On the Breakup of Patterned Nanoscale Copper Rings into Droplets via Pulsed-Laser-Induced Dewetting: Competing Liquid-Phase Instability and Transport Mechanisms

Abstract

Nanolithographically patterned copper rings were synthesized, and the self-assembly of the rings into orderednanoparticle/nanodrop arrays was accomplished via nanosecond pulsed laser heating above the melt threshold. Theresultant length scale was correlated to the transport and instability growths that occur during the liquid lifetime ofthe melted copper rings. For 13-nm-thick rings, a change in the nanoparticle spacing with the ring width is attributed to atransition from a Raleigh-Plateau instability to a thin film instability because of competition between the cumulativetransport and instability timescales. To explore the competition between instability mechanisms further, we carried outexperiments with 7-nm-thick rings. In agreement with the theoretical predictions, these rings break up in both theazimuthal and radial directions, confirming that a simple hydrodynamic model captures the main features of theprocesses leading to the breakup.