Fabrication and characterization of humidity sensors based on CVD grown MoS2 thin film

Recent advances in two-dimensional (2D) transition metal dichalcogenides have demonstrated their potential application in chemical sensors. However, the chemical vapor deposition (CVD) grown molybdenum disulfide (MoS2) humidity sensors are still largely unexplored. In this work, MoS2 thin films were grown on 1 cm2 sapphire substrates through sulfurization of e-beam deposited Mo layers. The MoS2 film morphology, thickness, and crystallinity were characterized by AFM and Raman spectroscopy. The two-terminal devices were fabricated with e-beam evaporated interdigitated electrodes (IDEs) on top of the MoS2 surface. The water vapor sensing was tested at various humidity levels with the observed increase in the device resistance response to humidity due to the charge transfer mechanism. We found the devices to be reproducible and with excellent dynamic hysteresis. The sensitivity, fast response and recovery proved that CVD growth MoS2 thin film could be scaled up for humidity and gas sensing applications.