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Petach TA, Reich KV, Zhang X, Watanabe K, Taniguchi T, Shklovskii BI, Goldhaber-Gordon D. Disorder from the Bulk Ionic Liquid in Electric Double Layer Transistors. ACS Nano 2017; 11:8395-8400. [PMID: 28753312 DOI: 10.1021/acsnano.7b03864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ionic liquid gating has a number of advantages over solid-state gating, especially for flexible or transparent devices and for applications requiring high carrier densities. However, the large number of charged ions near the channel inevitably results in Coulomb scattering, which limits the carrier mobility in otherwise clean systems. We develop a model for this Coulomb scattering. We validate our model experimentally using ionic liquid gating of graphene across varying thicknesses of hexagonal boron nitride, demonstrating that disorder in the bulk ionic liquid often dominates the scattering.
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Affiliation(s)
- Trevor A Petach
- Department of Applied Physics, Stanford University , Palo Alto, California 94305, United States
- Stanford Institute for Materials and Energy Sciences (SIMES), SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Konstantin V Reich
- Fine Theoretical Physics Institute, University of Minnesota , Minneapolis, Minnesota 55455, United States
- Ioffe Institute , St Petersburg, 194021, Russia
| | - Xiao Zhang
- Department of Applied Physics, Stanford University , Palo Alto, California 94305, United States
| | - Kenji Watanabe
- National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Boris I Shklovskii
- Fine Theoretical Physics Institute, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - David Goldhaber-Gordon
- Department of Applied Physics, Stanford University , Palo Alto, California 94305, United States
- Stanford Institute for Materials and Energy Sciences (SIMES), SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
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Petach TA, Mehta A, Marks R, Johnson B, Toney MF, Goldhaber-Gordon D. Voltage-Controlled Interfacial Layering in an Ionic Liquid on SrTiO3. ACS Nano 2016; 10:4565-4569. [PMID: 26959226 DOI: 10.1021/acsnano.6b00645] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
One prominent structural feature of ionic liquids near surfaces is formation of alternating layers of anions and cations. However, how this layering responds to an applied potential is poorly understood. We focus on the structure of 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate (BMPY-FAP) near the surface of a strontium titanate (SrTiO3) electric double-layer transistor. Using X-ray reflectivity, we show that at positive bias the individual layers in the ionic liquid double layer thicken and the layering persists further away from the interface. We model the reflectivity using a modified distorted crystal model with alternating cation and anion layers, which allows us to extract the charge density and the potential near the surface. We find that the charge density is strongly oscillatory with and without applied potential and that with an applied gate bias of 4.5 V the first two layers become significantly more cation rich than at zero bias, accumulating about 2.5 × 10(13) cm(-2) excess charge density.
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Affiliation(s)
- Trevor A Petach
- Department of Physics, Stanford University , Palo Alto, California 94305, United States
| | - Apurva Mehta
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Ronald Marks
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Bart Johnson
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Michael F Toney
- SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
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