Ion Migration Studies in Exfoliated 2D Molybdenum Oxide via Ionic Liquid Gating for Neuromorphic Device Applications

Cheng Zhang, Pushpa R. Pudasaini, Akinola D. Oyedele, Anton V. Ievlev, Liubin Xu, Amanda V. Haglund, Joo Hyon Noh, Anthony T. Wong, Kai Xiao, Thomas Z. Ward, David G. Mandrus, Haixuan Xu, Olga S. Ovchinnikova, Philip D. Rack

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The formation of an electric double layer in ionic liquid (IL) can electrostatically induce charge carriers and/or intercalate ions in and out of the lattice which can trigger a large change of the electronic, optical, and magnetic properties of materials and even modify the crystal structure. We present a systematic study of ionic liquid gating of exfoliated 2D molybdenum trioxide (MoO3) devices and correlate the resultant electrical properties to the electrochemical doping via ion migration during the IL biasing process. A nearly 9 orders of magnitude modulation of the MoO3 conductivity is obtained for the two types of ionic liquids that are investigated. In addition, notably rapid on/off switching was realized through a lithium-containing ionic liquid whereas much slower modulation was induced via oxygen extraction/intercalation. Time of flight-secondary ion mass spectrometry confirms the Li intercalation. Density functional theory (DFT) calculations have been carried out to examine the underlying metallization mechanism. Results of short-pulse tests show the potential of these MoO3 devices as neuromorphic computing elements due to their synaptic plasticity.

Original languageEnglish
Pages (from-to)22623-22631
Number of pages9
JournalACS Applied Materials and Interfaces
Volume10
Issue number26
DOIs
StatePublished - Jul 5 2018

Funding

P.D.R., C.Z., P.R.P., and M.G.S acknowledge support by U.S. Department of Energy (DOE) under Grant DE-SC0002136. D.G.M. and A.V.H. acknowledge funding by the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant GBMF4416. T.Z.W. acknowledges support by U.S. DOE, Office of Basic Energy Sciences (BES), Materials Sciences and Engineering Division. A.T.W. acknowledges support by Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy. A portion of this research was conducted by A.V.L. and O.S.O. at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility, and using instrumentation within ORNL’s Materials Characterization Core provided by UT-Battelle, LLC under Contract DE-AC05-00OR22725 with the U.S. DOE. H.X. and L.X. acknowledge the support of Organized Research Unit Program (ORU-IMHM-18) at the University of Tennessee.

Keywords

  • 2D materials
  • ion migration
  • ionic liquid
  • neuromorphic device
  • transition metal oxides

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