Improved resistive switching stability of Pt/ZnO/CoOx/ZnO/Pt structure for nonvolatile memory devices

For Pt(Ag)/ZnO single-layer/Pt structure, random 10 formation and rupture of conductive filaments composed by oxygen vacancies or metallic ions often cause dispersion problems of resistive switching (RS) parameters, which is disadvantageous to devices application. In this study, ZnO/CoO (x) /ZnO (ZCZ) tri-layers were utilized as the switching layers to investigate their RS properties as compared with ZnO-based single-layer devices. It is interestingly noted that Pt/ZCZ/Pt devices show quite stable bipolar RS behaviors with little resistance value fluctuations compared to Ag/ZCZ/Pt devices and Pt(Ag)/ZnO/Pt devices, which minimize the dispersion of the resistances of RS. This highly stable RS effect of Pt/ZCZ/Pt structure would be promising for high density memory devices.