Robust nanopatterning by laser-induced dewetting of metal nanofilms

TL;DR

This study demonstrates that laser-induced dewetting of nanoscopic metal films can produce spatially ordered, monodisperse nanoparticles with predictable size and spacing, offering a robust method for nanopatterning.

Contribution

It introduces a controllable laser-based technique for nanopattern formation in metal films, revealing the role of hydrodynamic instability in ordering.

Findings

Nanopatterns with short-range order are formed via laser dewetting.

Particle size and spacing depend on film thickness, not laser energy.

The process yields monomodal size distribution of nanoparticles.

Abstract

We have observed nanopattern formation with robust and controllable spatial ordering by laser-induced dewetting in nanoscopic metal films. Pattern evolution in Co film of thickness 1\leq h\leq8 nm on SiO_{2} was achieved under multiple pulse irradiation using a 9 ns pulse laser. Dewetting leads to the formation of cellular patterns which evolve into polygons that eventually break up into nanoparticles with monomodal size distribution and short range ordering in nearest-neighbour spacing R. Spatial ordering was attributed to a hydrodynamic thin film instability and resulted in a predictable variation of R and particle diameter D with h. The length scales R and D were found to be independent of the laser energy. These results suggest that spatially ordered metal nanoparticles can be robustly assembled by laser-induced dewetting.