Probing the Electronic Properties of Monolayer MoS$_2$ via Interaction with Molecular Hydrogen

• Main Authors: Rezende, Natália P, Cadore, Alisson R, Gadelha, Andreij C, Pereira, Cíntia L, Ornelas, Vinicius, Watanabe, Kenji, Taniguchi, Takashi, Ferlauto, André S, Malachias, Ângelo, Campos, Leonardo C, Lacerda, Rodrigo G
• Format: Journal Article
• Language: English
• Published: 04.03.2020
• Subjects: Physics - Applied Physics; Physics - Mesoscale and Nanoscale Physics
• DOI: 10.48550/arxiv.2003.02352

Advanced Electronic Materials, 2019 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 (VS). 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 VS plays an important role in the H$_2$ interaction with the MoS$_2$. These findings provide insights for futures applications in catalytic process between monolayer MoS$_2$ and H$_2$ and also introduce MoS$_2$ FETs as promising H$_2$ sensors.