exhibit high optimal operating temperatures and show poor response/recovery performance at room temperature (RT). To overcome the above problems, innovative device forms should be explored. Herein, we developed a memristor-based gas sensor (gasistor) for the detection of dilute methanol vapor at RT, and the resistive layer material was SnS-modified TiO2. Compared with the general film-based gas sensors, the gasistor exhibits unique resistive switching function, and the baseline resistance in the high resistance state is reduced by about 3 × 104 times, demonstrating the construction of gasistor is an effective way to solve the high resistance of metal oxides at RT. Meanwhile, the SnS/TiO2-based gasistor showed a high response of 85.2 for 1 ppm methanol, a fast response/recovery within 1.2 s for rarefied methanol (< 5 ppm), and remarkable selectivity towards methanol at RT. This indicates that the SnS/TiO2-based gasistor is a competitive candidate for methanol detection. Besides, the mechanisms of resistive switching and gas sensing were further discussed. The present work brings new inspiration to the future research of gas sensors.