Analog-type resistive switching behavior of Au/HfO2/ZnO memristor fabricated on flexible Mica substrate

Analog-type resistive switching (RS) behavior of Au/HfO2/ZnO thin film deposited on flexible Mica substrate is studied. ZnO thin film is deposited on insulating Mica substrate as bottom electrode and buffer layer by magnetron sputtering. And then HfO2 thin film is fabricated by chemical solution deposition method. The device shows diode-like current-voltage (I-V) characteristic, and its conductivity decreases gradually with consecutive sweeping of applied bias. Such resistive switching behavior is similar to the learning process of biological synapse. A model of mobile charges migration and accumulation at interface is constructed to understand the resistive switching mechanism. It is suggested that the change of Schottky barrier height (SBH) is responsible for resistive switching. This study provides guidance to develop HfO2-based memristor for electronic synapse device, but also provides the theoretical model for understanding the physical mechanism of analog-type resistive switching.