Recovery Improvement for Large-Area Tungsten Diselenide Gas Sensors.

Semiconducting two-dimensional transition-metal dichalcogenides are considered promising gas-sensing materials because of their large surface-to-volume ratio, excellent electrical conductivity, and susceptible surfaces. However, enhancement of the recovery performance has not yet been intensively explored. In this study, a large-area uniform WSe2 is synthesized for use in a high-performance semiconductor gas sensor. At room temperature, the WSe2 gas sensor shows a significantly high response (4140%) to NO2 compared to the use of NH3, CO2, and acetone. This paper demonstrates improved recovery of the WSe2 gas sensor's NO2-sensing performance by utilizing external thermal energy. In addition, a novel strategy for improving the recovery of the WSe2 gas sensor is realized by reacting NH3 and adsorbed NO2 on the surface of WSe2: the NO2 molecules are spontaneously desorbed, and the recovery time is dramatically decreased (85 min → 43 s). It is expected that the fast recovery of the WSe2 gas sensor achieved here will be used to develop an environmental monitoring system platform.