Search

This work explores an architecture for nonvolatile resistive random-access memory (RRAM) systems. The study proposes a self-rectifying RRAM device utilizing a two-terminal 1R selector that harmonizes the gate control efficacy of transistors with the inherent simplicity of diode structures. A rivet-like HfO2-based RRAM array is meticulously constructed through atomic layer deposition (ALD), aiming to enhance device performance and retention stability. The conformal fabrication technique of ALD method is critical in achieving uniform coverage of isolation layers and precise electrode placement, which is instrumental in the fabrication of high-performance memory cells. Empirical analyses indicate significant improvements in rectification and ON/OFF ratios compared to existing RRAM models, bolstered by compatibility with established CMOS processes. It reveals that these advances are conducive to scalable, high-density memory integration, positioning the RRAM as a viable contender for future computational applications that require high efficiency and neuromorphic computing capabilities. [ABSTRACT FROM AUTHOR]

An engineering approach was applied to modify the core layers of charge-trapping flash (CTF) memory—the blocking layer, charge-trapping layer, and tunneling layer. The doping of Ti in the charge-trapping layer and the use of Si-doped HfO2 for the tunneling layer could optimize charge capture and leakage control. This design enhances programming and erasing speeds and increases overall device stability by creating more corner fields and using the Coulomb blockade effect. Experimental results demonstrate a larger memory window and better charge retention for the new device at the same charge-trapping layer thickness. These findings signify the advancement of the new CTF memory in balancing fast programming and long-term charge retention. The long-standing contradiction between charge capturing and retention could be partially resolved by using this engineering method. [ABSTRACT FROM AUTHOR]

This study investigates the behavior of memristive devices characterized by oxygen-deficient ZnO and HfZrO films under continuous pulse stimulation. This dynamic reflects the adaptability observed in neural synapses when repeatedly subjected to stress, ultimately resulting in a mitigated response to pressure. Observations show that the conductivity of memristors increases with the augmentation of continuous electrical pulses. However, the momentum of this growth trend gradually diminishes, highlighting the devices' capability to adapt to repetitive pressure. This adjustment correlates with the transition of biological synapses from short-term to persistent memory stages, aligning with the principles of the Ebbinghaus memory model. The architecture of memristors, integrating ZnO and HfZrO in a layered manner, holds promising prospects in replicating the inherent synaptic features found in biological organisms. [ABSTRACT FROM AUTHOR]

The investigation of dual-mode synaptic plasticity was conducted in thin-film transistors (TFTs) featuring an HfSe2 channel, coupled with an oxygen-deficient (OD)-HfO2 layer structure. In these transistors, the application of negative gate pulses resulted in a notable increase in the post-synaptic current, while positive pulses led to a decrease. This distinctive response can be attributed to the dynamic interplay of charge interactions, significantly influenced by the ferroelectric characteristics of the OD-HfO2 layer. The findings from this study highlight the capability of this particular TFT configuration in closely mirroring the intricate functionalities of biological neurons, paving the way for advancements in bio-inspired computing technologies. [ABSTRACT FROM AUTHOR]

The effect of spacer lengths of imidazolium gemini surfactant [C14-n-C14im]Br2 (n = 2, 4, 6) on the equilibrium, thermodynamics and kinetics of Au(III) extraction from hydrochloric acid medium were investigated in this article. The thermodynamic parameters, including the changes in enthalpy (ΔH*), entropy (ΔS*) and Gibbs free energy (ΔG*) were determined. The values of ΔH* demonstrated that the extraction of Au(III) by [C14-n-C14im]Br2 was endothermic at first and exothermic at last. The kinetics study found that extraction rate became faster when the spacer lengths were increased. Moreover, kinetics results demonstrated that the diffusion is the controlling step, and the mass transfer coefficients of Au(III) in the investigated systems indicated that the resistance of mass transfer was smaller when the spacer lengths was longer. The studies of interfacial tension further confirmed the better extractability of [C14-n-C14im]Br2 with longer spacer lengths. Our results reveal efficient and sustainable gold separation. [ABSTRACT FROM AUTHOR]

In the process of recovering platinum group metals by extraction, separation of Pt and Ir is very difficult because Pt(iv) and Ir(iv) show similar chemical properties and extraction behaviours in hydrochloric acid medium. In this paper, a betaine-based ionic liquid [C6bet]Br was firstly applied to the separation of Pt(iv) and Ir(iv). [C6bet]Br showed remarkable precipitation performance of Pt(iv) and Ir(iv). The impactful extraction was realized by importing [C6mim][NTF2] as the hydrophobic phase with extraction efficiencies of ca. 99% and 88% under optimal conditions. A selective reduction process for Ir(iv) was firstly proposed for the separation of these two similar PGMs by using hydroxylamine hydrochloride (NH2OH·HCl). The mechanism of extracting Pt(iv)/Ir(iv) using [C6bet]Br was confirmed to be an anion-exchange process by spectroscopic analysis (UV-Vis, FT-IR, 1H NMR) and the method of continuous variation. The electrostatic potential map of [C6bet]Br was calculated for the first time to confirm the anion-exchange mechanism. 8 M HCl was effective for the back extraction of Pt(iv) and Ir(iv). [ABSTRACT FROM AUTHOR]