Electronic Behavior and Sensing Applications*

In this work, we probe the electronic properties of monolayer MoS₂ via interaction with H₂, aiming for sensing application. The MoS₂ FET exhibit a response to H₂ in a wide range of concentration (0.1-90 %) at relatively low temperatures (300-473 K). These H₂ sensor show desirable properties such absence of catalytic metal dopants (Pt or Pd) and full reversibility. Based in three experiments, we demonstrate that the conductivity of MoS₂ increases as a function of the H₂ concentration due to a reversible charge transferring process. Further, we propose that such process originates from the dissociative H₂ adsorption driven by interaction with sulfur vacancies in the MoS₂ surface (V_S). This proposal is in agreement with related DFT studies about H₂ adsorption on MoS₂. Finally, measurements on partially defect-passivated MoS₂ FETs using atomic layer deposited Al₂O₃ consisting of an experimental indication that the V_S plays an important role in the H₂ interaction with the MoS₂. Our findings provide insights for futures applications in catalytic process between monolayer MoS₂ and H₂.