1
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Park DS, Rata AD, Dahm RT, Chu K, Gan Y, Maznichenko I, Ostanin S, Trier F, Baik H, Choi WS, Choi CJ, Kim YH, Rees GJ, Gíslason HP, Buczek PA, Mertig I, Ionescu MA, Ernst A, Dörr K, Muralt P, Pryds N. Controlled Electronic and Magnetic Landscape in Self-Assembled Complex Oxide Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300200. [PMID: 37154173 DOI: 10.1002/adma.202300200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 05/01/2023] [Indexed: 05/10/2023]
Abstract
Complex oxide heterointerfaces contain a rich playground of novel physical properties and functionalities, which give rise to emerging technologies. Among designing and controlling the functional properties of complex oxide film heterostructures, vertically aligned nanostructure (VAN) films using a self-assembling bottom-up deposition method presents great promise in terms of structural flexibility and property tunability. Here, the bottom-up self-assembly is extended to a new approach using a mixture containing a 2Dlayer-by-layer film growth, followed by a 3D VAN film growth. In this work, the two-phase nanocomposite thin films are based on LaAlO3 :LaBO3 , grown on a lattice-mismatched SrTiO3001 (001) single crystal. The 2D-to-3D transient structural assembly is primarily controlled by the composition ratio, leading to the coexistence of multiple interfacial properties, 2D electron gas, and magnetic anisotropy. This approach provides multidimensional film heterostructures which enrich the emergent phenomena for multifunctional applications.
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Affiliation(s)
- Dae-Sung Park
- Institute of Materials, Swiss Federal Institute of Technology-EPFL, Lausanne, 1015, Switzerland
- Department of Energy Conversion and Storage, Technical University of Denmark, Kgs Lyngby, DK-2800, Denmark
- Institute of Electrical and Micro Engineering, Swiss Federal Institute of Technology-EPFL, Lausanne, 1015, Switzerland
| | - Aurora Diana Rata
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle, Germany
| | - Rasmus Tindal Dahm
- Department of Energy Conversion and Storage, Technical University of Denmark, Kgs Lyngby, DK-2800, Denmark
| | - Kanghyun Chu
- Institute of Materials, Swiss Federal Institute of Technology-EPFL, Lausanne, 1015, Switzerland
| | - Yulin Gan
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Igor Maznichenko
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle, Germany
| | - Sergey Ostanin
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle, Germany
| | - Felix Trier
- Department of Energy Conversion and Storage, Technical University of Denmark, Kgs Lyngby, DK-2800, Denmark
| | - Hionsuck Baik
- Korea Basic Science Institute, Seoul, 02841, Republic of Korea
| | - Woo Seok Choi
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Chel-Jong Choi
- School of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju, 54596, Republic of Korea
| | - Young Heon Kim
- Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Gregory Jon Rees
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
| | | | - Paweł Adam Buczek
- Department of Engineering and Computer Sciences, Hamburg University of Applied Sciences, 20099, Hamburg, Germany
| | - Ingrid Mertig
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle, Germany
| | - Mihai Adrian Ionescu
- Institute of Electrical and Micro Engineering, Swiss Federal Institute of Technology-EPFL, Lausanne, 1015, Switzerland
| | - Arthur Ernst
- Max-Planck-Institut für Mikrostrukturphysik, 06120, Halle, Germany
- Institute of Theoretical Physics, Johannes Kepler University, Linz, 4040, Austria
| | - Kathrin Dörr
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle, Germany
| | - Paul Muralt
- Institute of Materials, Swiss Federal Institute of Technology-EPFL, Lausanne, 1015, Switzerland
| | - Nini Pryds
- Department of Energy Conversion and Storage, Technical University of Denmark, Kgs Lyngby, DK-2800, Denmark
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2
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Yang R, Gao Y, Wang S, Jin K. High-Mobility Magnetic Two-Dimensional Electron Gas in Engineered Oxide Interfaces. ACS APPLIED MATERIALS & INTERFACES 2023; 15:2376-2383. [PMID: 36577504 DOI: 10.1021/acsami.2c17638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The engineered interfaces of complex oxides have abundant physical properties and provide a powerful platform for the exploration of fundamental physics and emergent phenomena. In particular, research on the two-dimensional magnetic systems with high mobility remains a long-standing challenge for the discovery of quantum phase and spintronic applications. Here, we introduce a few atomic layers of the delta doping layer at LaAlO3/SrTiO3 interfaces through elaborately controllable epitaxial growth of SrRuO3. After inserting a SrRuO3 buffer layer, the interfaces exhibit a well-defined anomalous Hall effect up to 100 K and their mobility is enhanced by 3 orders of magnitude at low temperatures. More intriguingly, a large unsaturated positive magnetoresistance is created at interfaces. Combining with the density functional theory calculation, we attribute our findings to the electron transfer at interfaces and the magnetic moment of Ru4+ 4d bands. The results pave a way for further research of two-dimensional ferromagnetism and quantum transport in all-oxide systems.
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Affiliation(s)
- Ruishu Yang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry Under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an710072, China
| | - Yuqiang Gao
- Department of Physics, School of Physics and Electronic Information, Anhui Normal University, Wuhu241000, China
| | - Shuanhu Wang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry Under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an710072, China
| | - Kexin Jin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry Under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an710072, China
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3
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Lei B, Ma D, Liu S, Sun Z, Shi M, Zhuo W, Yu F, Gu G, Wang Z, Chen X. Manipulating high-temperature superconductivity by oxygen doping in Bi 2Sr 2CaCu 2O 8+δ thin flakes. Natl Sci Rev 2022; 9:nwac089. [PMID: 36415315 PMCID: PMC9671661 DOI: 10.1093/nsr/nwac089] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 01/17/2022] [Accepted: 02/15/2022] [Indexed: 09/08/2024] Open
Abstract
Harnessing the fascinating properties of correlated oxides requires precise control of their carrier density. Compared to other methods, oxygen doping provides an effective and more direct way to tune the electronic properties of correlated oxides. Although several approaches, such as thermal annealing and oxygen migration, have been introduced to change the oxygen content, a continuous and reversible solution that can be integrated with modern electronic technology is much in demand. Here, we report a novel ionic field-effect transistor using solid Gd-doped CeO2 as the gate dielectric, which shows a remarkable carrier-density-tuning ability via electric-field-controlled oxygen concentration at room temperature. In Bi2Sr2CaCu2O8+δ (Bi-2212) thin flakes, we achieve a reversible superconductor-insulator transition by driving oxygen ions in and out of the samples with electric fields, and map out the phase diagram all the way from the insulating regime to the over-doped superconducting regime by continuously changing the oxygen doping level. Scaling analysis indicates that the reversible superconductor-insulator transition for the Bi-2212 thin flakes follows the theoretical description of a two-dimensional quantum phase transition. Our work provides a route for realizing electric-field control of phase transition in correlated oxides. Moreover, the configuration of this type of transistor makes heterostructure/interface engineering possible, thus having the potential to serve as the next-generation all-solid-state field-effect transistor.
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Affiliation(s)
- Bin Lei
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
- CASCenter for Excellence in Quantum Information and Quantum Physics, Hefei 230026, China
| | - Donghui Ma
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Shihao Liu
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zeliang Sun
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Mengzhu Shi
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Weizhuang Zhuo
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Fanghang Yu
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Genda Gu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973-5000, USA
| | - Zhenyu Wang
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
- CASCenter for Excellence in Quantum Information and Quantum Physics, Hefei 230026, China
| | - Xianhui Chen
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, China
- CASCenter for Excellence in Quantum Information and Quantum Physics, Hefei 230026, China
- CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai 200050, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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Li M, Zhou Y, Chen Y, Yang R, Wei X, Wang S, Jin K. Effect of Rare Earth Elements at Amorphous ReAlO 3/SrTiO 3 (Re = La, Pr, Nd, Sm, Gd, and Tm) Heterointerfaces. J Phys Chem Lett 2021; 12:1657-1663. [PMID: 33555878 DOI: 10.1021/acs.jpclett.0c03685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Although the amorphous two-dimensional electron gas (a-2DEG) of oxides provides new opportunities to explore nanoelectronic as well as quantum devices, the intrinsic effect of rare earth (Re = La, Pr, Nd, Sm, Gd, and Tm) elements at ReAlO3/SrTiO3 heterointerfaces is still largely unknown and needs to be addressed systematically. Herein, we first propose that the ionization potential of Re elements is a critical factor for the 2DEG fabricated by chemical spin coating. Furthermore, the photoresponsive properties of heterointerfaces are investigated comprehensively with the ionization potential ranging from 35.79 to 41.69 eV. The results show that the sheet resistances significantly increase with increasing the ionization potential, and a resistance upturn phenomenon is observed at TmAlO3/SrTiO3 heterointerfaces, which can be attributed to the weak localization effect theoretically. The most important observation is the dramatic transition from negative (-178.3%, Re = La) to positive (+89.9%, Re = Gd) photoresponse at ReAlO3/SrTiO3 heterointerfaces under the irradiation of 405 nm light at 50 K. More remarkably, a unique recovery behavior of transient-persistent photoconductivity coexistence at low temperatures is discovered at the TmAlO3/SrTiO3 heterointerface. This work reveals an effective approach to tune the transport and photoresponsive properties by changing Re elements and paves the way for the application of all-oxide devices.
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Affiliation(s)
- Ming Li
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - You Zhou
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yunhai Chen
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Ruishu Yang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Xiangyang Wei
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Shuanhu Wang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Kexin Jin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
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5
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Song D, Xue D, Zeng S, Li C, Venkatesan T, Ariando A, Pennycook SJ. Atomic Origin of Interface-Dependent Oxygen Migration by Electrochemical Gating at the LaAlO 3-SrTiO 3 Heterointerface. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000729. [PMID: 32775157 PMCID: PMC7404156 DOI: 10.1002/advs.202000729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/30/2020] [Indexed: 06/11/2023]
Abstract
Electrical control of material properties based on ionic liquids (IL) has seen great development and emerging applications in the field of functional oxides, mainly understood by the electrostatic and electrochemical gating mechanisms. Compared to the fast, flexible, and reproducible electrostatic gating, electrochemical gating is less controllable owing to the complex behaviors of ion migration. Here, the interface-dependent oxygen migration by electrochemical gating is resolved at the atomic scale in the LaAlO3-SrTiO3 system through ex situ IL gating experiments and on-site atomic-resolution characterization. The difference between interface structures leads to the controllable electrochemical oxygen migration by filling oxygen vacancies. The findings not only provide an atomic-scale insight into the origin of interface-dependent electrochemical gating but also demonstrate an effective way of engineering interface structure to control the electrochemical gating.
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Affiliation(s)
- Dongsheng Song
- Department of Materials Science and EngineeringNational University of SingaporeSingapore117575Singapore
- NUSNNI‐NanocoreNational University of SingaporeSingapore117411Singapore
| | - Deqing Xue
- Department of Materials Science and EngineeringNational University of SingaporeSingapore117575Singapore
| | - Shengwei Zeng
- NUSNNI‐NanocoreNational University of SingaporeSingapore117411Singapore
- Department of PhysicsNational University of SingaporeSingapore117542Singapore
| | - Changjian Li
- Department of Materials Science and EngineeringNational University of SingaporeSingapore117575Singapore
- NUSNNI‐NanocoreNational University of SingaporeSingapore117411Singapore
| | - Thirumalai Venkatesan
- Department of Materials Science and EngineeringNational University of SingaporeSingapore117575Singapore
- NUSNNI‐NanocoreNational University of SingaporeSingapore117411Singapore
- Department of PhysicsNational University of SingaporeSingapore117542Singapore
| | - Ariando Ariando
- NUSNNI‐NanocoreNational University of SingaporeSingapore117411Singapore
- Department of PhysicsNational University of SingaporeSingapore117542Singapore
| | - Stephen J. Pennycook
- Department of Materials Science and EngineeringNational University of SingaporeSingapore117575Singapore
- NUSNNI‐NanocoreNational University of SingaporeSingapore117411Singapore
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6
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Zhuang Y, Cui B, Yang H, Gao F, Parkin SSP. Ionic Liquid Gate-Induced Modifications of Step Edges at SrCoO 2.5 Surfaces. ACS NANO 2020; 14:8562-8569. [PMID: 32609490 PMCID: PMC7467809 DOI: 10.1021/acsnano.0c02880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
Intense electric fields developed during gating at the interface between an ionic liquid and an oxide layer have been shown to lead to significant structural and electronic phase transitions in the entire oxide layer. An archetypical example is the reversible transformation between the brownmillerite SrCoO2.5 and the perovskite SrCoO3 engendered by ionic liquid gating. Here we show using in situ atomic force microscopy studies with photothermal excitation detection, that allows for high quality measurements in the viscous environment of the ionic liquid that the edges of atomically smooth terraces at the surface of SrCoO2.5 films are significantly modified by ionic liquid gating but that the terraces themselves remain smooth. The edges develop ridges that we show, using complementary X-ray photoemission spectroscopy studies, result from the adsorption of hydroxyl groups. Our findings exhibit a way of electrically controlled surface modifications in emergent ionitronic applications.
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Affiliation(s)
| | | | - Hao Yang
- Max Planck Institute for Microstructure
Physics, Halle (Saale) 06120, Germany
| | - Fang Gao
- Max Planck Institute for Microstructure
Physics, Halle (Saale) 06120, Germany
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7
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Zeng SW, Yin XM, Herng TS, Han K, Huang Z, Zhang LC, Li CJ, Zhou WX, Wan DY, Yang P, Ding J, Wee ATS, Coey JMD, Venkatesan T, Rusydi A, Ariando A. Oxygen Electromigration and Energy Band Reconstruction Induced by Electrolyte Field Effect at Oxide Interfaces. PHYSICAL REVIEW LETTERS 2018; 121:146802. [PMID: 30339445 DOI: 10.1103/physrevlett.121.146802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Indexed: 06/08/2023]
Abstract
Electrolyte gating is a powerful means for tuning the carrier density and exploring the resultant modulation of novel properties on solid surfaces. However, the mechanism, especially its effect on the oxygen migration and electrostatic charging at the oxide heterostructures, is still unclear. Here we explore the electrolyte gating on oxygen-deficient interfaces between SrTiO_{3} (STO) crystals and LaAlO_{3} (LAO) overlayer through the measurements of electrical transport, x-ray absorption spectroscopy, and photoluminescence spectra. We found that oxygen vacancies (O_{vac}) were filled selectively and irreversibly after gating due to oxygen electromigration at the amorphous LAO/STO interface, resulting in a reconstruction of its interfacial band structure. Because of the filling of O_{vac}, the amorphous interface also showed an enhanced electron mobility and quantum oscillation of the conductance. Further, the filling effect could be controlled by the degree of the crystallinity of the LAO overlayer by varying the growth temperatures. Our results reveal the different effects induced by electrolyte gating, providing further clues to understand the mechanism of electrolyte gating on buried interfaces and also opening a new avenue for constructing high-mobility oxide interfaces.
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Affiliation(s)
- S W Zeng
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - X M Yin
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603, Singapore
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - T S Herng
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117576, Singapore
| | - K Han
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Z Huang
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - L C Zhang
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - C J Li
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117576, Singapore
| | - W X Zhou
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - D Y Wan
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - P Yang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - J Ding
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117576, Singapore
| | - A T S Wee
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
- Centre for Advanced 2D Materials and Graphene Research, National University of Singapore, Singapore 117546, Singapore
| | - J M D Coey
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- School of Physics and CRANN, Trinity College, Dublin 2, Ireland
| | - T Venkatesan
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117576, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore
- National University of Singapore Graduate School for Integrative Sciences and Engineering (NGS), 28 Medical Drive, Singapore 117456, Singapore
| | - A Rusydi
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - A Ariando
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
- National University of Singapore Graduate School for Integrative Sciences and Engineering (NGS), 28 Medical Drive, Singapore 117456, Singapore
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8
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Chen L, Li J, Tang Y, Pai YY, Chen Y, Pryds N, Irvin P, Levy J. Extreme Reconfigurable Nanoelectronics at the CaZrO 3 /SrTiO 3 Interface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1801794. [PMID: 29962024 DOI: 10.1002/adma.201801794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/10/2018] [Indexed: 06/08/2023]
Abstract
Complex oxide heterostructures have fascinating emergent properties that originate from the properties of the bulk constituents as well as from dimensional confinement. The conductive behavior of the polar/nonpolar LaAlO3 /SrTiO3 interface can be reversibly switched using conductive atomic force microscopy (c-AFM) lithography, enabling a wide range of devices and physics to be explored. Here, extreme nanoscale control over the CaZrO3 /SrTiO3 (CZO/STO) interface, which is formed from two materials that are both nonpolar, is reported. Nanowires with measured widths as narrow as 1.2 nm are realized at the CZO/STO interface at room temperature by c-AFM lithography. These ultrathin nanostructures have spatial dimensions at room temperature that are comparable to single-walled carbon nanotubes, and hold great promise for alternative oxide-based nanoelectronics, as well as offer new opportunities to investigate the electronic structure of the complex oxide interfaces. The cryogenic properties of devices constructed from quasi-1D channels, tunnel barriers, and planar gates exhibit gate-tunable superconductivity, quantum oscillations, electron pairing outside of the superconducting regime, and quasi-ballistic transport. This newly demonstrated ability to control the metal-insulator transition at nonpolar oxide interface greatly expands the class of materials whose behavior can be patterned and reconfigured at extreme nanoscale dimensions.
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Affiliation(s)
- Lu Chen
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, PA, 15260, USA
| | - Jianan Li
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, PA, 15260, USA
| | - Yuhe Tang
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, PA, 15260, USA
| | - Yun-Yi Pai
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, PA, 15260, USA
| | - Yunzhong Chen
- Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, Roskilde, 4000, Denmark
| | - Nini Pryds
- Department of Energy Conversion and Storage, Technical University of Denmark, Risø Campus, Roskilde, 4000, Denmark
| | - Patrick Irvin
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, PA, 15260, USA
| | - Jeremy Levy
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Pittsburgh Quantum Institute, Pittsburgh, PA, 15260, USA
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9
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Jnawali G, Lee H, Lee JW, Huang M, Hsu JF, Bi F, Zhou R, Cheng G, D'Urso B, Irvin P, Eom CB, Levy J. Graphene-Complex-Oxide Nanoscale Device Concepts. ACS NANO 2018; 12:6128-6136. [PMID: 29750506 DOI: 10.1021/acsnano.8b02457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The integration of graphene with complex-oxide heterostructures such as LaAlO3/SrTiO3 offers the opportunity to combine the multifunctional properties of an oxide interface with the exceptional electronic properties of graphene. The ability to control interface conduction through graphene and understanding how it affects the intrinsic properties of an oxide interface are critical to the technological development of multifunctional devices. Here we demonstrate several device archetypes in which electron transport at an oxide interface is modulated using a patterned graphene top-gate. Nanoscale devices are fabricated at the oxide interface by conductive atomic force microscope (c-AFM) lithography, and transport measurements are performed as a function of the graphene gate voltage. Experiments are performed with devices written adjacent to or directly underneath the graphene gate. Distinct capabilities of this approach include the ability to create highly flexible device configurations, the ability to modulate carrier density at the oxide interface, and the ability to control electron transport up to the single-electron tunneling regime, while maintaining intrinsic transport properties of the oxide interface. Our results facilitate the design of a variety of nanoscale devices that combine excellent transport properties of these two proximal two-dimensional electron systems.
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Affiliation(s)
- Giriraj Jnawali
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
| | - Hyungwoo Lee
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Jung-Woo Lee
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Mengchen Huang
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
| | - Jen-Feng Hsu
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
| | - Feng Bi
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
| | - Rongpu Zhou
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
| | - Guanglei Cheng
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
- CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics , University of Science and Technology of China , Hefei 230026 , China
| | - Brian D'Urso
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
| | - Patrick Irvin
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
| | - Chang-Beom Eom
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Jeremy Levy
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh 15260 , United States
- Pittsburgh Quantum Institute , Pittsburgh , Pennsylvania 15260 , United States
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10
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Pai YY, Tylan-Tyler A, Irvin P, Levy J. Physics of SrTiO 3-based heterostructures and nanostructures: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:036503. [PMID: 29424362 DOI: 10.1088/1361-6633/aa892d] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This review provides a summary of the rich physics expressed within SrTiO3-based heterostructures and nanostructures. The intended audience is researchers who are working in the field of oxides, but also those with different backgrounds (e.g., semiconductor nanostructures). After reviewing the relevant properties of SrTiO3 itself, we will then discuss the basics of SrTiO3-based heterostructures, how they can be grown, and how devices are typically fabricated. Next, we will cover the physics of these heterostructures, including their phase diagram and coupling between the various degrees of freedom. Finally, we will review the rich landscape of quantum transport phenomena, as well as the devices that elicit them.
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Affiliation(s)
- Yun-Yi Pai
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, United States of America. Pittsburgh Quantum Institute, Pittsburgh, PA 15260, United States of America
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11
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Bano A, Gaur NK. Interfacial Coupling Effect on Electron Transport in MoS 2/SrTiO 3 Heterostructure: An Ab-initio Study. Sci Rep 2018; 8:714. [PMID: 29335594 PMCID: PMC5768749 DOI: 10.1038/s41598-017-18984-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 12/15/2017] [Indexed: 11/24/2022] Open
Abstract
A variety of theoretical and experimental works have reported several potential applications of MoS2 monolayer based heterostructures (HSs) such as light emitting diodes, photodetectors and field effect transistors etc. In the present work, we have theoretically performed as a model case study, MoS2 monolayer deposited over insulating SrTiO3 (001) to study the band alignment at TiO2 termination. The interfacial characteristics are found to be highly dependent on the interface termination. With an insulating oxide material, a significant band gap (0.85eV) is found in MoS2/TiO2 interface heterostructure (HS). A unique electronic band profile with an indirect band gap (0.67eV) is observed in MoS2 monolayer when confined in a cubic environment of SrTiO3 (STO). Adsorption analysis showed the chemisorption of MoS2 on the surface of STO substrate with TiO2 termination which is justified by the charge density calculations that shows the existence of covalent bonding at the interface. The fabrication of HS of such materials paves the path for developing the unprecedented 2D materials with exciting properties such as semiconducting devices, thermoelectric and optoelectronic applications.
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Affiliation(s)
- Amreen Bano
- Department of Physics, Barkatullah University, Bhopal, 462026, India.
| | - N K Gaur
- Department of Physics, Barkatullah University, Bhopal, 462026, India
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12
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Niu W, Zhang Y, Gan Y, Christensen DV, Soosten MV, Garcia-Suarez EJ, Riisager A, Wang X, Xu Y, Zhang R, Pryds N, Chen Y. Giant Tunability of the Two-Dimensional Electron Gas at the Interface of γ-Al 2O 3/SrTiO 3. NANO LETTERS 2017; 17:6878-6885. [PMID: 28968124 DOI: 10.1021/acs.nanolett.7b03209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Two-dimensional electron gases (2DEGs) formed at the interface between two oxide insulators provide a rich platform for the next generation of electronic devices. However, their high carrier density makes it rather challenging to control the interface properties under a low electric field through a dielectric solid insulator, that is, in the configuration of conventional field-effect transistors. To surpass this long-standing limit, we used ionic liquids as the dielectric layer for electrostatic gating of oxide interfaces in an electric double layer transistor (EDLT) configuration. Herein, we reported giant tunability of the physical properties of 2DEGs at the spinel/perovskite interface of γ-Al2O3/SrTiO3 (GAO/STO). By modulating the carrier density thus the band filling with ionic-liquid gating, the system experiences a Lifshitz transition at a critical carrier density of 3.0 × 1013 cm-2, where a remarkably strong enhancement of Rashba spin-orbit interaction and an emergence of Kondo effect at low temperatures are observed. Moreover, as the carrier concentration depletes with decreasing gating voltage, the electron mobility is enhanced by more than 6 times in magnitude, leading to the observation of clear quantum oscillations. The great tunability of GAO/STO interface by EDLT gating not only shows promise for design of oxide devices with on-demand properties but also sheds new light on the electronic structure of 2DEG at the nonisostructural spinel/perovskite interface.
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Affiliation(s)
- Wei Niu
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University , 210093 Nanjing, China
| | - Yu Zhang
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Yulin Gan
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Dennis V Christensen
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Merlin V Soosten
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Eduardo J Garcia-Suarez
- Center for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark , 2800 Lyngby, Denmark
| | - Anders Riisager
- Center for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark , 2800 Lyngby, Denmark
| | - Xuefeng Wang
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University , 210093 Nanjing, China
| | - Yongbing Xu
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University , 210093 Nanjing, China
| | - Rong Zhang
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University , 210093 Nanjing, China
| | - Nini Pryds
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
| | - Yunzhong Chen
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
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13
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Zhang L, Zeng S, Yin X, Asmara TC, Yang P, Han K, Cao Y, Zhou W, Wan D, Tang CS, Rusydi A, Venkatesan T. The Mechanism of Electrolyte Gating on High-T c Cuprates: The Role of Oxygen Migration and Electrostatics. ACS NANO 2017; 11:9950-9956. [PMID: 28960953 DOI: 10.1021/acsnano.7b03978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electrolyte gating is widely used to induce large carrier density modulation on solid surfaces to explore various properties. Most of past works have attributed the charge modulation to electrostatic field effect. However, some recent reports have argued that the electrolyte gating effect in VO2, TiO2, and SrTiO3 originated from field-induced oxygen vacancy formation. This gives rise to a controversy about the gating mechanism, and it is therefore vital to reveal the relationship between the role of electrolyte gating and the intrinsic properties of materials. Here, we report entirely different mechanisms of electrolyte gating on two high-Tc cuprates, NdBa2Cu3O7-δ (NBCO) and Pr2-xCexCuO4 (PCCO), with different crystal structures. We show that field-induced oxygen vacancy formation in CuO chains of NBCO plays the dominant role, while it is mainly an electrostatic field effect in the case of PCCO. The possible reason is that NBCO has mobile oxygen in CuO chains, while PCCO does not. Our study helps clarify the controversy relating to the mechanism of electrolyte gating, leading to a better understanding of the role of oxygen electro migration which is very material specific.
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Affiliation(s)
- Lingchao Zhang
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
- Department of Physics, National University of Singapore , Singapore 117551
| | - Shengwei Zeng
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
- Department of Physics, National University of Singapore , Singapore 117551
| | - Xinmao Yin
- Department of Physics, National University of Singapore , Singapore 117551
- Singapore Synchrotron Light Source (SSLS), National University of Singapore , 5 Research Link, Singapore 117603
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University , Shenzhen, China 518060
| | - Teguh Citra Asmara
- Singapore Synchrotron Light Source (SSLS), National University of Singapore , 5 Research Link, Singapore 117603
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore , 5 Research Link, Singapore 117603
| | - Kun Han
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
- Department of Physics, National University of Singapore , Singapore 117551
| | - Yu Cao
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
- Department of Physics, National University of Singapore , Singapore 117551
| | - Wenxiong Zhou
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
- Department of Physics, National University of Singapore , Singapore 117551
| | - Dongyang Wan
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
- Department of Physics, National University of Singapore , Singapore 117551
| | - Chi Sin Tang
- Department of Physics, National University of Singapore , Singapore 117551
- Singapore Synchrotron Light Source (SSLS), National University of Singapore , 5 Research Link, Singapore 117603
- NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore , Singapore 117456
| | - Andrivo Rusydi
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
- Department of Physics, National University of Singapore , Singapore 117551
- Singapore Synchrotron Light Source (SSLS), National University of Singapore , 5 Research Link, Singapore 117603
| | - Thirumalai Venkatesan
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
- Department of Physics, National University of Singapore , Singapore 117551
- NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore , Singapore 117456
- Department of Electrical and Computer Engineering, National University of Singapore , Singapore 117576
- Department of Materials Science and Engineering, National University of Singapore , Singapore 117575
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Oxygen Vacancy in WO 3 Film-based FET with Ionic Liquid Gating. Sci Rep 2017; 7:12253. [PMID: 28947834 PMCID: PMC5612984 DOI: 10.1038/s41598-017-12516-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 08/22/2017] [Indexed: 11/13/2022] Open
Abstract
Ionic liquid gating is a versatile method for inducing a metal-insulator transition in field-effect transistor device structures. The mechanism of carrier doping in metal oxide films is under debate. Ionic liquid gating of a WO3 film-based field effect transistor is discussed in this report. Flat and relatively smooth WO3 films were deposited on SrTiO3 substrates by pulsed laser deposition. Swept and constant gate voltage characteristics are measured in both argon and oxygen atmospheres. The results show a clear dependence on the oxygen pressure of the experimental chamber. Metallic behavior in the films is attributed to oxygen vacancy formation in the WO3 layer induced by the high electric field at the oxide-ionic liquid interface. The density of states of a monoclinic supercell of oxygen deficient WO3 was studied by density functional theory (DFT). Calculated W and O partial densities of states verify metallic behavior even at dilute oxygen vacancy concentrations and show the role of W and O orbitals in the conductivity.
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Sitaputra W, Stacchiola D, Wishart JF, Wang F, Sadowski JT. In Situ Probing of Ion Ordering at an Electrified Ionic Liquid/Au Interface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1606357. [PMID: 28498642 DOI: 10.1002/adma.201606357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/27/2017] [Indexed: 06/07/2023]
Abstract
Charge transport at the interface of electrodes and ionic liquids is critical for the use of the latter as electrolytes. A room-temperature ionic liquid, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide (EMMIM TFSI), is investigated in situ under applied bias voltage with a novel method using low-energy electron and photoemission electron microscopy. Changes in photoelectron yield as a function of bias applied to electrodes provide a direct measure of the dynamics of ion reconfiguration and electrostatic responses of the EMMIM TFSI. Long-range and correlated ionic reconfigurations that occur near the electrodes are found to be a function of temperature and thickness, which, in turn, relate to ionic mobility and different configurations for out-of-plane ordering near the electrode interfaces, with a critical transition in ion mobility for films thicker than three monolayers.
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Affiliation(s)
- Wattaka Sitaputra
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Dario Stacchiola
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - James F Wishart
- Chemistry Division, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Feng Wang
- Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Jerzy T Sadowski
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
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16
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Abstract
The band alignment at an Al2O3/SrTiO3 heterointerface forming a two-dimensional electron gas (2DEG) was investigated using scanning photocurrent microscopy (SPCM) in an electrolyte-gated environment. We used a focused UV laser source for above-the-bandgap illumination on the SrTiO3 layer, creating electron-hole pairs that contributed to the photocurrent through migration towards the metal electrodes. The polarity of the SPCM signals of a bare SrTiO3 device shows typical p-type behavior at zero gate bias, in which the photogenerated electrons are collected by the electrodes. In contrast, the SPCM polarity of 2DEG device indicates that the hole carriers were collected by the metal electrodes. Careful transport measurements revealed that the gate-dependent conductance of the 2DEG devices exhibits n-type switching behavior. More importantly, the SPCM signals in 2DEG devices demonstrated very unique gate-responses that cannot be found in conventional semiconducting devices, based on which we were able to perform detailed investigation into the electronic band alignment of the 2DEG devices and obtain the valence band offset at the heterointerface.
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