Probing the Electronic Properties of Monolayer MoS2 Via Interaction with Molecular Hydrogen

This work presents a detailed experimental investigation of the interaction between molecular hydrogen (H 2 ) and monolayer MoS 2 field effect transistors (MoS 2 FET), aiming for sensing application. The MoS 2 FET exhibits a response to H 2 that covers a broad range of concentration (0.1–90%) at a relatively low operating temperature range (300–473 K). Most important, H 2 sensors based on MoS 2 FETs show desirable properties such as full reversibility and absence of catalytic metal dopants (Pt or Pd). The experimental results indicate that the conductivity of MoS 2 monotonically increases as a function of the H 2 concentration due to a reversible charge transferring process. It is proposed that such process involves dissociative H 2 adsorption driven by interaction with sulfur vacancies in the MoS 2 surface ( V S ). This description is in agreement with related density functional theory studies about H 2 adsorption on MoS 2 . Finally, measurements on partially defect‐passivated MoS 2 FETs using atomic layer deposited aluminum oxide consist of an experimental indication that the V S plays an important role in the H 2 interaction with the MoS 2 . These findings provide insights for future applications in catalytic process between monolayer MoS 2 and H 2 and also introduce MoS 2 FETs as promising H 2 sensors.