Resistive switching in ZnO/MoOx bilayer for non-volatile memory applications

Memory technologies are essential for transferring and preserving data. As the digital age progressed, memory device size, speed and efficiency were tuned to address the new demands. Resistive random access memory (RRAM) devices are promising candidates for future memory applications and have many advantages, such as scaling, speed, and endurance over conventional flash memory. In this work, bilayer metal oxide (MoOx/ZnO) devices are fabricated with Ag and ITO as top and bottom electrodes and their resistive switching characteristics are investigated for non-volatile memory applications. I–V characteristics of the device are analysed for the characteristic pinched hysteresis loop where bipolar switching has been observed with set voltage at 1.1 V and reset voltage at -\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$-$$\end{document} 0.8 V. The field-dependent migration of oxygen vacancies in metal oxide layers accounts for the bipolar switching mechanism. The conduction mechanism for ITO/ZnO/MoOx/Ag device is studied, revealing ohmic conduction in the low voltage region while space charge limited conduction dominates in the high voltage region. Furthermore, the fabricated device shows excellent retention. Conclusively, this study suggests that the device switches at comparatively lower voltages and has remarkable data retention properties with the addition of MoOx layer over ZnO layer. Since the device shows excellent endurance and data retention properties, the fabricated device can be a good candidate for non-volatile memory applications such as RRAM and neuromorphic computing.