Local Heat Dissipation of Ag Nanowire Networks Examined with Scanning Thermal Microscopy

Abstract

Silver nanowires (AgNWs) have shown remarkable potential as materials for transparent conductive electrodes in next-generation flexible devices because of their excellent physical properties. However, despite this advantage, breakdown occurs when AgNWs are exposed to a high temperature and current flow, which has been a significant obstacle. Therefore, a thorough understanding of the breakdown based on local thermal and electrical analyses is essential for developing new devices for various electronic applications. As it is difficult to measure the local heat dissipation occurring at a nanoscale, the breakdown process has not yet been analyzed in detail through an experimental approach. In this study, the local breakdown process due to Joule heat and concentrated current density was examined using scanning thermal microscopy when current flowed through a AgNW network. The results showed that the nanowire breaks at ∼453 K, which is lower than the previously reported temperature of breakdown that occurred only via environmental heating. In this study, we found that the AgNW network can be broken down at temperatures below ∼500 K because the atomic flux due to the combined effects of Rayleigh instability and electromigration is applied to atoms on the surface when the nanowires operate electrically. This work proposes that electromigration and Rayleigh instability should be considered in the design of AgNW devices.