Understanding the switching-off mechanism in Ag+ migration based resistively switching model systems

Different coplanar $\mathrm{Pt}∕\mathrm{Ag}$ structures were prepared by photolithography on $\mathrm{Si}{\mathrm{O}}_2$ substrates, and $\mathrm{Pt}∕{\mathrm{H}}_2\mathrm{O}∕\mathrm{Ag}$ cells were formed by adding de-ionized ${\mathrm{H}}_2\mathrm{O}$ to the coplanar $\mathrm{Pt}∕\mathrm{Ag}$ structures. The $\mathrm{Pt}∕{\mathrm{H}}_2\mathrm{O}∕\mathrm{Ag}$ cell is utilized here as a model system, due to the feasibility of visual inspection of the switching process. Bipolar switching was achieved for the cell. Scanning electron microscopy (SEM) investigations demonstrated that the growth and dissolution of Ag dendrites are responsible for the resistive switching. The Ag dendrite morphology is proposed to be the origin of the asymmetrical dissolution during the switching-off process, hence the bipolar nature of the switching characteristics.