Tunable threshold resistive switching characteristics of Pt–Fe2O3 core–shell nanoparticleassembly by space charge effect

Abstract

Tunable threshold resistive switching characteristics of Pt–Fe₂O₃ core–shell nanoparticle (NP) assembly were investigated. The colloidal Pt–Fe₂O₃ core–shell NPs with a Pt core diameter of ∼3 nm and a total diameter of ∼15 nm were chemically synthesized by a one-step process. These NPs were assembled as a layer with a thickness of ∼80 nm by repeated dip-coating between Ti and Pt electrodes on a flexible polyethersulfone (PES) substrate. The Ti/NPs/Pt/PES structure exhibited the threshold switching, i.e. volatile transition from high to low resistance state at a high voltage and vice versa at a low voltage. The current–voltage measurements after charging and discharging NPs revealed that the resistance state and threshold switching voltage of the assembly could be tuned by the space charges stored in high density trap sites of Pt cores in Pt–Fe₂O₃ core–shell NP assembly. These results demonstrated the possible tuning of threshold switching of core–shell NP assembly by the space charge effect, which can be potentially utilized for the tunable selection device element in nonvolatile memory circuits.