scholarly journals Ferroelectric 2D ice under graphene confinement

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hao-Ting Chin ◽  
Jiri Klimes ◽  
I-Fan Hu ◽  
Ding-Rui Chen ◽  
Hai-Thai Nguyen ◽  
...  

AbstractWe here report on the direct observation of ferroelectric properties of water ice in its 2D phase. Upon nanoelectromechanical confinement between two graphene layers, water forms a 2D ice phase at room temperature that exhibits a strong and permanent dipole which depends on the previously applied field, representing clear evidence for ferroelectric ordering. Characterization of this permanent polarization with respect to varying water partial pressure and temperature reveals the importance of forming a monolayer of 2D ice for ferroelectric ordering which agrees with ab-initio and molecular dynamics simulations conducted. The observed robust ferroelectric properties of 2D ice enable novel nanoelectromechanical devices that exhibit memristive properties. A unique bipolar mechanical switching behavior is observed where previous charging history controls the transition voltage between low-resistance and high-resistance state. This advance enables the realization of rugged, non-volatile, mechanical memory exhibiting switching ratios of 106, 4 bit storage capabilities and no degradation after 10,000 switching cycles.

2020 ◽  
Vol 20 (5) ◽  
pp. 3283-3286 ◽  
Author(s):  
Yuehua An ◽  
Xia Shen ◽  
Yuying Hao ◽  
Pengfei Guo ◽  
Weihua Tang

Conductive filament mechanism can explain major resistance switching behaviors. The forming/deforming of the filaments define the high/low resistance states. The ratio of high/low resistance depends on the characterization of the filaments. In many oxide systems, the oxygen vacancies are important to forming the conductive filaments for the resistance switching behaviors. As ultrawide band gap semiconductor, Ga2O3 has very high resistance for its high resistance state, while its low resistive state has relative high resistance, which normally results in low ratio of high/low resistance. In this letter, we report a high ratio of high/low resistance by ultraviolet radiation. The I–V characteristics of Au/Ti/β-Ga2O3/W sandwich structure device shows that the HRS to LRS ratio of 5 orders is achieved.


2011 ◽  
Vol 687 ◽  
pp. 106-111
Author(s):  
Chih Yi Liu ◽  
Yu Chen Li ◽  
Chun Hung Lai ◽  
Shih Kun Liu

CuxO and SiO2thin films were deposited using a radio-frequency magnetron sputter on Pt/Ti/SiO2/Si substrates to form SiO2/CuxO/Pt and CuxO/Pt structures. The current-voltage characteristics were measured by DC voltage sweeping using a tungsten (W) probe. The two structures needed a large voltage to initiate the first resistive switching; this sweep was called the forming process. Afterwards, the resistances of the two structures could be switched reversibly between the low-resistance-state (LRS) and high-resistance-state (HRS) by applying a DC voltage. The conduction mechanisms of the LRS and the HRS were dominated by Ohmic conduction. Structures with non-destructive readout characteristics and long retention time were suitable for use in non-volatile memory. The difference between resistive switching in W-probe/SiO2/CuxO/Pt and W-probe/CuxO/Pt structures was investigated. The additional SiO2layer decreased the switching voltages and currents; this should be due to the presence of pinholes within the SiO2layer. The influence of SiO2thickness on the resistive switching characteristics was also investigated. The switching voltages and currents, except the forming voltage, decreased as the thickness of SiO2decreased. The conducting filament model with a thermochemical reaction was suggested to best explain the resistive switching behavior that was observed.


Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 318
Author(s):  
Lin ◽  
Wu ◽  
Chen

: In this work, the resistive switching characteristics of resistive random access memories (RRAMs) containing Sm2O3 and V2O5 films were investigated. All the RRAM structures made in this work showed stable resistive switching behavior. The High-Resistance State and Low-Resistance State of Resistive memory (RHRS/RLRS) ratio of the RRAM device containing a V2O5/Sm2O3 bilayer is one order of magnitude higher than that of the devices containing a single layer of V2O5 or Sm2O3. We also found that the stacking sequence of the Sm2O3 and V2O5 films in the bilayer structure can affect the switching features of the RRAM, causing them to exhibit both bipolar resistive switching (BRS) behavior and self-compliance behavior. The current conduction mechanisms of RRAM devices with different film structures were also discussed.


2021 ◽  
Vol 2065 (1) ◽  
pp. 012001
Author(s):  
Z J Weng ◽  
Z W Zhao ◽  
H L Jiang ◽  
Y Fang

Abstract The continued exploration of novel synthetic memristive materials with multifunctional properties is critical for future synapse-emulating circuits and electronic devices in the field of next-generation neuromorphic computing applications. In this work, the silver nanowires (AgNWs)-Egg albumen composites have been integrated as a resistive switching layer in the Ag/AgNWs-Egg albumen/Ag planar structure and exhibits both unipolar (memory) switching and threshold switching functions. The device in unipolar switching regime demonstrates an ON/OFF ratio above 105, a low resistance state of about 1.2 KΩ and a high resistance state of about 120 MΩ. Finally, a mechanism in combination with the conductive filament theory and a tunnelling conduction mechanism is proposed to explain the resistive switching behavior. The devices are prepared by simple and low-cost techniques, which make such devices appealing for future electronic applications.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Chih-Yi Liu ◽  
Yueh-Ying Tsai ◽  
Wen-Tsung Fang ◽  
Hung-Yu Wang

A 20 nm SiOxlayer is deposited using radio-frequency sputtering to form the resistive switching layer of a Cu/SiOx/Pt memory device. The SiOx-based device demonstrates the resistive switching characteristics with an electrochemical reaction. CF4plasma treatment was used to modify the SiOxlayer and incorporate fluorine atoms into theSiOxlayer. The bombardment damage and fluorine incorporation caused the SiOxfilm to form a stack-like structure. This reduced the operating voltage and improved switching dispersion. The fluorine repaired the Cu/SiOxinterface, thus increasing the barrier height of the Cu/SiOxinterface and the resistance of the high resistance state. A statistical analysis of the conducting filament formation was performed in order to evaluate the number of formation/rupture sites. The resistive switching of the CF4-treated sample had higher possibility to use the same filament sites; thus, the CF4-treated sample had stable resistive switching behavior.


1999 ◽  
Vol 600 ◽  
Author(s):  
Anil R. Duggal

AbstractThe high power electrical switching properties of a polymer current limiter device are studied as a function of applied voltage. It is shown that a dramatic change in switching behavior occurs at a characteristic voltage. Below this voltage, the device switches to a high resistance state whereas at higher applied voltages it does not. It is shown that the high voltage, low resistance state has similar electrical characteristics to an arc discharge. Material variation experiments are also described which demonstrate that the changeover depends sensitively on the contact resistance between the filler particles of the composite material.


2019 ◽  
Vol 54 (5) ◽  
pp. 703-710 ◽  
Author(s):  
Liliana S Melro ◽  
Lars R Jensen

The interface of graphene/epoxy was studied using molecular dynamics simulations by calculating the work of separation and traction-separation responses in the normal mode. The influence of functionalization of the graphene layers on the traction-separation behaviour was also examined by grafting hydroxyl, carboxyl, and carbonyl groups. It is shown that the magnitude of the maximum traction is clearly larger for functionalized graphene/epoxy systems as compared to pristine graphene. The work of adhesion also shows a clear difference in the interface behaviour of functionalized graphene/epoxy and pristine/epoxy systems with the presence of functional groups generating higher values of work of separation.


2012 ◽  
Vol 1430 ◽  
Author(s):  
Xiaoli He ◽  
Robert E. Geer

ABSTRACTThe resistive switching properties of CMOS compatible TiN/HfO2/TiN resistive-random-access-memory (ReRAM) devices have been investigated after exposure to 1 MeV proton radiation. The HfO2-based ReRAM devices were found to have high total-ionizing-dose (TID) radiation tolerance up to 5 Grad(Si). TiN/HfO2/TiN ReRAM performance parameters include high-resistance state (HRS) resistance, low-resistance state (LRS) resistance, set and reset voltages. HfO2-based ReRAM devices exhibited no degradation in these performance parameters following proton irradiation exposure with TID from 105 to 109 rad(Si). Furthermore, the HfO2-based ReRAM devices exhibited more uniform resistive switching behavior with increased TID. Based on this radiation response it is proposed that the resistive switching mechanism in TiN/HfO2/TiN – trap-assisted tunneling associated with Hf-rich conducting filament formation – may be reinforced through proton exposure which acts to stabilize the formation/rupture of Hf-rich filaments. The high radiation tolerance of HfO2-based ReRAM devices suggests such devices may be potentially attractive for aerospace and nuclear applications.


2017 ◽  
Vol 30 (4) ◽  
pp. 65-68
Author(s):  
Eric Hernandez Rodriguez ◽  
Alfredo Marquez Herrera ◽  
Miguel Melendez Lira ◽  
Enrique Valaguez Velazquez ◽  
Martin Zapata Torres

We investigated the electric-field-induced resistance-switching behavior of metal-insulator-metal (MIM) cells based on TiO2 thin films fabricated by the reactive RF-sputtering technique. MIM cells were constructed by sandwiched TiO2 thin films between a pair of electrodes; Ti thin films were employed to form an ohmic bottom contact and NiCr thin films were employed to form Schottky top electrodes obtaining Ti/TiO2/NiCr MIM cells. Schottky barrier height for the TiO2/NiCr junction was determined according to the thermionic emission model by using the Cheung´s functions. SEM and Raman analysis of the TiO2 thin films were carried out to ensure the quality of the films. Current-Voltage (I-V) sweeps obtained at room temperature by the application of dc bias showed a bipolar resistive switching behavior on the cells. Both low resistance state (ON state) and high resistance state (OFF state), of Ti/TiO2/NiCr cells are stable and reproducible during a successive resistive switching. The resistance ratio of ON and OFF state is over 103 and the retention properties of both states are very stable after 105 s with a voltage test of 0.1 V.


2015 ◽  
Vol 764-765 ◽  
pp. 87-91
Author(s):  
Fu Chien Chiu

In this work, metal/oxide/metal capacitors were fabricated and investigated using transparent boron-doped zinc oxide (ZnO:B) films for nonvolatile memory applications. Both top and bottom electrodes are tungsten. The average value of transmittance of ZnO:B films grown on silicon substrates is found to be about 91% in the visible light region. According to the relationship between transmittance and wavelength, the optical band gap of ZnO:B films is determined to be about 3.26 eV. The temperature dependent current-voltage curves show that the current density increases with increasing temperature in low-resistance state (LRS), meanwhile, the current density decreases with increasing temperature in high-resistance state (HRS). From the resistive switching behavior of the W/ZnO:B/W memory devices, the reset voltage which triggers the memory devices from an LRS to an HRS is independent of temperature. On the other hand, the set voltage which triggers the memory devices from an HRS to an LRS is increased with temperature.


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