Using Thermal Crowding to Direct Pattern Formation on the Nanoscale

TL;DR

This paper demonstrates how controlling metal deposition and thermal effects can influence pattern formation in nanoscale metal films under laser irradiation.

Contribution

It introduces a self-consistent modeling approach to manipulate nanoscale pattern formation via thermal crowding effects and metal geometry control.

Findings

Depositing additional metal elevates temperature and influences pattern development.

Thermal crowding affects instability growth and pattern evolution.

Modeling enables control over nanoscale fluid instabilities.

Abstract

Metal films and other geometries of nanoscale thickness, when exposed to laser irradiation, melt and evolve as fluids as long as their temperature is sufficiently high. This evolution often leads to pattern formation, which may be influenced strongly by material parameters that are temperature dependent. In addition, the laser heat absorption itself depends on the time-dependent metal thickness. Self-consistent modeling of evolving metal films shows that, by controlling the amount and geometry of deposited metal, one could control the instability development. In particular, depositing additional metal leads to elevated temperatures through the `thermal crowding' effect, which strongly influences the metal film evolution. This influence may proceed via disjoint metal geometries, by heat diffusion through the underlying substrate. Fully self-consistent modeling focusing on the dominant effects, as well as accurate time-dependent simulations, allow us to describe the main features of thermal crowding and provide a route to control fluid instabilities and pattern formation on the nanoscale.