Conduction and switching mechanism in Nb2O5 thin films based resistive switches

We report unipolar resistive switching of Pt/Nb2O5/Al device with orthorhombic crystalline phase prepared by reactive sputtering method. It showed non-volatile reproducible unipolar switching with ON/OFF resistance ratio of 10(3) or higher. The range of SET and RESET voltage was 1.0-2.0V and 0.3-0.8V, respectively, depending on devices and their dimension. The charge carriers followed Ohmic and space-charge-limited conduction (SCLC) behaviour in low-resistance state (LRS) and high-resistance state (HRS), respectively. An impedance spectroscopy analysis as well as a drift and diffusion of oxygen ion vacancy model are presented to explain the conducting filament formation and its rupture during the SET and RESET processes.