Insight into mechanism of temperature-dependent limit of NO2 detection using monolayer MoS2

초록

Recently, many literatures report on the excellent performance of MoS2-based NO2 sensing, however, lacking the study on its thermal stability. Here, the insight mechanism in NO2 sensor reactivity of monolayer MoS2 at different temperatures from 25 to 200 degrees C was investigated. The relative effect of the morphological properties of the sensor and gas sensor reactivity at different temperatures was observed using in situ Raman mapping, optical microscope, and scanning electron microscope to demonstrate the mechanism of temperature-dependent limit of NO2 detection in ppb. By increasing the temperature from 25 to 100 degrees C, the response of the sensor significantly improves (4.8 % vs. 54.4 %) at 200 ppb, and its limit of NO2 detection strongly decreases (48.0 vs. 6.9 ppb). Interestingly, the sensor performance from 100 to 150 degrees C is likely equivalent to a limit of detection (LoD) that varies from 8.1 to 6.9 ppb, and the LoD slightly increases to 15.0 ppb at 200 degrees C. The line damages were found in monolayer MoS2 basal plane by heating the sample up to 200 degrees C, that affect to the recovery of the NO2 sensor. This study reveals an effective approach that may be useful in developing a gas sensor with a high response and limit of NO2 detection in the ppb scale.

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