Edge enriched MoS2 micro flowered structure for high performance NO2 sensor

In this work, we showed that the chemisorption of nitrogen oxide (NO2) gas molecule is significantly enhanced in the case of a vertically oriented (VO) MoS2-based device, at low operating temperature. We fabricated a VO-MoS2-micro flower layer using the hydrothermal process followed by the sonication technique. To determine the surface morphology and crystallinity of the MoS2 nanosheets, we have done microscopy and spectroscopy analysis, while to confirm the vertical orientation of MoS2 we performed Raman spectroscopy. We observed that the MoS2 orientation has a significant impact on the gas sensing performance. The presence of unsaturated and dangling bonds on the sensing surface encourages the strong chemisorption process of analyte gas molecules. We have examined the gas sensing performance for the fabricated device at different concentration levels of NO2 gas molecules. Moreover, we also evaluated the stability, response, and recovery time of the device toward 50 ppm of NO2 gas molecule. The fabricated device exhibited a response and recovery time of-13 and-110 s, respectively, upon exposure to 50 ppm of NO2. Further, the proposed device was exposed to various other gas molecules to examine the selectivity and it shows excellent sensing response towards NO2 gas molecules.