Combination of conductive filaments and Schottky behavior in multifunctional Sn1−xCuxO2−δ memristor

Resistive switching behaviors of SnO2 films are largely improved by Cu acceptor doping. At a suitable Cu2+ concentration, a high ON/OFF resistance ratio (104), good endurance (104) and long retention (104 s) are achieved in the Cu/SnO2:Cu/Pt sandwich structure with the modulation of carriers and oxygen vacancies. As a memristor, the resistive switching can be triggered by one pulse or a train of pulses, and the latter mode could simulate the long-term potentiation of biological synapses. Moreover, the multi-resistance states during the reset process demonstrate a combination of abrupt and incremental resistive switching. The peculiar conductive behavior of the devices is considered to result from the cooperation of conductive filaments and Schottky barrier, with the oxygen vacancies serving as the bridge. These studies are significant for higher density storage and cognitive computing in future.