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

Abstract

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.