Uniform and Repeatable Cold-Wall Chemical Vapor Deposition Synthesis of Single-Layer MoS₂

A cold-wall chemical vapor deposition method for growing MoS₂ that allows independent control over all deposition parameters is described. Ar carrier gas flow rate and pressure, substrate temperature, and the temperatures of the individual solid-source precursors can all be independently varied during growth onto 100-nm-thick SiO₂ films on Si substrates. Individually optimizing each deposition parameter enables formation of islanded, single-layer MoS₂ films with excellent run-to-run repeatability in coverage and uniformity over several square millimeter areas. Auger electron spectroscopy (AES) and Rutherford backscattering spectrometry were used to quantify the elemental composition of the films. Film morphology was analyzed using scanning electron microscopy (SEM). This analysis indicates that excess Mo deposits on the SiO₂ substrate without incorporating into the stoichiometric single-layer MoS₂ clusters imaged by SEM. In addition, the amount of S detected using AES is nearly identical to the amount required to form the MoS₂ islands.