Understanding Substrate Effects on Two-Dimensional MoS2 Growth: a Kinetic Monte Carlo Approach

Abstract: Controlling the morphology of two-dimensional (2D) transition metal dichalcogenides (TMDs) plays a key role in their applications. Although chemical vapor deposition can achieve wafer-scale growth of 2D TMDs, a comprehensive theoretical framework for effective growth optimization is lacking. Atomistic modeling methods offer a promising approach to delve into the intricate dynamics underlying the growth. In this study, we employ kinetic Monte Carlo (kMC) simulations to identify crucial parameters that govern the morphology of MoS2 flakes grown on diverse substrates. Our simulations reveal that large adsorption rates significantly enhance growth speed, which however necessitates rapid edge migration to achieve compact triangles. Substrate etching can tune the adsorption-desorption process of adatoms and enable preferential growth within a specific substrate region, controlling the flake morphology. This study unravels the complex dynamics governing 2D TMD morphology, offering a theoretical framework for decision-making in the design and optimization of TMD synthesis processes.