Localized resistive switching in a ZnS–Ag/ZnS double-layer memory

Bipolar resistive-switching memories were demonstrated based on a Ag/ZnS/ITO stack structure, where the electrolyte layer is made into a double-layer structure composed of a Ag-nanoclusters-embedded ZnS layer and a pure ZnS layer. The introduction of Ag-nanoclusters results in thicker Ag conducting filaments (CFs) formed in ZnS–Ag than in ZnS. This difference in CFs' size between two sub-layers makes the resistive switching localized in the ZnS sub-layer. By reducing its thickness, the switching region is reduced and the degree of localization is enhanced. Therefore, compared with the single-layer ZnS memory, the double-layer device shows improved switching uniformity, reduced forming/switching voltages and better endurance. (paper)