Investigation of humidity sensing properties based on graphene oxide/molybdenum disulfide composite

Two-dimensional nanomaterials have special capabilities in gas sensors due to features such as high surface-to-volume ratio and multiple active sites. In this research, molybdenum disulfide nanosheets, graphene oxide and their composites were prepared by liquid exfoliation, Hammers, and sonochemical methods, respectively. Physical properties of the prepared nanomaterials were evaluated using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Then the humidity sensors were prepared based on these materials on Si/SiO2 substrates and using copper electrodes. Due to the different types of carriers in graphene oxide and molybdenum disulfide (p-type and n-type, respectively), the current changes in different moisture percentages were obtained differently for these two sensors, and the behavior of the sensor based on the composite of these two materials was more similar to the behavior of graphene. The recovery time and response time of all three sensors were measured within 20 seconds. The results showed that the composite of graphene oxide and molybdenum disulfide, has a better humidity sensor behaviour rather than molybdenum disulfide nanosheets.