Pressure-Dependent Shape and Edge Configurations of MoS₂ by Kinetic Monte Carlo Simulation.

Abstract

Understanding the influence of precursor pressures is crucial for optimizing the properties of MoS₂ grown through the chemical vapor deposition (CVD) process. In this study, we use kinetic Monte Carlo (KMC) simulations to investigate how varying the pressures of molybdenum (<i>P</i>_Mo) and sulfur (<i>P</i>_S) impacts the structural properties of MoS₂, such as grain shape and edge configurations. The simulations differentiate three distinct regimes─growth, steady-state, and etching─each defined by specific <i>P</i>_Mo, <i>P</i>_S, and the most probable atomic sites for filling or etching. We further explore how these regimes influence the atomic configuration of MoS₂, particularly the formation of different edge structures like sulfur zigzag (ZZ_S), molybdenum zigzag (ZZ_Mo), and their respective derivatives. A pressure diagram based on the equations of state and most probable atomic sites was constructed for each regime and validated by comparing predicted ZZ-derived edges to experimental observations. Additionally, the study examines the impact of etching on various line defects, providing insights into the evolution of the MoS₂ edges during the CVD process. These findings underscore the importance of controlling both growth and cessation phases in the CVD process to customize edge configurations, with significant implications for chemical functionalization, catalysis, and the electronic properties of transition metal dichalcogenides.