Resistive switching behavior, mechanism and synaptic characteristics in TiO2 nanosheets grown on Ti plate by hydrothermal method

In this work, the hydrothermal approach is employed to develop TiO2 nanosheets on Ti plate. Resistive switching devices are fabricated by depositing a layer of Al on the TiO2 nanosheets. X-ray diffraction (XRD) analysis suggested that the anatase phase is dominant in the developed TiO2 nanosheets. Scanning electron microscopy (SEM) pictures showed that well adherent and homogeneous TiO2 nanosheets were successfully grown on the Ti plate. X-ray photoelectron spectroscopy (XPS) confirmed a certain number of oxygen vacancies existed in the TiO2 nanosheets. And the electrical performance of TiO2 nanosheets based memristor devices is examined. This device displayed electroforming-free bipolar resistive switching behavior, and a stable ON/OFF ratio of ∼102 and a retention period over 106 s were obtained. It was demonstrated that the resistive switching mechanism of the TiO2 nanosheets memristor devices arises from Fowler-Nordheim tunneling during positive bias region and Schottky Emission during negative bias region. Furthermore, the device shows more obvious rectified behavior with the increase of SET voltage. Meanwhile, the “analog” switching behaviors of TiO2 nanosheets based memristor devices were also studied.