Recent Developments and Perspectives for Memristive Devices Based on Metal Oxide Nanowires

Memristive devices are considered one of the most promising candidates to overcome technological limitations for realizing next-generation memories, logic applications, and neuromorphic systems in the modern nanoelectronics and information technology. Despite the continuous efforts, understanding the resistive switching mechanism underlying memristive/neuromorphic behavior still represents a challenge. Metal oxide nanowire-based memristors appear suitable model systems for a deeper understanding of the involved physical/chemical phenomena due the possibility for localizing and investigating the switching mechanism. In practical aspects, nanowire-based devices can be grown using a bottom-up approach, thus being considered reliable candidates for going beyond the current scaling limitations of the top-down approach by the standard lithography. In addition, taking into advantage of the high surface-to-volume ratio of these nanostructures, new device functionalities can be achieved by exploiting surface effects. In the literature, a variety of nanowire-based devices such as single nanowires, nanowire arrays, and networks are reported to exhibit memristive behavior, explained by different switching mechanisms. This work provides a comparative review and a comprehensive analysis of device performances and physical phenomena responsible for memristive and neuromorphic behavior in such nanostructures. The analysis of the state-of-art of memristor devices based on nanowires and nanorods represent a milestone toward the development of nanowire-based artificial neural networks.