Lattice gas study of thin film growth scenarios and transitions between them: Role of substrate

TL;DR

This study explores thin film growth using lattice gas models, highlighting how substrate interactions influence morphology and transitions, and identifying four global growth scenarios.

Contribution

It introduces two lattice gas models with substrate effects, revealing dynamic layering and flattening transitions in thin film growth.

Findings

Dynamic layering transition occurs at lower substrate attraction than equilibrium transition.

A flattening transition transforms island growth to layer-by-layer growth.

Four global growth scenarios are identified based on roughness evolution.

Abstract

Thin film growth is investigated in two types of lattice gas models where substrate and film particles are different, expressed by unequal interaction energy parameters. The first is of solid-on-solid type, whereas the second type incorporates desorption, diffusion in the gas phase above the film and re-adsorption at the film (appropriate for growth in colloidal systems). The difference between particle-substrate and particle-particle interactions plays a central role for the evolution of the film morphology at intermediate times. The models exhibit a dynamic layering transition which occurs at generally lower substrate attraction strengths than the equilibrium layering transition. A second, flattening transition is found where initial island growth transforms to layer-by-layer growth at intermediate deposition times. Combined with the known roughening behavior in such models for very large deposition times, we present four global growth scenarios, charting out the possible types of roughness evolution.