Lithium ion trapping mechanism of SiO2 in LiCoO2 based memristors

Pt/LiCoO₂/SiO₂/Si stacks with different SiO₂ thicknesses are fabricated and the influence of SiO₂ on memristive behavior is investigated. It is demonstrated that SiO₂ can serve as Li ion trapping layer benefiting device retention, and the thickness of SiO₂ must be controlled to avoid large SET voltage and state instability. Simulation model based on Nernst potential and diffusion potential is postulated for electromotive force in LiCoO₂ based memristors. The simulation results show that SiO₂ trapping layer decreases the total electromotive field of device and thereby prevents Li ions from migrating back to LiCoO₂. This model shows a good agreement with experimental data and reveals the Li ion trapping mechanism of SiO₂ in LiCoO₂ based memristors.