Electrical reliability and breakdown mechanisms in single-walled carbon nanotubes

We show that single-walled carbon nanotubes can carry current densities >;1 MA/cm
²
for several hours but degrade over time at rates that depend on initial input power. Above a current threshold maximum, we observe large scale physical migration at the CNT-Au electrode interface, which results in Au voids as large as 300 nm in diameter and nearby mounds 3× as tall as the original 50 nm structure. We suggest that the likely mechanism for this void and mound growth is either localized melting, thermomigration, electromigration, or some combination of these. We also show two unique end-of-life breakdown mechanisms for CNTs, a classical fracture via resistive breakdown, and a physically intact but nonconducting failure mode.