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Ohya S, Tsuruoka S, Kaneda M, Shinya H, Fukushima T, Takeda T, Tadano Y, Endo T, Anh LD, Masago A, Katayama-Yoshida H, Tanaka M. Colossal Magnetoresistive Switching Induced by d 0 Ferromagnetism of MgO in a Semiconductor Nanochannel Device with Ferromagnetic Fe/MgO Electrodes. Adv Mater 2024:e2307389. [PMID: 38353134 DOI: 10.1002/adma.202307389] [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] [Received: 07/25/2023] [Revised: 01/08/2024] [Indexed: 03/12/2024]
Abstract
Exploring potential spintronic functionalities in resistive switching (RS) devices is of great interest for creating new applications, such as multifunctional resistive random-access memory and novel neuromorphic computing devices. In particular, the importance of the spin-triplet state of cation vacancies in oxide materials, which is induced by localized and strong O-2p on-site Coulomb interactions, in RS devices has been overlooked. d0 ferromagnetism sometimes appears due to the spin-triplet state and ferromagnetic Zener's double exchange interactions between cation vacancies, which are occasionally strong enough to make nonmagnetic oxides ferromagnetic. Here, for the first time, anomalous and colossal magneto-RS (CMRS) with very high magnetic field dependence is demonstrated by utilizing an unconventional RS device composed of a Ge nanochannel with all-epitaxial single-crystalline Fe/MgO electrodes. The device shows colossal and unusual behavior as the threshold voltage and ON/OFF ratio strongly depend on a magnetic field, which is controllable with an applied voltage. This new phenomenon is attributed to the formation of d0 -ferromagnetic filaments by attractive Mg vacancies due to the spin-triplet states with ferromagnetic double exchange interactions and the ferromagnetic proximity effect of Fe on MgO. The findings will allow the development of energy-efficient CMRS devices with multifield susceptibility.
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Affiliation(s)
- Shinobu Ohya
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Institute for Nano Quantum Information Electronics (NanoQuine), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan
| | - Shun Tsuruoka
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Masaya Kaneda
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Hikari Shinya
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
- Center for Spintronics Research Network (CSRN), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Tetsuya Fukushima
- Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
- Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8560, Japan
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Takahito Takeda
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Yuriko Tadano
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Tatsuro Endo
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Le Duc Anh
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Akira Masago
- Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
- Research Institute for Value-Added-Information Generation, Japan Agency for Marin-Earth Science and Technology, 3173-25 Showa-machi, Yokohama, Kanagawa, 236-0001, Japan
| | - Hiroshi Katayama-Yoshida
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
| | - Masaaki Tanaka
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Institute for Nano Quantum Information Electronics (NanoQuine), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan
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Endo T, Tsuruoka S, Tadano Y, Kaneta-Takada S, Seki Y, Kobayashi M, Anh LD, Seki M, Tabata H, Tanaka M, Ohya S. Giant Spin-Valve Effect in Planar Spin Devices Using an Artificially Implemented Nanolength Mott-Insulator Region. Adv Mater 2023:e2300110. [PMID: 37130792 DOI: 10.1002/adma.202300110] [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] [Received: 01/04/2023] [Revised: 04/24/2023] [Indexed: 05/04/2023]
Abstract
Developing technology to realize oxide-based nanoscale planar integrated circuits is in high demand for next-generation multifunctional electronics. Oxide circuits can have a variety of unique functions, including ferromagnetism, ferroelectricity, multiferroicity, superconductivity, and mechanical flexibility. In particular, for spin-transistor applications, the wide tunability of the physical properties due to the presence of multiple oxide phases is valuable for precise conductivity matching between the channel and ferromagnetic electrodes. This feature is essential for realistic spin-transistor operations. Here, a substantially large magnetoresistance (MR) ratio of up to ∼140% is demonstrated for planar-type (La,Sr)MnO3 (LSMO)-based spin-valve devices. This MR ratio is 10-100 times larger than the best values obtained for semiconductor-based planar devices, which have been studied over the past three decades. This structure is prepared by implementing an artificial nanolength Mott-insulator barrier region using the phase transition of metallic LSMO. The barrier height of the Mott-insulator region is only 55 meV, which enables the large MR ratio. Furthermore, a successful current modulation, which is a fundamental functionality for spin transistors, is shown. These results open up a new avenue for realizing oxide planar circuits with unique functionalities that conventional semiconductors cannot achieve. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tatsuro Endo
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Shun Tsuruoka
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Yuriko Tadano
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Shingo Kaneta-Takada
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Yuichi Seki
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Masaki Kobayashi
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Le Duc Anh
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Munetoshi Seki
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Hitoshi Tabata
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Masaaki Tanaka
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Shinobu Ohya
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
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Datt G, Kotnana G, Maddu R, Vallin Ö, Joshi DC, Peddis D, Barucca G, Kamalakar MV, Sarkar T. Combined Bottom-Up and Top-Down Approach for Highly Ordered One-Dimensional Composite Nanostructures for Spin Insulatronics. ACS Appl Mater Interfaces 2021; 13:37500-37509. [PMID: 34325507 PMCID: PMC8397244 DOI: 10.1021/acsami.1c09582] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Engineering magnetic proximity effects-based devices requires developing efficient magnetic insulators. In particular, insulators, where magnetic phases show dramatic changes in texture on the nanometric level, could allow us to tune the proximity-induced exchange splitting at such distances. In this paper, we report the fabrication and characterization of highly ordered two-dimensional arrays of LaFeO3 (LFO)-CoFe2O4 (CFO) biphasic magnetic nanowires, grown on silicon substrates using a unique combination of bottom-up and top-down synthesis approaches. The regularity of the patterns was confirmed using atomic force microscopy and scanning electron microscopy techniques, whereas magnetic force microscopy images established the magnetic homogeneity of the patterned nanowires and absence of any magnetic debris between the wires. Transmission electron microscopy shows a close spatial correlation between the LFO and CFO phases, indicating strong grain-to-grain interfacial coupling, intrinsically different from the usual core-shell structures. Magnetic hysteresis loops reveal the ferrimagnetic nature of the composites up to room temperature and the presence of a strong magnetic coupling between the two phases, and electrical transport measurements demonstrate the strong insulating behavior of the LFO-CFO composite, which is found to be governed by Mott-variable range hopping conduction mechanisms. A shift in the Raman modes in the composite sample compared to those of pure CFO suggests the existence of strain-mediated elastic coupling between the two phases in the composite sample. Our work offers ordered composite nanowires with strong interfacial coupling between the two phases that can be directly integrated for developing multiphase spin insulatronic devices and emergent magnetic interfaces.
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Affiliation(s)
- Gopal Datt
- Department
of Materials Science and Engineering, Uppsala
University, Box 35, Uppsala SE-751
03, Sweden
| | - Ganesh Kotnana
- Department
of Materials Science and Engineering, Uppsala
University, Box 35, Uppsala SE-751
03, Sweden
| | - Ramu Maddu
- Department
of Materials Science and Engineering, Uppsala
University, Box 35, Uppsala SE-751
03, Sweden
| | - Örjan Vallin
- Department
of Materials Science and Engineering, Uppsala
University, Box 35, Uppsala SE-751
03, Sweden
| | - Deep Chandra Joshi
- Department
of Materials Science and Engineering, Uppsala
University, Box 35, Uppsala SE-751
03, Sweden
| | - Davide Peddis
- Dipartimento
di Chimica e Chimica Industriale, Università
di Genova, Via Dodecaneso
31, Genova I-16146, Italy
- Institute
of Structure of Matter, Italian National
Research Council (CNR), Monterotondo
Scalo, 00015 Rome, Italy
| | - Gianni Barucca
- Department
SIMAU, Università Politecnica delle
Marche, Via Brecce Bianche
12, Ancona 60131, Italy
| | - M. Venkata Kamalakar
- Department
of Physics and Astronomy, Uppsala University, Uppsala SE-751 20, Sweden
| | - Tapati Sarkar
- Department
of Materials Science and Engineering, Uppsala
University, Box 35, Uppsala SE-751
03, Sweden
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Lee MH, Kalcheim Y, Valle JD, Schuller IK. Controlling Metal-Insulator Transitions in Vanadium Oxide Thin Films by Modifying Oxygen Stoichiometry. ACS Appl Mater Interfaces 2021; 13:887-896. [PMID: 33351594 DOI: 10.1021/acsami.0c18327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Vanadium oxides are strongly correlated materials which display metal-insulator transitions (MITs) as well as various structural and magnetic properties that depend heavily on oxygen stoichiometry. Therefore, it is crucial to precisely control oxygen stoichiometry in these materials, especially in thin films. This work demonstrates a high-vacuum gas evolution technique which allows for the modification of oxygen concentrations in VOX thin films by carefully tuning the thermodynamic conditions. We were able to control the evolution between VO2, V3O5, and V2O3 phases on sapphire substrates, overcoming the narrow phase stability of adjacent Magnéli phases. A variety of annealing routes were found to achieve the desired phases and eventually control the MIT. The pronounced MIT of the transformed films along with the detailed structural investigations based on X-ray diffraction measurements and X-ray photoelectron spectroscopy show that optimal stoichiometry is obtained and stabilized. Using this technique, we find that the thin-film V-O phase diagram differs from that of the bulk material because of strain and finite size effects. Our study demonstrates new pathways to strategically tune the oxygen stoichiometry in complex oxides and provides a road map for understanding the phase stability of VOX thin films.
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Affiliation(s)
- Min-Han Lee
- Materials Science and Engineering, University of California San Diego, La Jolla, California 92093, United States
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
| | - Yoav Kalcheim
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
| | - Javier Del Valle
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
| | - Ivan K Schuller
- Materials Science and Engineering, University of California San Diego, La Jolla, California 92093, United States
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, United States
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Caffrey D, Zhussupbekova A, Vijayaraghavan RK, Ainabayev A, Kaisha A, Sugurbekova G, Shvets IV, Fleischer K. Crystallographic Characterisation of Ultra-Thin, or Amorphous Transparent Conducting Oxides-The Case for Raman Spectroscopy. Materials (Basel) 2020; 13:ma13020267. [PMID: 31936137 PMCID: PMC7013887 DOI: 10.3390/ma13020267] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/31/2019] [Accepted: 01/02/2020] [Indexed: 01/31/2023]
Abstract
The electronic and optical properties of transparent conducting oxides (TCOs) are closely linked to their crystallographic structure on a macroscopic (grain sizes) and microscopic (bond structure) level. With the increasing drive towards using reduced film thicknesses in devices and growing interest in amorphous TCOs such as n-type InGaZnO4 (IGZO), ZnSnO3 (ZTO), p-type CuxCrO2, or ZnRh2O4, the task of gaining in-depth knowledge on their crystal structure by conventional X-ray diffraction-based measurements are becoming increasingly difficult. We demonstrate the use of a focal shift based background subtraction technique for Raman spectroscopy specifically developed for the case of transparent thin films on amorphous substrates. Using this technique we demonstrate, for a variety of TCOs CuO, a-ZTO, ZnO:Al), how changes in local vibrational modes reflect changes in the composition of the TCO and consequently their electronic properties.
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Affiliation(s)
- David Caffrey
- School of Physics, Trinity College, The University of Dublin, Dublin 2, Ireland; (D.C.)
| | - Ainur Zhussupbekova
- School of Physics, Trinity College, The University of Dublin, Dublin 2, Ireland; (D.C.)
| | | | - Ardak Ainabayev
- School of Physics, Trinity College, The University of Dublin, Dublin 2, Ireland; (D.C.)
- Nazarbayev University, Laboratory of Materials Processing and Applied Physics, Nur-Sultan 010000, Kazakhstan
| | - Aitkazy Kaisha
- School of Physics, Trinity College, The University of Dublin, Dublin 2, Ireland; (D.C.)
| | - Gulnar Sugurbekova
- Nazarbayev University, Laboratory of Materials Processing and Applied Physics, Nur-Sultan 010000, Kazakhstan
| | - Igor V. Shvets
- School of Physics, Trinity College, The University of Dublin, Dublin 2, Ireland; (D.C.)
| | - Karsten Fleischer
- School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland
- Correspondence: ; Tel.: +353-1-700-5038
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Cadilha Marques G, Weller D, Erozan AT, Feng X, Tahoori M, Aghassi-Hagmann J. Progress Report on "From Printed Electrolyte-Gated Metal-Oxide Devices to Circuits". Adv Mater 2019; 31:e1806483. [PMID: 30891821 DOI: 10.1002/adma.201806483] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 12/06/2018] [Indexed: 06/09/2023]
Abstract
Printed electrolyte-gated oxide electronics is an emerging electronic technology in the low voltage regime (≤1 V). Whereas in the past mainly dielectrics have been used for gating the transistors, many recent approaches employ the advantages of solution processable, solid polymer electrolytes, or ion gels that provide high gate capacitances produced by a Helmholtz double layer, allowing for low-voltage operation. Herein, with special focus on work performed at KIT recent advances in building electronic circuits based on indium oxide, n-type electrolyte-gated field-effect transistors (EGFETs) are reviewed. When integrated into ring oscillator circuits a digital performance ranging from 250 Hz at 1 V up to 1 kHz is achieved. Sequential circuits such as memory cells are also demonstrated. More complex circuits are feasible but remain challenging also because of the high variability of the printed devices. However, the device inherent variability can be even exploited in security circuits such as physically unclonable functions (PUFs), which output a reliable and unique, device specific, digital response signal. As an overall advantage of the technology all the presented circuits can operate at very low supply voltages (0.6 V), which is crucial for low-power printed electronics applications.
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Affiliation(s)
- Gabriel Cadilha Marques
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Chair of Dependable Nano Computing (CDNC), Department of Computer Science, Karlsruhe Institute of Technology (KIT), Haid-und-Neu-Str. 7, 76131, Karlsruhe, Germany
| | - Dennis Weller
- Chair of Dependable Nano Computing (CDNC), Department of Computer Science, Karlsruhe Institute of Technology (KIT), Haid-und-Neu-Str. 7, 76131, Karlsruhe, Germany
| | - Ahmet Turan Erozan
- Chair of Dependable Nano Computing (CDNC), Department of Computer Science, Karlsruhe Institute of Technology (KIT), Haid-und-Neu-Str. 7, 76131, Karlsruhe, Germany
| | - Xiaowei Feng
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Department of Electrical Engineering and Information Technology, Offenburg University of Applied Sciences, Badstr. 24, 77652, Offenburg, Germany
| | - Mehdi Tahoori
- Chair of Dependable Nano Computing (CDNC), Department of Computer Science, Karlsruhe Institute of Technology (KIT), Haid-und-Neu-Str. 7, 76131, Karlsruhe, Germany
| | - Jasmin Aghassi-Hagmann
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Department of Electrical Engineering and Information Technology, Offenburg University of Applied Sciences, Badstr. 24, 77652, Offenburg, Germany
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Chen Y, Huang W, Sangwan VK, Wang B, Zeng L, Wang G, Huang Y, Lu Z, Bedzyk MJ, Hersam MC, Marks TJ, Facchetti A. Polymer Doping Enables a Two-Dimensional Electron Gas for High-Performance Homojunction Oxide Thin-Film Transistors. Adv Mater 2019; 31:e1805082. [PMID: 30499146 DOI: 10.1002/adma.201805082] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/10/2018] [Indexed: 05/04/2023]
Abstract
High-performance solution-processed metal oxide (MO) thin-film transistors (TFTs) are realized by fabricating a homojunction of indium oxide (In2 O3 ) and polyethylenimine (PEI)-doped In2 O3 (In2 O3 :x% PEI, x = 0.5-4.0 wt%) as the channel layer. A two-dimensional electron gas (2DEG) is thereby achieved by creating a band offset between the In2 O3 and PEI-In2 O3 via work function tuning of the In2 O3 :x% PEI, from 4.00 to 3.62 eV as the PEI content is increased from 0.0 (pristine In2 O3 ) to 4.0 wt%, respectively. The resulting devices achieve electron mobilities greater than 10 cm2 V-1 s-1 on a 300 nm SiO2 gate dielectric. Importantly, these metrics exceed those of the devices composed of the pristine In2 O3 materials, which achieve a maximum mobility of ≈4 cm2 V-1 s-1 . Furthermore, a mobility as high as 30 cm2 V-1 s-1 is achieved on a high-k ZrO2 dielectric in the homojunction devices. This is the first demonstration of 2DEG-based homojunction oxide TFTs via band offset achieved by simple polymer doping of the same MO material.
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Affiliation(s)
- Yao Chen
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, P. R. China
| | - Wei Huang
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Vinod K Sangwan
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Binghao Wang
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Li Zeng
- Applied Physics Program and the Materials Research Center, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Gang Wang
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Yan Huang
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, P. R. China
| | - Zhiyun Lu
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, P. R. China
| | - Michael J Bedzyk
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
- Applied Physics Program and the Materials Research Center, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Tobin J Marks
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering and the Argonne Northwestern Solar Energy Research Center (ANSER), Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Antonio Facchetti
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
- Flexterra Inc., 8025 Lamon Avenue, Skokie, IL, 60077, USA
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8
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Zhang L, Yuan Y, Lapano J, Brahlek M, Lei S, Kabius B, Gopalan V, Engel-Herbert R. Continuously Tuning Epitaxial Strains by Thermal Mismatch. ACS Nano 2018; 12:1306-1312. [PMID: 29320634 DOI: 10.1021/acsnano.7b07539] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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
Strain engineering of thin films is a conventionally employed approach to enhance material properties and to energetically prefer ground states that would otherwise not be attainable. Controlling strain states in perovskite oxide thin films is usually accomplished through coherent epitaxy by using lattice-mismatched substrates with similar crystal structures. However, the limited choice of suitable oxide substrates makes certain strain states experimentally inaccessible and a continuous tuning impossible. Here, we report a strategy to continuously tune epitaxial strains in perovskite films grown on Si(001) by utilizing the large difference of thermal expansion coefficients between the film and the substrate. By establishing an adsorption-controlled growth window for SrTiO3 thin films on Si using hybrid molecular beam epitaxy, the magnitude of strain can be solely attributed to thermal expansion mismatch, which only depends on the difference between growth and room temperature. Second-harmonic generation measurements revealed that structure properties of SrTiO3 films could be tuned by this method using films with different strain states. Our work provides a strategy to generate continuous strain states in oxide/semiconductor pseudomorphic buffer structures that could help achieve desired material functionalities.
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Affiliation(s)
- Lei Zhang
- Department of Materials Science and Engineering, ‡Materials Research Institute, §Department of Physics, and ∥Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Yakun Yuan
- Department of Materials Science and Engineering, ‡Materials Research Institute, §Department of Physics, and ∥Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Jason Lapano
- Department of Materials Science and Engineering, ‡Materials Research Institute, §Department of Physics, and ∥Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Matthew Brahlek
- Department of Materials Science and Engineering, ‡Materials Research Institute, §Department of Physics, and ∥Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Shiming Lei
- Department of Materials Science and Engineering, ‡Materials Research Institute, §Department of Physics, and ∥Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Bernd Kabius
- Department of Materials Science and Engineering, ‡Materials Research Institute, §Department of Physics, and ∥Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Venkatraman Gopalan
- Department of Materials Science and Engineering, ‡Materials Research Institute, §Department of Physics, and ∥Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Roman Engel-Herbert
- Department of Materials Science and Engineering, ‡Materials Research Institute, §Department of Physics, and ∥Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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9
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Abstract
The use of thermally stable Sr2RuO4 electrodes in high-temperature synthesis of oxide heterostructures was investigated. Atomically smooth Sr2RuO4 thin films were grown on SrTiO3(001) substrates by pulsed laser deposition and used as a bottom electrode for ferroelectric BaTiO3 capacitors grown at temperatures of up to 1000 °C. The thermal stability of Sr2RuO4 electrodes was verified by structural and electrical measurements of the ferroelectric BaTiO3 films. The best growth temperature for the BaTiO3 films was found to be 900 °C, exhibiting the largest spontaneous polarization, dielectric constant, and pyroelectric response. We conclude that Sr2RuO4 films are suitable for use as thermally stable electrodes in heterostructures synthesized at temperatures up to at least 1000 °C and oxygen pressures from 10-6 to 10-1 Torr. This range of growth film conditions is much wider than that for other common oxide electrode materials such as SrRuO3, widening the available process window for optimizing the performance of oxide electronic devices.
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Affiliation(s)
- Ryota Takahashi
- Institute for Solid State Physics, University of Tokyo , Chiba 277-8581, Japan
- JST PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Mikk Lippmaa
- Institute for Solid State Physics, University of Tokyo , Chiba 277-8581, Japan
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10
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Yamin T, Wissberg S, Cohen H, Cohen-Taguri G, Sharoni A. Ultrathin Films of VO2 on r-Cut Sapphire Achieved by Postdeposition Etching. ACS Appl Mater Interfaces 2016; 8:14863-14870. [PMID: 27183029 DOI: 10.1021/acsami.6b02859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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
The metal-insulator transition (MIT) properties of correlated oxides thin films, such as VO2, are dramatically affected by strain induced at the interface with the substrate, which usually changes with deposition thickness. For VO2 grown on r-cut sapphire, there is a minimum deposition thickness required for a significant MIT to appear, around 60 nm. We show that in these thicker films an interface layer develops, which accompanies the relaxation of film strain and enhanced electronic transition. If these interface dislocations are stable at room temperature, we conjectured, a new route opens to control thickness of VO2 films by postdeposition thinning of relaxed films, overcoming the need for thickness-dependent strain-engineered substrates. This is possible only if thinning does not alter the films' electronic properties. We find that wet etching in a dilute NaOH solution can effectively thin the VO2 films, which continue to show a significant MIT, even when etched to 10 nm, for which directly deposited films show nearly no transition. The structural and chemical composition were not modified by the etching, but the grain size and film roughness were, which modified the hysteresis width and magnitude of the MIT resistance change.
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Affiliation(s)
| | | | - Hagai Cohen
- Department of Chemical Research Support, Weizmann Institute of Science , Rehovot, Israel IL-76100
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11
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Baby TT, Garlapati SK, Dehm S, Häming M, Kruk R, Hahn H, Dasgupta S. A general route toward complete room temperature processing of printed and high performance oxide electronics. ACS Nano 2015; 9:3075-3083. [PMID: 25693653 DOI: 10.1021/nn507326z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Critical prerequisites for solution-processed/printed field-effect transistors (FETs) and logics are excellent electrical performance including high charge carrier mobility, reliability, high environmental stability and low/preferably room temperature processing. Oxide semiconductors can often fulfill all the above criteria, sometimes even with better promise than their organic counterparts, except for their high process temperature requirement. The need for high annealing/curing temperatures renders oxide FETs rather incompatible to inexpensive, flexible substrates, which are commonly used for high-throughput and roll-to-roll additive manufacturing techniques, such as printing. To overcome this serious limitation, here we demonstrate an alternative approach that enables completely room-temperature processing of printed oxide FETs with device mobility as large as 12.5 cm(2)/(V s). The key aspect of the present concept is a chemically controlled curing process of the printed nanoparticle ink that provides surprisingly dense thin films and excellent interparticle electrical contacts. In order to demonstrate the versatility of this approach, both n-type (In2O3) and p-type (Cu2O) oxide semiconductor nanoparticle dispersions are prepared to fabricate, inkjet printed and completely room temperature processed, all-oxide complementary metal oxide semiconductor (CMOS) invertors that can display significant signal gain (∼18) at a supply voltage of only 1.5 V.
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Affiliation(s)
- Tessy T Baby
- †Institute for Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- ‡Helmholtz Institute Ulm (HIU), Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Suresh K Garlapati
- †Institute for Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- §KIT-TUD Joint Research Laboratory Nanomaterials, Technische Universität Darmstadt (TUD), Institute of Materials Science, Jovanka-Bontschits-Str. 2, 64287 Darmstadt, Germany
| | - Simone Dehm
- †Institute for Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Marc Häming
- ⊥Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Robert Kruk
- †Institute for Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Horst Hahn
- †Institute for Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- ‡Helmholtz Institute Ulm (HIU), Albert-Einstein-Allee 11, 89081 Ulm, Germany
- §KIT-TUD Joint Research Laboratory Nanomaterials, Technische Universität Darmstadt (TUD), Institute of Materials Science, Jovanka-Bontschits-Str. 2, 64287 Darmstadt, Germany
| | - Subho Dasgupta
- †Institute for Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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Chen Y, Trier F, Kasama T, Christensen DV, Bovet N, Balogh ZI, Li H, Thydén KTS, Zhang W, Yazdi S, Norby P, Pryds N, Linderoth S. Creation of high mobility two-dimensional electron gases via strain induced polarization at an otherwise nonpolar complex oxide interface. Nano Lett 2015; 15:1849-1854. [PMID: 25692804 DOI: 10.1021/nl504622w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The discovery of two-dimensional electron gases (2DEGs) in SrTiO3-based heterostructures provides new opportunities for nanoelectronics. Herein, we create a new type of oxide 2DEG by the epitaxial-strain-induced polarization at an otherwise nonpolar perovskite-type interface of CaZrO3/SrTiO3. Remarkably, this heterointerface is atomically sharp and exhibits a high electron mobility exceeding 60,000 cm(2) V(-1) s(-1) at low temperatures. The 2DEG carrier density exhibits a critical dependence on the film thickness, in good agreement with the polarization induced 2DEG scheme.
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Affiliation(s)
- Yunzhong Chen
- Department of Energy Conversion and Storage, Technical University of Denmark , Risø Campus, 4000 Roskilde, Denmark
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Moyer JA, Eaton C, Engel-Herbert R. Highly Conductive SrVO3 as a bottom electrode for functional perovskite oxides. Adv Mater 2013; 25:3578-3582. [PMID: 23703901 DOI: 10.1002/adma.201300900] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/10/2013] [Indexed: 06/02/2023]
Abstract
Stoichiometric SrVO3 thin films grown by hybrid molecular beam epitaxy are demonstrated, meeting the stringent requirements of an ideal bottom electrode material. They display an order of magnitude lower room temperature resistivity and superior chemical stability, compared to the commonly employed SrRuO3 , as well as atomically smooth surfaces. Excellent structural compatibility with perovskite and related structures renders SrVO3 a high performance electrode material with the potential to promote the creation of new functional oxide electronic devices.
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Affiliation(s)
- Jarrett A Moyer
- Department of Physics, Pennsylvania State University, University Park, PA 16802, USA
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