Real-Time TEM Observation of the Microstructural Evolution in Silver Nanowires under Heating and Electrical Biasing

Silver nanowires (Ag NWs) are of interest for a variety of emerging technologies, such as transparent electrodes, nanoscale heaters, and neuromorphic devices, thanks to their excellent electrical conductivity, flexibility, and tunable nanoscale properties. However, the current understanding of the phenomena underpinning their behavior under electrical stimulation and heating, including failure and reconfiguration effects, is largely based on lab-scale device measurements, offering only indirect insights into the underlying mechanisms. In this work, in situ biasing and heating transmission electron microscopy imaging are performed on individual Ag NWs to directly investigate their morphological and structural evolution under controlled electrical and thermal stress in a vacuum. The results indicate that electrical NW breakdown is dominated by electromigration and localized Joule heating, leading to nanogap formation primarily at the cathode, while thermal decomposition proceeds more gradually along the crystallographic planes. They also provide direct evidence of rewiring phenomena, i.e., the electrically induced reconnection of a previously broken NW, highlighting the self-healing, adaptive, and memristive behavior of the NW under the action of an applied electrical stimulation. Altogether, this work offers fundamental insights into failure and reconfiguration mechanisms at the single NW level, informing the design of Ag NW-based components for flexible electronics, sensors, and neuromorphic systems.