Comparison of the MOCVD Growth and Properties of Wafer-Scale Transition Metal Dichalcogenide Epitaxial Monolayers

Epitaxial growth of transition metal dichalcogenides (TMDs) by metalorganic chemical vapor deposition (MOCVD) is a promising method for wafer-scale synthesis of monolayer films. This study focuses on a comparison of the epitaxial growth of MoS2, WS2, and WSe2 monolayers on 2-inch c-plane sapphire substrates using a cold-wall reactor with metal hexacarbonyl and hydride chalcogen sources. Uniform thermofluidic conditions enabled a comparative analysis of nucleation density, domain size, and lateral growth rate across TMD compounds, shedding light on the impact of TMD chemistry on epitaxial growth. Despite the use of chemically analogous precursors such as Mo(CO)6 or W(CO)6 and H2S or H2Se, significant differences in growth behavior are observed. Comprehensive structural, optical, and transport characterizations provide insights into sulfur versus selenium-based TMDs, advancing the understanding of optimized growth conditions for these emerging materials.