Sn–3Ag–0.5Cu/TiO2/Ti wire-tube structure with memristive response by ultrasonic soldering

Abstract

High-performance memristors have become the next generation of memory devices with potential application to ultra-high-speed, large-capacity, high-density computing requirements. However, devices with low operating voltage, high switching ratio, and long cycle life have not yet been achieved. A novel Sn–3Ag–0.5Cu/TiO2/Ti wire-tube memristor was fabricated using ultrasonic soldering. Ultrasound application changes the wetting conditions of the filler by using the instantaneous high temperature and pressure generated by ultrasonic cavitation, which induces Sn–3Ag–0.5Cu filler metal into anodized TiO2 nanotubes to prepare a wire-tube structure. The Sn–3Ag–0.5Cu/TiO2/Ti device showed bipolar hysteresis with a clear storage window. The maximum switching ratio was 33, which is slightly lower than the value of 36 for a Ag/TiO2/Ti device made using a conventional anodizing method. Seventeen cycles were achieved, which is 143% higher that of the Ag/TiO2/Ti device. The operating voltage of the Cu–3Ag–0.5Cu/TiO2/Ti device was significantly lower than that of the Ag/TiO2/Ti device. The structure and electrochemical performance of the device was evaluated by Raman spectrometry (LAMAN), X-ray photoelectron spectroscopy (XPS) and Electrochemical impendence spectroscopy (EIS) analysis. Formation of the conductive channels of the TiO2 wire-tube structure memristor was studied using transmission electron microscopy and high-resolution transmission electron microscopy, and a model of the mechanism of formation of the conductive filaments was established.