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

TL;DR

This study uses real-time electron microscopy to observe how silver nanowires change under heat and electrical stress, revealing how they break down and self-repair.

Contribution

The paper provides direct in situ observations of silver nanowire behavior under electrical and thermal stress, revealing failure and self-healing mechanisms at the nanoscale.

Findings

Electrical breakdown in Ag NWs is dominated by electromigration and Joule heating at the cathode.

Thermal decomposition occurs gradually along crystallographic planes.

Electrically induced rewiring demonstrates self-healing and memristive behavior in Ag NWs.

Abstract

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.

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