Pulsed laser dewetting of Au films: Experiments and modeling of nanoscale behavior

Ultrathin metal film dewetting continues to grow in interest as a simple means to make nanostructures with well-defined properties. Here, we explored the quantitative thickness-dependent dewetting behavior of Au films under nanosecond (ns) pulsed laser melting on glass substrates. The trend in particle spacing and diameter in the thickness range of 3-16 nm was consistent with predictions of the classical spinodal dewetting theory. The early stage dewetting morphology of Au changed from bicontinuous-type to hole-like at a thickness between 8.5 and 10 nm, and computational modeling of nonlinear dewetting dynamics also captured the bicontinuous morphology and its evolution quite well. The thermal gradient forces were found to be significantly weaker than dispersive forces in Au due to its large effective Hamaker coefficient. This also resulted in Au dewetting length scales being significantly smaller than those of other metals such as Ag and Co.