Tuning the memristive response of TaO$_x$-based devices with Ag Nanoparticles

TL;DR

This study demonstrates that embedding Ag nanoparticles in TaO$_x$ memristors effectively tunes their resistive switching behavior, reduces variability, and enhances stability by controlling interface dynamics without altering the oxide structure.

Contribution

It introduces a novel approach of using Ag nanoparticles for defect engineering to control and improve memristor switching stability and reproducibility.

Findings

AgNPs suppress one hysteresis loop, resulting in a single switching mode.

Devices with AgNPs show reduced cycle-to-cycle variability and improved endurance.

Numerical models accurately reproduce experimental behavior with AgNPs coverage.

Abstract

Defect engineering is a key strategy to control resistive switching (RS) in oxide-based memristive devices, where oxygen vacancy (OV) dynamics governs filament formation and rupture. We investigate the effect of Ag nanoparticles (AgNPs) embedded in the top electrode of Pt/Ta2O5/TaO2/Pt memristors and analyze their RS behavior and statistical stability. Devices without AgNPs exhibit two hysteresis switching loops (HSLs) with opposite chiralities, originating from the participation of the Pt/Ta2O5 top interface and the Ta2O5/TaO2 bottom interface. Incorporating AgNPs reduces the overall device resistance and selectively suppresses one loop, yielding a single, well-defined switching mode. Moreover, devices incorporating Ag-NPs show markedly reduced cycle-to-cycle variability of the high-resistance state, as confirmed by Weibull analysis, indicating improved endurance and switching reproducibility. Within a filamentary RS framework, we attribute this behavior to local metallization of the top interface by AgNPs, which partially inhibit OV transport and confines the RS dynamics to the bottom interface. Numerical simulations with the Oxygen Vacancy Resistive Network (OVRN) model succesfully reproduce the experimental HSLs, statistical trends, and tunable ON/OFF ratios with AgNPs coverage. These findings demonstrate that targeted interface metallization via metallic nanoparticles provides an effective route to control multi-interface RS dynamics and improve switching stability in without modifying the oxide architecture.