Progress in the Characterizations and Understanding of Conducting Filaments in Resistive Switching Devices

Characterizations of resistive switching (RS) devices, especially through direct, in situ methodologies, provide valuable information that could lead to improved insights into the device switching mechanism and device design and optimization. Here, we discuss the characterization efforts on resistive switching devices to date, with emphasis on direct transmission electron microscopy observations on conducting filament formation and growth dynamics. Other characterization techniques used in filament analysis such as spectroscopic and topographic characterizations will also be covered. In the end, we will discuss challenges to be addressed and advances that are needed to further our understanding of dynamic ionic, electronic, and structural effects involved in the RS process.