Resistive switching behavior in memristors with TiO2 nanorod arrays of different dimensions

• Published in: Applied surface science 2019-08, Vol.485, p.222-229
• Main Authors: Yu, Yantao, Wang, Chunqi, Jiang, Chao, Abrahams, Isaac, Du, Zuojuan, Zhang, Qiancheng, Sun, Jia, Huang, Xiaozhong
• Format: Article
• Language: English
• Subjects: Area ratio; Memristors; SCLC mechanism; TiO2 nanorod arrays
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.04.119

In this work, memristors based on TiO2 nanorod arrays (TNAs) were fabricated using a hydrothermal synthesis method. The memristors had a structure consisting of a TNA sandwiched between gold and fluorine doped tin oxide (FTO) coated glass. Devices were constructed using TNAs containing nanorods of different height, diameter and area ratio, with different oxygen vacancy concentrations. The devices exhibit resistance switching behavior and the current through the devices is related to the oxygen vacancy concentration and the area ratio of TNAs. When the height of nanorods is around 3 μm or less, the devices perform well with a current that is as low as 10−8 A in the high resistance state (HRS) and 10−4 A in the low resistance state (LRS). It is found that the space charge limited current (SCLC) mechanism associated with the oxygen vacancies explains the current-voltage behavior of these devices in this three layer structure. A schematic model is presented to illustrate the changes in oxygen vacancy concentration and switching processes, including the formation of new oxygen vacancies (triggered vacancies) to explain the large increase in current at the end of the setting process in these devices. [Display omitted] •Bipolar memristor devices of the type Au/TNA/FTO with different TNA morphologies were prepared and investigated.•The area ratio of the TNAs decreased with increasing synthesis temperature from 413 K to 433 K.•The current through the devices is related to the oxygen vacancy concentration and the area ratio of TNAs.•The current-voltage behavior of these TNA based devices was investigated in details and explained by the SCLC mechanism.•A large increase in current at the end of the setting process is attributed to triggered vacancies.