Geometric evolution law for modeling strongly anisotropic thin-film morphology

Area of Science:

• Materials Science
• Surface Physics
• Computational Physics

Background:

• Nanoscale thin film morphology is governed by complex surface processes.
• Understanding these dynamics is crucial for materials fabrication and characterization.

Purpose of the Study:

• To investigate the dynamics of two-dimensional thin films considering surface diffusion, attachment-detachment, deposition, and interface kinetics.
• To characterize coarsening events, scaling laws, and identify distinct morphological regimes.

Main Methods:

• Utilized a high-order accurate and efficient numerical method to simulate thin film evolution.
• Analyzed the formation and dynamics of kinks and antikinks.
• Characterized coarsening behavior under varying deposition fluxes and kinetic effects.

Main Results:

• Observed morphologies feature facets separated by kinks and antikinks, with their numbers decreasing over time.
• Confirmed kink-ternary as the sole coarsening event when deposition is present.
• Identified three distinct coarsening regimes: fast coarsening, periodic structure formation, and chaotic evolution.
• Found that attachment-detachment enhances coarsening compared to surface diffusion alone.
• Demonstrated that interface kinetics necessitate reduced deposition flux for non-chaotic coarsening.

Conclusions:

• The interplay of surface diffusion, deposition, and interface kinetics dictates thin film morphology and coarsening dynamics.
• Numerical simulations provide a framework for understanding and predicting thin-film evolution under various conditions.
• Results offer testable predictions for experimental investigations of nanoscale thin films.