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Paul F, Paul S. To Be or Not to Be - Review of Electrical Bistability Mechanisms in Polymer Memory Devices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2106442. [PMID: 35132772 DOI: 10.1002/smll.202106442] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 12/24/2021] [Indexed: 06/14/2023]
Abstract
Organic memory devices are a rapidly evolving field with much improvement in device performance, fabrication, and application. But the reports have been disparate in terms of the material behavior and the switching mechanisms in the devices. And, despite the advantages, the lack of agreement in regards to the switching behavior of the memory devices is the biggest challenge that the field must overcome to mature as a commercial competitor. This lack of consensus has been the motivation of this work wherein various works are compiled together to understand influencing factors in the memory devices. Different works are compared together to discover some clues about the nature of the switching occurring in the devices, along with some missing links that would require further investigation. The charge storage mechanism is critically analyzed alongside the various resistive switching mechanisms such as filamentary conduction, redox-based switching, metal oxide switching, and other proposed mechanisms. The factors that affect the switching process are also analyzed including the effect of nanoparticles, the effect of the choice of polymer, or even the effect of electrodes on the switching behavior and the performance parameters of the memory device.
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Affiliation(s)
- Febin Paul
- Emerging Technologies Research Centre, De Montfort University, The Gateway, Leicester, LE1 9BH, UK
| | - Shashi Paul
- Emerging Technologies Research Centre, De Montfort University, The Gateway, Leicester, LE1 9BH, UK
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2
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Zarraoa L, González MU, Paulo ÁS. Imaging low-dimensional nanostructures by very low voltage scanning electron microscopy: ultra-shallow topography and depth-tunable material contrast. Sci Rep 2019; 9:16263. [PMID: 31700038 PMCID: PMC6838169 DOI: 10.1038/s41598-019-52690-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 10/18/2019] [Indexed: 11/08/2022] Open
Abstract
We demonstrate the implications of very low voltage operation (<1 kV) of a scanning electron microscope for imaging low-dimensional nanostructures where standard voltages (2-5 kV) involve a beam penetration depth comparable to the cross-section of the nanostructures. In this common situation, image sharpness, contrast quality and resolution are severely limited by emission of secondary electrons far from the primary beam incidence point. Oppositely, very low voltage operation allows reducing the beam-specimen interaction to an extremely narrow and shallow region around the incidence point, enabling high-resolution and ultra-shallow topographic contrast imaging by high-angle backscattered electrons detection on the one hand, and depth-tunable material contrast imaging by low-angle backscattered electrons detection on the other. We describe the performance of these imaging approaches on silicon nanowires obtained by the vapor-liquid-solid mechanism. Our experimental results, supported by Monte Carlo simulations of backscattered electrons emission from the nanowires, reveal the self-assembly of gold-silica core-shell nanostructures at the nanowire tips without any ad-hoc thermal oxidation step. This result demonstrates the capacity of very low voltage operation to provide optimum sharpness, contrast and resolution in low-dimensional nanostructures and to gather information about nanoscaled core-shell conformations otherwise impossible to obtain by standard scanning electron microscopy alone.
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Affiliation(s)
- Laura Zarraoa
- Instituto de Micro y Nanotecnología (IMN-CNM, CSIC), Isaac Newton 8, Tres Cantos, Spain
| | - María U González
- Instituto de Micro y Nanotecnología (IMN-CNM, CSIC), Isaac Newton 8, Tres Cantos, Spain
| | - Álvaro San Paulo
- Instituto de Micro y Nanotecnología (IMN-CNM, CSIC), Isaac Newton 8, Tres Cantos, Spain.
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Méndez M, Vega V, González S, Caballero-Flores R, García J, Prida VM. Effect of Sharp Diameter Geometrical Modulation on the Magnetization Reversal of Bi-Segmented FeNi Nanowires. NANOMATERIALS 2018; 8:nano8080595. [PMID: 30081591 PMCID: PMC6116228 DOI: 10.3390/nano8080595] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 01/17/2023]
Abstract
Controlling functional properties of matter and combining them for engineering a functional device is, nowadays, a common direction of the scientific community. For instance, heterogeneous magnetic nanostructures can make use of different types of geometrical and compositional modulations to achieve the control of the magnetization reversal along with the nano-entities and, thus, enable the fabrication of spintronic, magnetic data storage, and sensing devices, among others. In this work, diameter-modulated FeNi nanowires are fabricated paying special effort to obtain sharp transition regions between two segments of different diameters (from about 450 nm to 120 nm), enabling precise control over the magnetic behavior of the sample. Micromagnetic simulations performed on single bi-segmented nanowires predict a double step magnetization reversal where the wide segment magnetization switches near 16 kA/m through a vortex domain wall, while at 40 kA/m the magnetization of the narrow segment is reversed through a corkscrew-like mechanism. Finally, these results are confirmed with magneto-optic Kerr effect measurements at the transition of isolated bi-segmented nanowires. Furthermore, macroscopic vibrating sample magnetometry is used to demonstrate that the magnetic decoupling of nanowire segments is the main phenomenon occurring over the entire fabricated nanowires.
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Affiliation(s)
- Miguel Méndez
- Departamento de Física, Universidad de Oviedo, C/Federico Garcia Lorca 18, 33007-Oviedo, Asturias, Spain.
| | - Víctor Vega
- Laboratorio Membranas Nanoporosas, Servicios Científico-Técnicos, Universidad de Oviedo, Campus El Cristo s/n, 33006-Oviedo, Asturias, Spain.
| | - Silvia González
- Departamento de Física, Universidad de Oviedo, C/Federico Garcia Lorca 18, 33007-Oviedo, Asturias, Spain.
| | - Rafael Caballero-Flores
- Departamento de Física, Universidad de Oviedo, C/Federico Garcia Lorca 18, 33007-Oviedo, Asturias, Spain.
| | - Javier García
- Departamento de Física, Universidad de Oviedo, C/Federico Garcia Lorca 18, 33007-Oviedo, Asturias, Spain.
| | - Víctor M Prida
- Departamento de Física, Universidad de Oviedo, C/Federico Garcia Lorca 18, 33007-Oviedo, Asturias, Spain.
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Hartmann F, Maier P, Rebello Sousa Dias M, Göpfert S, Castelano LK, Emmerling M, Schneider C, Höfling S, Kamp M, Pershin YV, Marques GE, Lopez-Richard V, Worschech L. Nanoscale Tipping Bucket Effect in a Quantum Dot Transistor-Based Counter. NANO LETTERS 2017; 17:2273-2279. [PMID: 28296417 DOI: 10.1021/acs.nanolett.6b04911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electronic circuits composed of one or more elements with inherent memory, that is, memristors, memcapacitors, and meminductors, offer lower circuit complexity and enhanced functionality for certain computational tasks. Networks of these elements are proposed for novel computational paradigms that rely on information processing and storage on the same physical platform. We show a nanoscaled memdevice able to act as an electronic analogue of tipping buckets that allows reducing the dimensionality and complexity of a sensing problem by transforming it into a counting problem. The device offers a well adjustable, tunable, and reliable periodic reset that is controlled by the amounts of transferred quantum dot charges per gate voltage sweep. When subjected to periodic voltage sweeps, the quantum dot (bucket) may require up to several sweeps before a rapid full discharge occurs thus displaying period doubling, period tripling, and so on between self-governing reset operations.
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Affiliation(s)
- F Hartmann
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - P Maier
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - M Rebello Sousa Dias
- Departamento de Física, Universidade Federal de São Carlos , 13565-905, São Carlos, São Paulo, Brazil
- Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742, United States
| | - S Göpfert
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - L K Castelano
- Departamento de Física, Universidade Federal de São Carlos , 13565-905, São Carlos, São Paulo, Brazil
| | - M Emmerling
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - C Schneider
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - S Höfling
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
- SUPA, School of Physics and Astronomy, University of St. Andrews , St. Andrews, KY16 9SS, United Kingdom
| | - M Kamp
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
| | - Y V Pershin
- Department of Physics and Astronomy, University of South Carolina , Columbia, South Carolina 29208, United States
| | - G E Marques
- Departamento de Física, Universidade Federal de São Carlos , 13565-905, São Carlos, São Paulo, Brazil
| | - V Lopez-Richard
- Departamento de Física, Universidade Federal de São Carlos , 13565-905, São Carlos, São Paulo, Brazil
| | - L Worschech
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg , Am Hubland, D-97074 Würzburg, Germany
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