Resistive switching behavior in Pt/YSZ/Nb:SrTiO3 heterostructure for nonvolatile multilevel memories

The yittra-stablized zirconia (YSZ) thin film was deposited on a Nb:SrTiO3 (NSTO) substrate by pulsed laser deposition to form a Pt/YSZ/NSTO heterostructure device. This device exhibits high resistive switching ratio of 105 at a read voltage of −0.1 V after applied +3 V/−4 V pulse voltages. Moreover, the resistance states could be reversibly switched among multilevel resistance states by changing the magnitude of Set or Reset pulse voltages, which shows potential application in multilevel nonvolatile memory devices. The RS mechanism of the device could be attributed to the modulation of YSZ/NSTO Schottky-like junction depletion, which is caused by the carrier injection-trapped/detrapped process under the applied electric field.