# Self-organized metal nanostructures through laser driven thermocapillary convection

## TL;DR

This paper investigates how ultrathin Co metal films on SiO2 surfaces self-organize into nanostructures like nanowires and nanoparticles through laser-induced thermocapillary convection, revealing the underlying physical mechanisms.

## Contribution

It demonstrates the formation of ordered nanostructures in ultrathin metal films via laser-driven thermocapillary flow and instability mechanisms, expanding understanding of laser-induced self-organization.

## Key findings

- Nanowires form and break into ordered nanoparticles.
- Pattern scaling aligns with thermocapillary and Rayleigh-like instabilities.
- Ultrathin films (≤2 nm) undergo spinodal instability leading to nanoparticle formation.

## Abstract

When ultrathin metal films are subjected to multiple cycles of rapid melting and resolidification by a ns pulsed laser, spatially correlated interfacial nanostructures can result from a competition among several possible thin film self-organizing processes. Here we investigate self-organization and the ensuing length scales when Co films (1-8 nm thick) on SiO_{\text{2}} surfaces are repeatedly and rapidly melted by non-uniform (interference) laser irradiation. Pattern evolution produces nanowires, which eventually break-up into nanoparticles exhibiting spatial order in the nearest neighbor spacing, \lambda_{NN2}.The scaling behavior is consistent with pattern formation by thermocapillary flow and a Rayleigh-like instability. For h_{0}\leq2 nm, a hydrodynamic instability of a spinodally unstable film leads to the formation of nanoparticles.