CuO/ZnO memristors via oxygen or metal migration controlled by electrodes

We carry out a comparative study on resistive switching in CuO/ZnO bilayer films; both samples grown Pt and Ag electrodes show bipolar switching behaviors. The two kinds of current-voltage curves reveal the different resistive switching behaviors in Pt/CuO/ZnO/Pt and Ag/CuO/ZnO/Pt, respectively. We conjecture that the formation and rupture of conducting filaments are responsible for the switching effect. Filaments induced by migration of oxygen ions are responsible for resistive switching with the Pt electrode. In contrast, resistive switching with the Ag electrode is attributed to the migration of metal cations and the corresponding electrochemical metallization. It is also inferred that the characteristic nature of the conducting filaments influences many aspects of switching characteristics, including the switching voltages and cycling variations at room temperature.