Study on Resistance Switching Properties of Na0.5Bi0.5TiO3 Thin Films Using Impedance Spectroscopy

The Na0.5Bi0.5TiO3 (NBT) thin films sandwiched between Au electrodes and fluorine-doped tin oxide (FTO) conducting glass were deposited using a sol-gel method. Based on electrochemical workstation measurements, reproducible resistance switching characteristics and negative differential resistances were obtained at room temperature. A local impedance spectroscopy measurement of Au/NBT was performed to reveal the interface-related electrical characteristics. The DC-bias-dependent impedance spectra suggested the occurrence of charge and mass transfer at the interface of the Au/NBT/FTO device. It was proposed that the first and the second ionization of oxygen vacancies are responsible for the conduction in the low-and high-resistance states, respectively. The experimental results showed high potential for nonvolatile memory applications in NBT thin films.