In the pursuit of energy-efficient computing, various neuromorphic computing and engineering strategies have emerged. Silver nanowires (Ag NWs) are of particular interest for memristive applications, including neuromorphic architectures based on self-assembled nanowire networks [1].

Emergent behavior in these complex systems arises from resistive switching (RS) phenomena, occurring both within individual NWs and at their junctions. In the first case, this phenomenon is linked to rapture and rewiring of Ag NW by electromigration and/or Joule heating; the electrical connection can then be reestablished by forming of an conductive filament within the gap. In the second case, it is associated with the creation of conductive bridge at intersection of two NWs.

The current understanding of the phenomena underpinning the behavior of such networks is principally based on characterization of pre- and post-electrical stimulation devices and electrical measurements. However, such approaches lack direct insight into the local changes that might occur.

To address this, we performed in situ heating and biasing transmission electron microscopy (TEM) to directly visualize the structural and morphological evolution of single NWs and small NW networks under controlled electrical and thermal stimuli.

We investigated electrical breakdown in single Ag NWs during voltage sweep stimulation. Joule heating and electromigration are the two possible causes of fracture for metal wires during operation and in-situ observation sheds some more light on its mechanisms [2,3]. We also observed in situ the reformation of conductive pathways under applied bias, offering direct experimental evidence of self-healing behavior in metallic NW systems. This rewiring, involving the dissolution and redeposition of silver across the gap, highlights the potential for adaptive and reconfigurable network behavior.

Additionally, we studied the temperature influence on the morphology and structure of the single NWs and of small NW networks. In single Ag NWs, morphological changes were initially observed as the creation of humps and valleys, eventually with rising temperature the NWs break and the rapture continues to enlarge with changes in morphology following the crystalline orientations of preference.

In NW networks, progressive sintering at junctions was observed as the temperature increases. Further increase of the temperature led to formation of fractures, which progressively become larger, until the junction broke. In the context of neuromorphic network this suggests a failure and lose of its percolative pathways.