Experimental study for selection of electrode material for ZnO-based memristors

The fabrication and characterisation of 400 nm-thick zinc oxide (ZnO)-based memristor devices with platinum (Pt), chromium (Cr) and gold (Au) metal electrodes are presented. The effect of these electrode materials on the performance of ZnO-based memristors has been experimentally studied. Metal/ZnO contact limits the memristor switching mechanism, dominating during the resistive switching. It is observed that the ZnO-based memristor with the Pt electrode shows a better hysteresis compared to Cr and Au metal electrodes. In the case of the Pt electrode, a current ratio of six times in magnitude is observed between the high resistive state and low resistive state at 1 V, where a maximum current density value of 1.25 A/cm² is measured. The capacitance of these devices strongly depends on the charge distributed on the surface. Therefore, the capacitance-voltage (C-V) behaviour can be used to understand the charge distribution, under various bias conditions. The C-V behaviour of the Pt memristor, so as to understand the contact interface, where the maximum capacitance of 2.3 × 10^-7 F/cm² is obtained at 0 V, is also explained.