A brief overview of anodic memristors: fundamentals, classification and properties

Abstract

Memristors have emerged as a promising technology for next-generation memory and neuromorphic computing due to their ability to mimic synaptic behavior and retain previous resistance states, while showing promise as future energy-efficient devices. Various materials have been investigated for resistive switching applications, including valve metals-Hf, Nb, Ta, Ti, etc., which stand out due to their ability to form stable oxide layers with tuneable oxide growth and ability for controlled defect engineering. These properties are crucial for obtaining reliability and scalability in memristive devices. A significant advantage of anodic memristor fabrication in comparison to other methods is the anodization process. It is a simple, costeffective electrochemical method, which can ensure precise control over the oxide thickness, composition, and intrinsic defect structuring. By adjusting anodization parameters, it is possible to influence oxygen vacancy distribution and interfacial properties, thus enhancing resistive switching capabilities such as formation voltage, switching voltage, endurance, and retention. This review provides a detailed evaluation of memristive devices based on anodic oxides. From their fabrication, resistive switching mechanisms, and defect structuring to applications in memory and neuromorphic computing. Furthermore, a comparison of various valve metals and their alloys is presented, identifying their individual advantages and limitations in memristive performance.