Tunable threshold resistive switching characteristics of Pt-Fe2O3 core-shell nanoparticle assembly by space charge effect

Tunable threshold resistive switching characteristics of Pt-Fe 2 O 3 core-shell nanoparticle (NP) assembly were investigated. The colloidal Pt-Fe 2 O 3 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-Fe 2 O 3 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. Pt-Fe 2 O 3 core-shell nanoparticle assembly shows the threshold resistive switching with tunable threshold voltage by space charges stored in nanoparticles.