Functional Gradient Transparent Conducting Oxide Nanowire Arrays as Monophasic Schottky-Barrier Free Memristors for Bipolar Linear Switching

2020 ◽  
Author(s):  
Thomas Herzog ◽  
Naomi Weitzel ◽  
Sebastian Polarz
Keyword(s):  
Schottky Barrier ◽  
Data Storage ◽  
Tin Oxide ◽  
Transparent Conducting Oxide ◽  
Electrical Potential ◽  
High Resistance State ◽  
Nanowire Arrays ◽  
Metal Metal ◽  
Resistance State ◽  
Barrier Free

<div><div><div><p>One of the fascinating properties of metal-semiconductor Schottky-barriers, which has been observed for some material combinations, is memristive behavior. Memristors are smart, since they can reversibly switch between a low resistance state and a high resistance state. The devices offer a great potential for advanced computing and data storage, including neuromorphic networks and resistive random-access memory. However, as for many other cases, the presence of a real interface (metal - metal oxide) has numerous disadvantages. The realization of interface-free, respectively Schottky-barrier free memristors is highly desirable. The aim of the current paper is the generation of nanowire arrays with each nanorod possessing the same crystal phase (Rutile) and segments only differing in composition. The electric conductivity is realized by segments made of highly-doped antimony tin oxide (ATO) transitioning into pure tin oxide (TO). Complex nanoarchitectures are presented, which include ATO-TO, ATO-TO-ATO nanowires either with a stepwise distribution of antimony or as a graded functional material. The electrical characterization of the materials reveals that the introduction of memristive properties in such structures is possible. The special features observed in voltage-current (IV) curves are correlated to the behavior of mobile oxygen vacancies (VO..) at different values of applied electrical potential.</p></div></div></div>

Functional Gradient Transparent Conducting Oxide Nanowire Arrays as Monophasic Schottky-Barrier Free Memristors for Bipolar Linear Switching

2020 ◽  
Author(s):  
Thomas Herzog ◽  
Naomi Weitzel ◽  
Sebastian Polarz
Keyword(s):  
Schottky Barrier ◽  
Data Storage ◽  
Tin Oxide ◽  
Transparent Conducting Oxide ◽  
Electrical Potential ◽  
High Resistance State ◽  
Nanowire Arrays ◽  
Metal Metal ◽  
Resistance State ◽  
Barrier Free

<div><div><div><p>One of the fascinating properties of metal-semiconductor Schottky-barriers, which has been observed for some material combinations, is memristive behavior. Memristors are smart, since they can reversibly switch between a low resistance state and a high resistance state. The devices offer a great potential for advanced computing and data storage, including neuromorphic networks and resistive random-access memory. However, as for many other cases, the presence of a real interface (metal - metal oxide) has numerous disadvantages. The realization of interface-free, respectively Schottky-barrier free memristors is highly desirable. The aim of the current paper is the generation of nanowire arrays with each nanorod possessing the same crystal phase (Rutile) and segments only differing in composition. The electric conductivity is realized by segments made of highly-doped antimony tin oxide (ATO) transitioning into pure tin oxide (TO). Complex nanoarchitectures are presented, which include ATO-TO, ATO-TO-ATO nanowires either with a stepwise distribution of antimony or as a graded functional material. The electrical characterization of the materials reveals that the introduction of memristive properties in such structures is possible. The special features observed in voltage-current (IV) curves are correlated to the behavior of mobile oxygen vacancies (VO..) at different values of applied electrical potential.</p></div></div></div>

Analysis on Resistance Change Mechanism of NiO-ReRAM Using Visualization Technique of Data Storage Area With Secondary Electron Image

2010 ◽  
Vol 1250 ◽  
Author(s):  
Kentaro Kinoshita ◽  
Tatsuya Makino ◽  
Yoda Takatoshi ◽  
Dobashi Kazufumi ◽  
Kishida Satoru
Keyword(s):  
Data Storage ◽  
Secondary Electron ◽  
High Resistance State ◽  
Secondary Electron Image ◽  
Resistance Change ◽  
Force Microscopy ◽  
Electron Image ◽  
Storage Area ◽  
Resistance State ◽  
Pt Films

AbstractBoth a low resistance state and a high resistance state which were written by the voltage application in a local region of NiO/Pt films by using conducting atomic force microscopy (C-AFM) were observed by using scanning electron microscope (SEM) and electron probe micro analysis (EPMA). The writing regions are distinguishable as dark areas in a secondary electron image and thus can be specified without using complicated sample fabrication process to narrow down the writing regions such as the photolithography technique. In addition, the writing regions were analyzed by using energy dispersive X-ray spectroscopy (EDS) mapping. No difference between the inside and outside of the writing regions is observed for all the mapped elements including C and Rh. Here, C and Rh are the most probable candidates for contamination which affect the secondary electron image. Therefore, our results suggested that the observed change in the contrast of the second electron image is related to the intrinsic change in the electronic state of the NiO film and a secondary electron yield is correlated to the physical properties of the film.

scholarly journals Flexible Memory Device Composed of Metal-Oxide and Two-Dimensional Material (SnO2/WTe2) Exhibiting Stable Resistive Switching

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7535
Author(s):  
Ghulam Dastgeer ◽  
Amir Muhammad Afzal ◽  
Jamal Aziz ◽  
Sajjad Hussain ◽  
Syed Hassan Abbas Jaffery ◽  
...  
Keyword(s):  
Data Storage ◽  
Resistive Switching ◽  
High Resistance State ◽  
Building Blocks ◽  
Memory Device ◽  
Memory Storage ◽  
Memory Devices ◽  
Two Dimensional ◽  
Ag Filament ◽  
Resistance State

Two-terminal, non-volatile memory devices are the fundamental building blocks of memory-storage devices to store the required information, but their lack of flexibility limits their potential for biological applications. After the discovery of two-dimensional (2D) materials, flexible memory devices are easy to build, because of their flexible nature. Here, we report on our flexible resistive-switching devices, composed of a bilayer tin-oxide/tungsten-ditelluride (SnO2/WTe2) heterostructure sandwiched between Ag (top) and Au (bottom) metal electrodes over a flexible PET substrate. The Ag/SnO2/WTe2/Au flexible devices exhibited highly stable resistive switching along with an excellent retention time. Triggering the device from a high-resistance state (HRS) to a low-resistance state (LRS) is attributed to Ag filament formation because of its diffusion. The conductive filament begins its development from the anode to the cathode, contrary to the formal electrochemical metallization theory. The bilayer structure of SnO2/WTe2 improved the endurance of the devices and reduced the switching voltage by up to 0.2 V compared to the single SnO2 stacked devices. These flexible and low-power-consumption features may lead to the construction of a wearable memory device for data-storage purposes.

scholarly journals Gradually Modified Conductance in the Self-Compliance Region of an Atomic-Layer-Deposited Pt/TiO2/HfAlOx/TiN RRAM Device

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1199
Author(s):  
Hojeong Ryu ◽  
Sungjun Kim
Keyword(s):  
Photoelectron Spectroscopy ◽  
Depth Profiling ◽  
Atomic Layer ◽  
High Resistance State ◽  
Long Term Potentiation ◽  
Memory Device ◽  
Bipolar Resistive Switching ◽  
Term Potentiation ◽  
Resistance State ◽  
Neuromorphic System

This study presents conductance modulation in a Pt/TiO2/HfAlOx/TiN resistive memory device in the compliance region for neuromorphic system applications. First, the chemical and material characteristics of the atomic-layer-deposited films were verified by X-ray photoelectron spectroscopy depth profiling. The low-resistance state was effectively controlled by the compliance current, and the high-resistance state was adjusted by the reset stop voltage. Stable endurance and retention in bipolar resistive switching were achieved. When a compliance current of 1 mA was imposed, only gradual switching was observed in the reset process. Self-compliance was used after an abrupt set transition to achieve a gradual set process. Finally, 10 cycles of long-term potentiation and depression were obtained in the compliance current region for neuromorphic system applications.

Resistive Switching Characteristics in TiO2 ReRAM with Top Electrode of Co Selectively Formed on SAMs Printed Patterns

2007 ◽  
Vol 124-126 ◽  
pp. 603-606
Author(s):  
Sang Hee Won ◽  
Seung Hee Go ◽  
Jae Gab Lee
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
Atomic Layer ◽  
High Resistance State ◽  
Resistive Random Access Memory ◽  
Tio2 Thin Films ◽  
Selective Deposition ◽  
Precise Control ◽  
Resistance State ◽  
Switching Characteristics

Simple process for the fabrication of Co/TiO2/Pt resistive random access memory, called ReRAM, has been developed by selective deposition of Co on micro-contact printed (μ-CP) self assembled monolayers (SAMs) patterns. Atomic Layer Deposition (ALD) was used to deposit TiO2 thin films, showing its ability of precise control over the thickness of TiO2, which is crucial to obtain proper resistive switching properties of TiO2 ReRAM. The fabrication process for Co/TiO2/Pt ReRAM involves the ALD of TiO2 on sputter-deposited Pt bottom electrode, followed by μ-CP with SAMs and then selective deposition of Co. This results in the Co/TiO2/Pt structure ReRAM. For comparison, Pt/TiO2/Pt ReRAM was produced and revealing the similar switching characteristics as that of Co/TiO2/Pt, thus indicating the feasibility of Co replacement with Pt top electrode. The ratios between the high-resistance state (Off state) and the low-resistance state (On state) were larger than 102. Consequently, the selective deposition of Co with μ-CP, newly developed in this study, can simplify the process and thus implemented into the fabrication of ReRAM.

Molecule‐Upgraded van der Waals Contacts for Schottky‐Barrier‐Free Electronics

2021 ◽  
pp. 2104935
Author(s):  
Xiankun Zhang ◽  
Zhuo Kang ◽  
Li Gao ◽  
Baishan Liu ◽  
Huihui Yu ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Van Der Waals ◽  
Van Der Waals Contacts ◽  
Barrier Free

scholarly journals Optimization Preparation of Indium Tin Oxide Nanoparticles via Microemulsion Method Using Orthogonal Experiment

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1387
Author(s):  
Zhucheng Jiang ◽  
Ting Liu ◽  
Xiaoyu Zhai ◽  
Jiaxiang Liu
Keyword(s):  
Calcination Temperature ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Orthogonal Experiment ◽  
Transparent Conducting Oxide ◽  
Molar Ratio ◽  
Experimental Conditions ◽  
Microemulsion Method ◽  
Low Resistivity ◽  
Ito Nanoparticles

Indium tin oxide (ITO), an experimentally friendly transparent conducting oxide (TCO), has attracted great attention in the photoelectric field due to its intrinsically low resistivity and high transparency. In this work, the experimental conditions of preparing ITO nanoparticles using the microemulsion method were optimized by an orthogonal experiment. The optimal experimental conditions were obtained: mass ratio of the surfactant (AEO-3, MOA-5), a co-surfactant (n-propyl alcohol) of 5:3, molar ratio of indium and ammonia of 1:20, calcination temperature of 700 °C and calcination time of 4 h. Subsequently, the influence from process variables on the resistivity was researched systematically. The results demonstrated that the calcination temperature had a great effect on the resistivity; the resistivity reduced from 11.28 to 2.72 Ω·cm with the increase in the calcination temperature from 500 to 700 °C. Ultimately, ITO nanoparticles were prepared and systematically characterized under the optimal experimental conditions. The particles with a size of 60 nm were attributed to the cubic ITO crystal phase and showed low resistivity of 0.3675 Ω·cm. Significantly, ITO nanoparticles with low resistivity were obtained using the microemulsion method, which has potential application in the field of ITO nanoparticle preparation.

scholarly journals Effect Of Fluorine Doping On The Structural, Optical And Electrical Properties Of Spin Coated Tin Oxide Thin Films For Solar Cells Application

2019 ◽  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Electrical Properties ◽  
Tin Oxide ◽  
Transparent Conducting Oxide ◽  
Optical And Electrical Properties ◽  
Fluorine Doping ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transparent Conducting

Transparent conducting oxide (TCO) thin films are materials of significance for their applications in optoelectronics and sun powered cells. Fluorine-doped tin oxide (FTO) is an elective material in the advancement of TCO films. This paper reports the impact of fluorine doping on structural, optical and electrical properties of tin oxide thin films for solar cells application. The sol-gel was prepared from anhydrous stannous chloride, SnCl2 as an originator, 2-methoxyethanol as a solvent, di-ethanolamine as a preservative and ammonium fluoride as the dopant source. FTO precursor solution was formulated to obtain 0, 5, 10, 15 and 20 % doping concentration and deposited on glass substrates by means of spin coater at the rate of 2000 rpm for 40 seconds. After pre-heated at 200 oC, the samples were annealed at 600 oC for 2 h. The structural, optical and electrical characteristics of prepared films were characterized using X-ray diffraction (XRD) analysis, UV-visible spectroscopy and electrical measurement. X-ray diffraction (XRD) investigation of the films demonstrated that the films were polycrystalline in nature with tetragonal-cassiterite structure with most extraordinary pinnacle having a grain size of 17.01 nm. Doping with fluorine decreases the crystallite size. There was increment in the absorbance of the film with increasing wavelength and the transmittance was basically reduced with increasing fluorine doping in the visible region. The energy band gaps were in the range of 4.106-4.121 eV. The sheet resistance were observed to decrease as the doping percentage of fluorine increased with exception at higher doping of 15 and 20 %. In view of these outcomes, FTO thin films prepared could have useful application in transparent conducting oxide electrode in solar cell.

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