A facile approach for reducing the working voltage of Au/TiO₂/Au nanostructured memristor by enhancing the local electric field.

Memristor devices have attracted tremendous interest for their different applications from nonvolatile data storage to neuromorphic computing units. Exploring the role of surface roughness of bottom electrode (BE)/active layer interface provides useful guidelines for the optimization of the memristor switching performance. This study focussed on the effect of surface roughness of the BE electrode on the switching characteristics of Au/TiO₂/Au three-layer memristor device. An optimized wet-etching treatment conditions was found to modify the surface roughness of the Au BE where the measurment results indicate that the roughness of the Au BE is affected by both duration time and solution concentrations of the wet-etching process. Then we fabricated arrays of TiO₂-based nanostructured memristors sandwiched between two sets of cross-bar Au electrode lines (junction area 900 µm²). The results reaveled a reduction in the working voltages in current-voltage characteristic of the device performance with increasing the surface roughness at the Au(BE)/TiO₂ active layer interface. The set voltage of the device (V_set) significantly decreased from 2.26 V to 1.93 V by increasing the interface roughness from 4.2 nm to 13.1 nm. The present work provides information for better understanding the switching mechanism of titanium dioxide based devices, and it can be inferred that enhancing the roughness of the Au BE/TiO₂ active layer interface leads to a localized non-uniform electric field distribution that plays a vital role in the reducing the energy consumption of the device.