Memristors With Controllable Data Volatility by Loading Metal Ion-Added Ionic Liquids

Abstract

We demonstrate a new memristive device (IL-Memristor), in which an ionic liquid (IL) serve as a material to control the volatility of the resistance. ILs are ultra-low vapor pressure liquids consisting of cations and anions at room temperature, and their introduction into solid-state processes can provide new avenues in electronic device fabrication. Because the device resistance change in IL-Memristor is governed by a Cu filament formation/rupture in IL, we considered that the Cu filament stability affects the data retention characteristics. Therefore, we controlled the data retention time by clarifying the corrosion mechanism and performing the IL material design based on the results. It was found out that the corrosion of Cu filaments in the IL was ruled by the comproportionation reaction, and that the data retention characteristics of the devices varied depending on the valence of Cu ions added to the IL. Actually, IL-Memristors involving Cu(II) and Cu(I) show volatile and non-volatile nature with respect to the programmed resistance value, respectively. Our results showed that data volatility can be controlled through the metal ion species added to the IL. The present work indicates that IL-memristor is suitable for unique applications such as artificial neuron with tunable fading characteristics that is applicable to phenomena with a wide range of timescale.

Experimental Demonstration of In‐Memory Computing in a Ferrofluid System

“…Few former literature reports on liquid state memristors exist, most of which are liquid because of the use of liquid InGa alloy as electrodes [ 24 ] or ionic liquid as a medium, in which metallic conductive filaments are formed. [ 25 ] For all formerly reported devices, however, only basic learning functionality has been demonstrated, for example, hysteresis loop and on/off switching. Literature reports indicate the possibility of scaling liquid state memristors down to nanoscale (30 nm size of the liquid well) providing that non‐volatile solvents are used.…”

“…Literature reports indicate the possibility of scaling liquid state memristors down to nanoscale (30 nm size of the liquid well) providing that non‐volatile solvents are used. [ 25 ]…”

Dynamic Nonlinear Behavior of Ionic Liquid-Based Reservoir Computing Devices

“…Furthermore, the material properties of ILs can be systematically controlled via the selection and combination of anions and cations that comprise IL as well as by dissolving various metal salts in the IL as many metal ions can exist stably in an IL. Previously, we successfully used metal redox reactions to control the data volatility of conducting-bridge memory-based memristors using the copper ion valence in ILs . However, the IL cations that form the inner Helmholtz layer on the anode surface prevented Cu ions from approaching the anode.…”

“…Previously, we successfully used metal redox reactions to control the data volatility of conductingbridge memory-based memristors 17 using the copper ion valence in ILs. 18 However, the IL cations that form the inner Helmholtz layer on the anode surface prevented Cu ions from approaching the anode. The solvated IL, a composite of Cu(Tf 2 N) 2 and 2,5,8,11-tetraoxadodecane (G3) [Cu(Tf 2 N) 2 / G3 = 1:1], allowed easy access of Cu 2+ to the anode, as the ions were coordinated by electrically neutral G3 molecules.…”

Temperature Driven Current–Voltage Characteristics of Ionic Liquid Type Intelligent Connection Device

“…species added to the IL enables the control of the data volatility of CBRAM [14]. A physical reservoir device with a time-series data treatment function and a high-dimensional feature space is also a feasible candidate of its fading property [15], [16].…”