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Chatterjee A, Lan Z, Christensen DV, Bauitti F, Morata A, Chavez-Angel E, Sanna S, Castelli IE, Chen Y, Tarancon A, Pryds N. On the thermoelectric properties of Nb-doped SrTiO 3 epitaxial thin films. Phys Chem Chem Phys 2022; 24:3741-3748. [PMID: 35080541 DOI: 10.1039/d1cp03679c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The exploration for thermoelectric thin films of complex oxides such as SrTiO3-based oxides is driven by the need for miniaturized harvesting devices for powering the Internet of Things (IoT). However, there is still not a clear consensus in the literature for the underlying influence of film thickness on thermoelectric properties. Here, we report the fabrication of epitaxial thin films of 6% Nb-doped SrTiO3 on (001) (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) single crystal using pulsed laser deposition (PLD) where the film thickness was varied from 2 nm to 68 nm. The thickness dependence shows a subtle increase of tetragonality of the thin film lattice and a gradual drop of the electrical conductivity, the density of charge carriers, and the thermoelectric Seebeck coefficient as the film thickness decreases. DFT-based calculations show that ∼2.8% increase in tetragonality results in an increased splitting between t2g and eg orbitals to ∼42.3 meV. However, experimentally observed tetragonality for films between 68 to 13 nm is only 0.06%. Hence, the effect of thickness on tetragonality is neglected. We have discussed the decrease of conductivity and the Seebeck coefficient based on the decrease of carriers and change in the scattering mechanism, respectively.
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Affiliation(s)
- Arindom Chatterjee
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs Lyngby, Denmark.
| | - Zhenyun Lan
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs Lyngby, Denmark.
| | | | - Federico Bauitti
- Catalonia Institute for Energy Research (IREC), Jardins de Les Dones de Negre 1, 08930 Sant Adrià Besos, Barcelona, Spain
| | - Alex Morata
- Catalonia Institute for Energy Research (IREC), Jardins de Les Dones de Negre 1, 08930 Sant Adrià Besos, Barcelona, Spain
| | - Emigdio Chavez-Angel
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), and Barcelona Institute of Science and Technology (BIST), Bellaterra-08193, Spain
| | - Simone Sanna
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs Lyngby, Denmark. .,Università degli Studi di Roma Tor Vergata and CNR-SPIN Rome, Department of Civil Engineering and Computer Science, Università di Roma Tor Vergata Dipartimento di Ingegneria Civile e Ingegneria Informatica DICII, Via del Politecnico-1, I - 00133, Roma, Italy
| | - Ivano E Castelli
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs Lyngby, Denmark.
| | - Yunzhong Chen
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs Lyngby, Denmark.
| | - Albert Tarancon
- Catalonia Institute for Energy Research (IREC), Jardins de Les Dones de Negre 1, 08930 Sant Adrià Besos, Barcelona, Spain.,ICREA, 23 Passeig Lluís Companys, Barcelona 08010, Spain
| | - Nini Pryds
- Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs Lyngby, Denmark.
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Rose MA, Barnett J, Wendland D, Hensling FVE, Boergers JM, Moors M, Dittmann R, Taubner T, Gunkel F. Local inhomogeneities resolved by scanning probe techniques and their impact on local 2DEG formation in oxide heterostructures. NANOSCALE ADVANCES 2021; 3:4145-4155. [PMID: 36132831 PMCID: PMC9419657 DOI: 10.1039/d1na00190f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/02/2021] [Indexed: 06/16/2023]
Abstract
Lateral inhomogeneities in the formation of two-dimensional electron gases (2DEG) directly influence their electronic properties. Understanding their origin is an important factor for fundamental interpretations, as well as high quality devices. Here, we studied the local formation of the buried 2DEG at LaAlO3/SrTiO3 (LAO/STO) interfaces grown on STO (100) single crystals with partial TiO2 termination, utilizing in situ conductive atomic force microscopy (c-AFM) and scattering-type scanning near-field optical microscopy (s-SNOM). Using substrates with different degrees of chemical surface termination, we can link the resulting interface chemistry to an inhomogeneous 2DEG formation. In conductivity maps recorded by c-AFM, a significant lack of conductivity is observed at topographic features, indicative of a local SrO/AlO2 interface stacking order, while significant local conductivity can be probed in regions showing TiO2/LaO interface stacking order. These results could be corroborated by s-SNOM, showing a similar contrast distribution in the optical signal which can be linked to the local electronic properties of the material. The results are further complemented by low-temperature conductivity measurements, which show an increasing residual resistance at 5 K with increasing portion of insulating SrO-terminated areas. Therefore, we can correlate the macroscopic electrical behavior of our samples to their nanoscopic structure. Using proper parameters, 2DEG mapping can be carried out without any visible alteration of sample properties, proving c-AFM and s-SNOM to be viable and destruction-free techniques for the identification of local 2DEG formation. Furthermore, applying c-AFM and s-SNOM in this manner opens the exciting prospect to link macroscopic low-temperature transport to its nanoscopic origin.
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Affiliation(s)
- M-A Rose
- Institute of Electronic Materials (IWE II), RWTH Aachen University Aachen Germany
- Peter Gruenberg Institute, JARA-FIT, Forschungszentrum Juelich GmbH Juelich Germany
| | - J Barnett
- I. Institute of Physics (IA), RWTH Aachen University Aachen Germany
| | - D Wendland
- I. Institute of Physics (IA), RWTH Aachen University Aachen Germany
| | - F V E Hensling
- Peter Gruenberg Institute, JARA-FIT, Forschungszentrum Juelich GmbH Juelich Germany
| | - J M Boergers
- Peter Gruenberg Institute, JARA-FIT, Forschungszentrum Juelich GmbH Juelich Germany
| | - M Moors
- Peter Gruenberg Institute, JARA-FIT, Forschungszentrum Juelich GmbH Juelich Germany
| | - R Dittmann
- Peter Gruenberg Institute, JARA-FIT, Forschungszentrum Juelich GmbH Juelich Germany
| | - T Taubner
- I. Institute of Physics (IA), RWTH Aachen University Aachen Germany
| | - F Gunkel
- Institute of Electronic Materials (IWE II), RWTH Aachen University Aachen Germany
- Peter Gruenberg Institute, JARA-FIT, Forschungszentrum Juelich GmbH Juelich Germany
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Munjal S, Khare N. Compliance current controlled volatile and nonvolatile memory in Ag/CoFe 2O 4/Pt resistive switching device. NANOTECHNOLOGY 2021; 32:185204. [PMID: 33470980 DOI: 10.1088/1361-6528/abdd5f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report on the resistive memory effects of a Ag/CoFe2O4/Pt device and a deterministic conversion between volatile and nonvolatile resistive switching (RS) memory through the tuning of current compliance (I CC). For the smaller I CC (10-4 A) the device exhibits volatile RS behavior with an atomically sized conducting filament showing the quantum conductance. For an intermediate I CC (10-2 A) nonvolatile bipolar RS behavior is observed, which could originate from the formation and rupture of filament consisting of Ag ions. The high resistance state (HRS) of the device shows a semiconducting conduction mechanism, whereas the low resistance state (LRS) was found to be Ohmic in nature. The temperature dependent resistance studies and magnetization studies indicated that the electrochemical metallization plays a dominant role in the resistive switching process for volatile and nonvolatile modes through the formation of Ag conducting filaments. For higher I CC (10-1 A) the device permanently switches to LRS. The irreversible RS memory behaviors, observed for higher I CC, could be attributed to the formation of a thick and stable conducting channel formed of oxygen vacancies and Ag ions. The compliance current controlled resistive switching modes with a large memory window make the present device a potential candidate to pave the way for future resistive switching devices.
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Affiliation(s)
- Sandeep Munjal
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016, India
| | - Neeraj Khare
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016, India
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Park HL, Lee Y, Kim N, Seo DG, Go GT, Lee TW. Flexible Neuromorphic Electronics for Computing, Soft Robotics, and Neuroprosthetics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1903558. [PMID: 31559670 DOI: 10.1002/adma.201903558] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/10/2019] [Indexed: 05/08/2023]
Abstract
Flexible neuromorphic electronics that emulate biological neuronal systems constitute a promising candidate for next-generation wearable computing, soft robotics, and neuroprosthetics. For realization, with the achievement of simple synaptic behaviors in a single device, the construction of artificial synapses with various functions of sensing and responding and integrated systems to mimic complicated computing, sensing, and responding in biological systems is a prerequisite. Artificial synapses that have learning ability can perceive and react to events in the real world; these abilities expand the neuromorphic applications toward health monitoring and cybernetic devices in the future Internet of Things. To demonstrate the flexible neuromorphic systems successfully, it is essential to develop artificial synapses and nerves replicating the functionalities of the biological counterparts and satisfying the requirements for constructing the elements and the integrated systems such as flexibility, low power consumption, high-density integration, and biocompatibility. Here, the progress of flexible neuromorphic electronics is addressed, from basic backgrounds including synaptic characteristics, device structures, and mechanisms of artificial synapses and nerves, to applications for computing, soft robotics, and neuroprosthetics. Finally, future research directions toward wearable artificial neuromorphic systems are suggested for this emerging area.
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Affiliation(s)
- Hea-Lim Park
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Yeongjun Lee
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- BK21 PLUS SNU Materials Division for Educating Creative Global Leaders, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Naryung Kim
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Dae-Gyo Seo
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Gyeong-Tak Go
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Tae-Woo Lee
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- BK21 PLUS SNU Materials Division for Educating Creative Global Leaders, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Institute of Engineering Research Research Institute of Advanced Materials, Nano Systems Institute (NSI), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
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Toward a generalized Bienenstock-Cooper-Munro rule for spatiotemporal learning via triplet-STDP in memristive devices. Nat Commun 2020; 11:1510. [PMID: 32198368 PMCID: PMC7083931 DOI: 10.1038/s41467-020-15158-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 02/12/2020] [Indexed: 11/08/2022] Open
Abstract
The close replication of synaptic functions is an important objective for achieving a highly realistic memristor-based cognitive computation. The emulation of neurobiological learning rules may allow the development of neuromorphic systems that continuously learn without supervision. In this work, the Bienenstock-Cooper-Munro learning rule, as a typical case of spike-rate-dependent plasticity, is mimicked using a generalized triplet-spike-timing-dependent plasticity scheme in a WO3-x memristive synapse. It demonstrates both presynaptic and postsynaptic activities and remedies the absence of the enhanced depression effect in the depression region, allowing a better description of the biological counterpart. The threshold sliding effect of Bienenstock-Cooper-Munro rule is realized using a history-dependent property of the second-order memristor. Rate-based orientation selectivity is demonstrated in a simulated feedforward memristive network with this generalized Bienenstock-Cooper-Munro framework. These findings provide a feasible approach for mimicking Bienenstock-Cooper-Munro learning rules in memristors, and support the applications of spatiotemporal coding and learning using memristive networks.
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You T, Huang K, Zhao X, Yi A, Chen C, Ren W, Jin T, Lin J, Shuai Y, Luo W, Zhou M, Yu W, Ou X. Engineering of self-rectifying filamentary resistive switching in LiNbO 3 single crystalline thin film via strain doping. Sci Rep 2019; 9:19134. [PMID: 31836794 PMCID: PMC6911103 DOI: 10.1038/s41598-019-55628-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 11/27/2019] [Indexed: 11/09/2022] Open
Abstract
The abilities to fabricate wafer scale single crystalline oxide thin films on metallic substrates and to locally engineer their resistive switching characteristics not only contribute to the fundamental investigations of the resistive switching mechanism but also promote the practical applications of resistive switching devices. Here, wafer scale LiNbO3 (LNO) single crystalline thin films are fabricated on Pt/SiO2/LNO substrates by ion slicing with wafer bonding. The lattice strain of the LNO single crystalline thin films can be tuned by He implantation as indicated by XRD measurements. After He implantation, the LNO single crystalline thin films show self-rectifying filamentary resistive switching behaviors, which is interpreted by a model that the local conductive filaments only connect/disconnect with the bottom interface while the top interface maintains the Schottky contact. Thanks to the homogeneous distribution of defects in single crystalline thin films, highly reproducible and uniform self-rectifying resistive switching with large on/off ratio over four order of magnitude was achieved. Multilevel resistive switching can be obtained by varying the compliance current or by using different magnitude of writing voltage.
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Affiliation(s)
- Tiangui You
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Kai Huang
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Xiaomeng Zhao
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Ailun Yi
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Chen Chen
- Department of Physics, Shanghai University, Shanghai, 200444, P. R. China
| | - Wei Ren
- Department of Physics, Shanghai University, Shanghai, 200444, P. R. China
| | - Tingting Jin
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Jiajie Lin
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Yao Shuai
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Wenbo Luo
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Min Zhou
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Wenjie Yu
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Xin Ou
- State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China.
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7
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Ahmed T, Walia S, Mayes ELH, Ramanathan R, Bansal V, Bhaskaran M, Sriram S, Kavehei O. Time and rate dependent synaptic learning in neuro-mimicking resistive memories. Sci Rep 2019; 9:15404. [PMID: 31659247 PMCID: PMC6817848 DOI: 10.1038/s41598-019-51700-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 10/01/2019] [Indexed: 12/27/2022] Open
Abstract
Memristors have demonstrated immense potential as building blocks in future adaptive neuromorphic architectures. Recently, there has been focus on emulating specific synaptic functions of the mammalian nervous system by either tailoring the functional oxides or engineering the external programming hardware. However, high device-to-device variability in memristors induced by the electroforming process and complicated programming hardware are among the key challenges that hinder achieving biomimetic neuromorphic networks. Here, a simple hybrid complementary metal oxide semiconductor (CMOS)-memristor approach is reported to implement different synaptic learning rules by utilizing a CMOS-compatible memristor based on oxygen-deficient SrTiO3-x (STOx). The potential of such hybrid CMOS-memristor approach is demonstrated by successfully imitating time-dependent (pair and triplet spike-time-dependent-plasticity) and rate-dependent (Bienenstosk-Cooper-Munro) synaptic learning rules. Experimental results are benchmarked against in-vitro measurements from hippocampal and visual cortices with good agreement. The scalability of synaptic devices and their programming through a CMOS drive circuitry elaborates the potential of such an approach in realizing adaptive neuromorphic computation and networks.
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Affiliation(s)
- Taimur Ahmed
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia.
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia.
| | - Sumeet Walia
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia
| | - Edwin L H Mayes
- RMIT Microscopy and Microanalysis Facility, RMIT University, Melbourne, VIC, 3001, Australia
| | - Rajesh Ramanathan
- Sir Ian Potter NanoBioSensing Facility, NanoBiotechnology Research Laboratory, School of Science, RMIT University, Melbourne, VIC, 3001, Australia
| | - Vipul Bansal
- Sir Ian Potter NanoBioSensing Facility, NanoBiotechnology Research Laboratory, School of Science, RMIT University, Melbourne, VIC, 3001, Australia
| | - Madhu Bhaskaran
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia.
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia.
| | - Omid Kavehei
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia.
- Functional Materials and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, VIC, 3001, Australia.
- Faculty of Engineering, The University of Sydney, NWS, 2006, Sydney, Australia.
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Gao S, Liu G, Yang H, Hu C, Chen Q, Gong G, Xue W, Yi X, Shang J, Li RW. An Oxide Schottky Junction Artificial Optoelectronic Synapse. ACS NANO 2019; 13:2634-2642. [PMID: 30730696 DOI: 10.1021/acsnano.9b00340] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The rapid development of artificial intelligence techniques and future advanced robot systems sparks emergent demand on the accurate perception and understanding of the external environments via visual sensing systems that can co-locate the self-adaptive detecting, processing, and memorizing of optical signals. In this contribution, a simple indium-tin oxide/Nb-doped SrTiO3 (ITO/Nb:SrTiO3) heterojunction artificial optoelectronic synapse is proposed and demonstrated. Through the light and electric field co-modulation of the Schottky barrier profile at the ITO/Nb:SrTiO3 interface, the oxide heterojunction device can respond to the entire visible light region in a neuromorphic manner, allowing synaptic paired-pulse facilitation, short/long-term memory, and "learning-experience" behavior for optical information manipulation. More importantly, the photoplasticity of the artificial synapse has been modulated by heterosynaptic means with a sub-1 V external voltage, not only enabling an optoelectronic analog of the mechanical aperture device showing adaptive and stable optical perception capability under different illuminating conditions but also making the artificial synapse suitable for the mimicry of interest-modulated human visual memories.
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Affiliation(s)
- Shuang Gao
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Gang Liu
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Huali Yang
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Chao Hu
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Qilai Chen
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Guodong Gong
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Wuhong Xue
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Xiaohui Yi
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Jie Shang
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
| | - Run-Wei Li
- CAS Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo , Zhejiang 315201 , China
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Waser R, Dittmann R, Menzel S, Noll T. Introduction to new memory paradigms: memristive phenomena and neuromorphic applications. Faraday Discuss 2019; 213:11-27. [PMID: 30740612 DOI: 10.1039/c8fd90058b] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article provides a brief introduction to the Faraday Discussion "New memory paradigms: memristive phenomena and neuromorphic applications" held in Aachen, Germany, 15-17 October 2018. It will cover basic definitions of memristive switching elements, their main switching modes, and their most important performance parameters as well as applications in neuromorphic computing. The article comprises parts from the following sources: General Introduction and Introduction to Part V of Nanoelectronics and Information Technology, ed. R. Waser, Wiley-VCH, 2012; Chapter 4 of Nanotechnology: Volume 3: Information Technology I, ed. R. Waser, Wiley-VCH, Weinheim, 2008; Chapters 3-9 of Emerging Nanoelectronic Devices, ed. A. Chen, J. Hutchby, V. Zhirnov and G. Bourianoff, Wiley, 2015; Chapter 1 of Resistive Switching, ed. D. Ielmini and R. Waser, Wiley-VCH, 2016 (with permission by Wiley-VCH).
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Affiliation(s)
- Rainer Waser
- Peter Gruenberg Institute 7, Forschungszentrum Juelich GmbH and JARA-FIT, 52425 Juelich, Germany
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10
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Baeumer C, Heisig T, Arndt B, Skaja K, Borgatti F, Offi F, Motti F, Panaccione G, Waser R, Menzel S, Dittmann R. Spectroscopic elucidation of ionic motion processes in tunnel oxide-based memristive devices. Faraday Discuss 2019; 213:215-230. [PMID: 30364919 DOI: 10.1039/c8fd00108a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Resistive switching oxides are highly attractive candidates to emulate synaptic behaviour in artificial neural networks. Whilst the most widely employed systems exhibit filamentary resistive switching, interface-type switching systems based on a tunable tunnel barrier are of increasing interest, since their gradual SET and RESET processes provide an analogue-type of switching required to take over synaptic functionality. Interface-type switching devices often consist of bilayers of one highly mixed-conductive oxide layer and one highly insulating tunnel oxide layer. However, most tunnel oxides used for interface-type switching are also prone to form conducting filaments above a certain voltage bias threshold. We investigated two different tunnel oxide devices, namely, Pr1-xCaxMnO3 (PCMO) with yttria-stabilized ZrO2 (YSZ) tunnel barrier and substoichiometric TaOx with HfO2 tunnel barrier by interface-sensitive, hard X-ray photoelectron spectroscopy (HAXPES) in order to gain insights into the chemical changes during filamentary and interface-type switching. The measurements suggest an exchange of oxygen ions between the mixed conducting oxide layer and the tunnel barrier, that causes an electrostatic modulation of the effective height of the tunnel barrier, as the underlying switching mechanism for the interface-type switching. Moreover, we observe by in operando HAXPES analysis that this field-driven ionic motion across the whole area is sustained even if a filament is formed in the tunnel barrier and the device is transformed into a filamentary-type switching mode.
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Affiliation(s)
- Christoph Baeumer
- Peter Gruenberg Institute 7, Forschungszentrum Juelich GmbH, JARA-FIT, 52425 Juelich, Germany.
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11
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Heisig T, Baeumer C, Gries UN, Mueller MP, La Torre C, Luebben M, Raab N, Du H, Menzel S, Mueller DN, Jia CL, Mayer J, Waser R, Valov I, De Souza RA, Dittmann R. Oxygen Exchange Processes between Oxide Memristive Devices and Water Molecules. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1800957. [PMID: 29882270 DOI: 10.1002/adma.201800957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/18/2018] [Indexed: 06/08/2023]
Abstract
Resistive switching based on transition metal oxide memristive devices is suspected to be caused by the electric-field-driven motion and internal redistribution of oxygen vacancies. Deriving the detailed mechanistic picture of the switching process is complicated, however, by the frequently observed influence of the surrounding atmosphere. Specifically, the presence or absence of water vapor in the atmosphere has a strong impact on the switching properties, but the redox reactions between water and the active layer have yet to be clarified. To investigate the role of oxygen and water species during resistive switching in greater detail, isotope labeling experiments in a N2 /H218 O tracer gas atmosphere combined with time-of-flight secondary-ion mass spectrometry are used. It is explicitly demonstrated that during the RESET operation in resistive switching SrTiO3 -based memristive devices, oxygen is incorporated directly from water molecules or oxygen molecules into the active layer. In humid atmospheres, the reaction pathway via water molecules predominates. These findings clearly resolve the role of humidity as both oxidizing agent and source of protonic defects during the RESET operation.
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Affiliation(s)
- Thomas Heisig
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - Christoph Baeumer
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - Ute N Gries
- Institute of Physical Chemistry, RWTH Aachen University, 52056, Aachen, Germany
| | - Michael P Mueller
- Institute of Physical Chemistry, RWTH Aachen University, 52056, Aachen, Germany
| | - Camilla La Torre
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Michael Luebben
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Nicolas Raab
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - Hongchu Du
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Juelich GmbH and RWTH Aachen University, 52425, Juelich, Germany
| | - Stephan Menzel
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - David N Mueller
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - Chun-Lin Jia
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Juelich GmbH and RWTH Aachen University, 52425, Juelich, Germany
| | - Joachim Mayer
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Juelich GmbH and RWTH Aachen University, 52425, Juelich, Germany
| | - Rainer Waser
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Ilia Valov
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - Roger A De Souza
- Institute of Physical Chemistry, RWTH Aachen University, 52056, Aachen, Germany
| | - Regina Dittmann
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
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12
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Wei LJ, Yuan Y, Wang J, Tu HQ, Gao Y, You B, Du J. Bipolar resistive switching with negative differential resistance effect in a Cu/BaTiO 3/Ag device. Phys Chem Chem Phys 2018; 19:11864-11868. [PMID: 28435942 DOI: 10.1039/c7cp01461a] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate that a bipolar non-volatile resistive switching behaviour with negative differential resistance (NDR) effect is realized in a Cu/BaTiO3/Ag device, which was deposited on a Si substrate via magnetron sputtering equipment. We suggest that the bipolar resistive switching is dominated by the trapping/detrapping of electrons at the BaTiO3-Cu interface. In addition, we demonstrate that the device exhibits good performance, including a large on/off ratio, high reliability and long retention time. Therefore, BaTiO3 may become a good candidate for application in resistive switching random access memory (RRAM) devices.
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Affiliation(s)
- L J Wei
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
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13
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Yin XB, Yang R, Xue KH, Tan ZH, Zhang XD, Miao XS, Guo X. Mimicking the brain functions of learning, forgetting and explicit/implicit memories with SrTiO 3-based memristive devices. Phys Chem Chem Phys 2018; 18:31796-31802. [PMID: 27841389 DOI: 10.1039/c6cp06049h] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To implement the complex brain functions of learning, forgetting and memory in a single electronic device is very advantageous for realizing artificial intelligence. As a proof of concept, memristive devices with a simple structure of Ni/Nb-SrTiO3/Ti were investigated in this work. The functions of learning, forgetting and memory were successfully mimicked using the memristive devices, and the "time-saving" effect of implicit memory was also demonstrated. The physics behind the brain functions is simply the modulation of the Schottky barrier at the Ni/SrTiO3 interface. The realization of various psychological functions in a single device simplifies the construction of the artificial neural network and facilitates the advent of artificial intelligence.
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Affiliation(s)
- Xue-Bing Yin
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
| | - Rui Yang
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
| | - Kan-Hao Xue
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Zheng-Hua Tan
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
| | - Xiao-Dong Zhang
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
| | - Xiang-Shui Miao
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Xin Guo
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
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14
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Lee J, Lu WD. On-Demand Reconfiguration of Nanomaterials: When Electronics Meets Ionics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30. [PMID: 28985005 DOI: 10.1002/adma.201702770] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/01/2017] [Indexed: 05/04/2023]
Abstract
Rapid advances in the semiconductor industry, driven largely by device scaling, are now approaching fundamental physical limits and face severe power, performance, and cost constraints. Multifunctional materials and devices may lead to a paradigm shift toward new, intelligent, and efficient computing systems, and are being extensively studied. Herein examines how, by controlling the internal ion distribution in a solid-state film, a material's chemical composition and physical properties can be reversibly reconfigured using an applied electric field, at room temperature and after device fabrication. Reconfigurability is observed in a wide range of materials, including commonly used dielectric films, and has led to the development of new device concepts such as resistive random-access memory. Physical reconfigurability further allows memory and logic operations to be merged in the same device for efficient in-memory computing and neuromorphic computing systems. By directly changing the chemical composition of the material, coupled electrical, optical, and magnetic effects can also be obtained. A survey of recent fundamental material and device studies that reveal the dynamic ionic processes is included, along with discussions on systematic modeling efforts, device and material challenges, and future research directions.
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Affiliation(s)
- Jihang Lee
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Wei D Lu
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
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15
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Valence Change Bipolar Resistive Switching Accompanied With Magnetization Switching in CoFe 2O 4 Thin Film. Sci Rep 2017; 7:12427. [PMID: 28963521 PMCID: PMC5622061 DOI: 10.1038/s41598-017-12579-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 08/31/2017] [Indexed: 12/03/2022] Open
Abstract
Resistive Switching in oxides has offered new opportunities for developing resistive random access memory (ReRAM) devices. Here we demonstrated bipolar Resistive Switching along with magnetization switching of cobalt ferrite (CFO) thin film using Al/CFO/FTO sandwich structure, which makes it a potential candidate for developing future multifunctional memory devices. The device shows good retention characteristic time (>104 seconds) and endurance performance, a good resistance ratio of high resistance state (HRS) and low resistance state (LRS) ~103. Nearly constant resistance values in LRS and HRS confirm the stability and non-volatile nature of the device. The device shows different conduction mechanisms in the HRS and LRS i.e. Schottky, Poole Frenkel and Ohmic. Magnetization of the device is also modulated by applied electric field which has been attributed to the oxygen vacancies formed/annihilated during the voltage sweep and indicates the presence of valence change mechanism (VCM) in our device. It is suggested that push/pull of oxygen ions from oxygen diffusion layer during voltage sweep is responsible for forming/rupture of oxygen vacancies conducting channels, leading to switching between LRS and HRS and for switching in magnetization in CFO thin film. Presence of VCM in our device was confirmed by X-ray Photoelectron Spectroscopy at Al/CFO interface.
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16
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Wang X, Gao B, Wu H, Li X, Hong D, Chen Y, Qian H. A nondestructive approach to study resistive switching mechanism in metal oxide based on defect photoluminescence mapping. NANOSCALE 2017; 9:13449-13456. [PMID: 28657082 DOI: 10.1039/c7nr02023f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The mechanism of resistive switching in metal oxides is a widely studied topic with interest in both fundamental physics and the practical need to improve device characteristics for memory based applications. Various experimental approaches were employed to reveal the different aspects of resistive switching; however, there is still a debate on the switching mechanism due to the lack of nondestructive microscopic characterization tools to monitor the oxygen vacancies. In this study, a novel approach using photoluminescence (PL) mapping was developed to study switching dynamics in metal oxides. By monitoring the emission properties with a confocal PL system, information regarding the switching mechanism can be obtained. The nondestructive nature of this approach allowed us to make comparisons between different switching conditions and endurance cycles. SrTiO3 based switching devices were used in the study. The distribution of oxygen vacancies can be positioned by mapping the integrated intensity of oxygen vacancy emission on a transparent top electrode, and both interface switching and filament switching can be distinguished. Moreover, the endurance study revealed a sudden rise in the emission intensity correlated with the device failure, which indicates an abrupt increase in the localized density of oxygen vacancies that results in an irreversible set process for the conductive filament.
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Affiliation(s)
- Xiaohu Wang
- Institute of Microelectronics, Tsinghua University, Beijing, China.
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17
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Cooper D, Baeumer C, Bernier N, Marchewka A, La Torre C, Dunin-Borkowski RE, Menzel S, Waser R, Dittmann R. Anomalous Resistance Hysteresis in Oxide ReRAM: Oxygen Evolution and Reincorporation Revealed by In Situ TEM. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1700212. [PMID: 28417593 DOI: 10.1002/adma.201700212] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/14/2017] [Indexed: 06/07/2023]
Abstract
The control and rational design of redox-based memristive devices, which are highly attractive candidates for next-generation nonvolatile memory and logic applications, is complicated by competing and poorly understood switching mechanisms, which can result in two coexisting resistance hystereses that have opposite voltage polarity. These competing processes can be defined as regular and anomalous resistive switching. Despite significant characterization efforts, the complex nanoscale redox processes that drive anomalous resistive switching and their implications for current transport remain poorly understood. Here, lateral and vertical mapping of O vacancy concentrations is used during the operation of such devices in situ in an aberration corrected transmission electron microscope to explain the anomalous switching mechanism. It is found that an increase (decrease) in the overall O vacancy concentration within the device after positive (negative) biasing of the Schottky-type electrode is associated with the electrocatalytic release and reincorporation of oxygen at the electrode/oxide interface and is responsible for the resistance change. This fundamental insight presents a novel perspective on resistive switching processes and opens up new technological opportunities for the implementation of memristive devices, as anomalous switching can now be suppressed selectively or used deliberately to achieve the desirable so-called deep Reset.
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Affiliation(s)
- David Cooper
- Université Grenoble Alpes, F-38000, Grenoble, France
- CEA, LETI, Minatec Campus, F-38054, Grenoble, France
| | - Christoph Baeumer
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - Nicolas Bernier
- Université Grenoble Alpes, F-38000, Grenoble, France
- CEA, LETI, Minatec Campus, F-38054, Grenoble, France
| | - Astrid Marchewka
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Camilla La Torre
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Rafal E Dunin-Borkowski
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Juelich GmbH and RWTH Aachen University, 52425, Juelich, Germany
| | - Stephan Menzel
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - Rainer Waser
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Regina Dittmann
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
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18
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Tan ZH, Yin XB, Yang R, Mi SB, Jia CL, Guo X. Pavlovian conditioning demonstrated with neuromorphic memristive devices. Sci Rep 2017; 7:713. [PMID: 28386075 PMCID: PMC5429711 DOI: 10.1038/s41598-017-00849-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 03/16/2017] [Indexed: 12/02/2022] Open
Abstract
Pavlovian conditioning, a classical case of associative learning in a biological brain, is demonstrated using the Ni/Nb-SrTiO3/Ti memristive device with intrinsic forgetting properties in the framework of the asymmetric spike-timing-dependent plasticity of synapses. Three basic features of the Pavlovian conditioning, namely, acquisition, extinction and recovery, are implemented in detail. The effects of the temporal relation between conditioned and unconditioned stimuli as well as the time interval between individual training trials on the Pavlovian conditioning are investigated. The resulting change of the response strength, the number of training trials necessary for acquisition and the number of extinction trials are illustrated. This work clearly demonstrates the hardware implementation of the brain function of the associative learning.
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Affiliation(s)
- Zheng-Hua Tan
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Xue-Bing Yin
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China
| | - Rui Yang
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China.
| | - Shao-Bo Mi
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P.R. China
| | - Chun-Lin Jia
- School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, 710049, P.R. China.,Peter Grünberg Institute and Ernst Ruska Center for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Xin Guo
- Laboratory of Solid State Ionics, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P.R. China.
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19
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Wrana D, Rodenbücher C, Krawiec M, Jany BR, Rysz J, Ermrich M, Szot K, Krok F. Tuning the surface structure and conductivity of niobium-doped rutile TiO2 single crystals via thermal reduction. Phys Chem Chem Phys 2017; 19:30339-30350. [DOI: 10.1039/c7cp03136j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on the systematic exploration of electronic and structural changes of Nb-doped rutile TiO2(110) single crystal surfaces due to the thermoreduction under ultra-high vacuum conditions (without sputtering), with comparison to undoped TiO2(110) crystals.
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Affiliation(s)
- D. Wrana
- Marian Smoluchowski Institute of Physics
- Jagiellonian University
- 30-348 Krakow
- Poland
| | - C. Rodenbücher
- Peter Grünberg Institute and JARA-FIT
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - M. Krawiec
- Institute of Physics
- Maria Curie-Sklodowska University
- 20-031 Lublin
- Poland
| | - B. R. Jany
- Marian Smoluchowski Institute of Physics
- Jagiellonian University
- 30-348 Krakow
- Poland
| | - J. Rysz
- Marian Smoluchowski Institute of Physics
- Jagiellonian University
- 30-348 Krakow
- Poland
| | - M. Ermrich
- Röntgenlabor Dr. Ermrich
- D – 64354 Reinheim
- Germany
| | - K. Szot
- Peter Grünberg Institute and JARA-FIT
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
- A. Chełkowski Institute of Physics
| | - F. Krok
- Marian Smoluchowski Institute of Physics
- Jagiellonian University
- 30-348 Krakow
- Poland
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