The unexpected dewetting during growth of silicene flakes with dendritic pyramids

TL;DR

This paper investigates the unusual dewetting growth mode of silicene on graphene, combining experimental microscopy, thermodynamic modeling, and simulations to understand and control the formation of nanostructures and dendritic pyramids.

Contribution

It introduces a comprehensive thermodynamic and kinetic model that explains the anomalous silicene growth mode and offers practical guidelines for improving silicene quality.

Findings

Model accurately reproduces experimental growth patterns

Identifies key thermodynamic factors influencing dewetting

Provides strategies for controlled silicene fabrication

Abstract

Silicene growth on graphene has emerged as a novel method for fabricating silicon-based van der Waals heterostructures. However, the silicene flakes produced in this manner are the result of an exotic growth mode characterized by metastable nanostructures with varying degrees of deviation from equilibrium, with large two-dimensional flakes surrounded by a rim that coexist with small 3D islands, and, at large deposits, thick dendritic pyramids separated by a denuded zone. In order to rationalize and control this growth, a model is derived that revisits the dewetting thermodynamics and considers generally ignored adsorption and step-edge energies. The model is investigated using kinetic Monte-Carlo simulations and mean-field rate equations, and implemented by close inspection of microscopy images. This model perfectly reproduces the experimental outcomes, unveiling an anomalous growth mode, and provides guidelines on experimental conditions for high-quality silicene growth.