Analog Memristive Characteristics of Square Shaped Lanthanum Oxide Nanoplates Layered Device

Characteristics of Synaptic Function of Mesoporous Silica-Titania and Mesoporous Titania Lateral Electrode Devices

In this paper, we have fabricated non-volatile memory resistive switching (RS) devices and analyzed analog memristive characteristics using lateral electrodes with mesoporous silica-titania (meso-ST) and mesoporous titania (meso-T) layers. For the planar-type device having two parallel electrodes, current-voltage (I-V) curves and pulse-driven current changes could reveal successful long-term potentiation (LTP) along with long-term depression (LTD), respectively, by the RS active mesoporous two layers for 20~100 μm length. Through mechanism characterization using chemical analysis, non-filamental memristive behavior unlike the conventional metal electroforming was identified. Additionally, high performance of the synaptic operations could be also accomplished such that a high current of 10^-6 Amp level could occur despite a wide electrode spacing and short pulse spike biases under ambient condition with moderate humidity (RH 30~50%). Moreover, it was confirmed that rectifying characteristics were observed during the I-V measurement, which was a representative feature of dual functionality of selection diode and the analog RS device for both meso-ST and meso-T devices. The memristive and synaptic functions along with the rectification property could facilitate a chance of potential implementation of the meso-ST and meso-T devices to neuromorphic electronics platform.

Tunable Multilevel Data Storage Bioresistive Random Access Memory Device Based on Egg Albumen and Carbon Nanotubes

In this paper, a tuneable multilevel data storage bioresistive memory device is prepared from a composite of multiwalled carbon nanotubes (MWCNTs) and egg albumen (EA). By changing the concentration of MWCNTs incorporated into the egg albumen film, the switching current ratio of aluminium/egg albumen:multiwalled carbon nanotubes/indium tin oxide (Al/EA:MWCNT/ITO) for resistive random access memory increases as the concentration of MWCNTs decreases. The device can achieve continuous bipolar switching that is repeated 100 times per cell with stable resistance for 104 s and a clear storage window under 2.5 × 104 continuous pulses. Changing the current limit of the device to obtain low-state resistance values of different states achieves multivalue storage. The mechanism of conduction can be explained by the oxygen vacancies and the smaller number of iron atoms that are working together to form and fracture conductive filaments. The device is nonvolatile and stable for use in rewritable memory due to the adjustable switch ratio, adjustable voltage, and nanometre size, and it can be integrated into circuits with different power consumption requirements. Therefore, it has broad application prospects in the fields of data storage and neural networks.

Resistive Switching Characteristics Improved by Visible-Light Irradiation in a Cs2AgBiBr6-Based Memory Device

Light-modulated lead-free perovskites-based memristors, combining photoresponse and memory, are promising as multifunctional devices. In this work, lead-free double perovskite Cs₂AgBiBr₆ films with dense surfaces and uniform grains were prepared by the low-temperature sol-gel method on indium tin oxide (ITO) substrates. A memory device based on a lead-free double perovskite Cs₂AgBiBr₆ film, Pt/Cs₂AgBiBr₆/ITO/glass, presents obvious bipolar resistive switching behavior. The R_OFF/R_ON ratio under 445 nm wavelength light illumination is ~100 times greater than that in darkness. A long retention capability (>2400 s) and cycle-to-cycle consistency (>500 times) were observed in this device under light illumination. The resistive switching behavior is primarily attributed to the trap-controlled space-charge-limited current mechanism caused by bromine vacancies in the Cs₂AgBiBr₆ medium layer. Light modulates resistive states by regulating the condition of photo-generated carriers and changing the Schottky-like barrier of the Pt/Cs₂AgBiBr₆ interface under bias voltage sweeping.