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The recent progress of selector and self-rectifying devices for resistive randomaccess memory applications is reviewed. In particular, the performance of crossbar arrays based on resistive switching (RS) devices, the sneak-path current issue, and possible solutions is discussed. The parameters and requirements of selector devices are elucidated here, and several types of selector devices, such as a transistor-assisted transistor-one resistor, unipolar one diode-one resistor, bipolar one selector-one resistor, and threshold switching selectors, are comprehensively discussed. In the case of self-rectifying devices, the recent progress in complementary RS devices, vacancy-modulated conductive oxide-based devices, and tunneling barrier-based RS devices is reviewed. The switching mechanisms and the geometrical configuration of the selector and self-rectifying RS devices are emphasized. Furthermore, comparative assessments of the different devices are evaluated. Finally, an overview of the gaps in previously reported devices is presented and some key improvements for future research direction suggested.

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In recent years, many metal oxides have been rigorously studied to be employed as solid electrolytes for resistive switching (RS) devices. Among these solid electrolytes, lanthanum oxide (La2O3) is comparatively less explored for RS applications. Given this, the present work focuses on the electrodeposition of La2O3 switching layers and the investigation of their RS properties for memory and neuromorphic computing applications. Initially, the electrodeposited La2O3 switching layers are thoroughly characterized by various analytical techniques. The electrochemical impedance spectroscopy (EIS) and Mott–Schottky techniques are probed to understand the in situ electrodeposition, RS mechanism, and n‐type semiconducting nature of the fabricated La2O3 switching layers. All the fabricated devices exhibit bipolar RS characteristics with excellent endurance and stable retention. Moreover, the device mimics the various bio‐synaptic properties such as potentiation‐depression, excitatory post‐synaptic currents, and paired‐pulse facilitation. It is demonstrated that the fabricated devices are non‐ideal memristors based on double‐valued charge‐flux characteristics. The switching variation of the device is studied using the Weibull distribution technique and modeled and predicted by the time series analysis technique. Based on electrical and EIS results, a possible filamentary‐based RS mechanism is suggested. The present results assert that La2O3 is a promising solid electrolyte for memory and brain‐inspired applications.

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Since the discovery of graphene, two-dimensional (2D) materials have gained wide attention, owing to their appealing properties for various technological applications. Etched from their parent MAX phases, MXene is a...

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Many thin film-based devices with solid electrolytes have been studied for memristive applications. Herein, we report a simple and facile way to fabricate solution-based, low-cost, and discrete two-terminal memristive devices using the KMnO4 solution. The water and methanol were used as a solvent to prepare different concentrations of KMnO4 to carry out the optimization study. Furthermore, the effect of KMnO4 concentration with aqueous and methanol solvents was studied with the help of current-voltage, device charge, charge-flux, and cyclic endurance properties. Interestingly, all developed devices show the asymmetric time-domain charge and double valued charge-flux properties, suggesting that aqueous KMnO4 and methanol-KMnO4 based devices are non-ideal memristors or memristive devices. The statistical measures such as cumulative probability and coefficient of variation are reported for the memristive devices. The possible switching mechanism of the discrete memristive was tried to explain with the UV-visible spectrum and theoretical framework. The optimized device was further studied using the cyclic voltammogram, Bode plot, and Nyquist plot. An equivalent circuit was derived for the optimized discrete memristive device using electrochemical impendence spectroscopy results. The results of the present investigation are beneficial to develop programmable analog circuits, volatile memory, and synaptic devices using discrete memristive devices.