Impact of Carrier Gas Flow Rate on the Synthesis of Monolayer WSe2 via Hydrogen-Assisted Chemical Vapor Deposition

Abstract

Transition metal dichalcogenides (TMDs), particularly monolayer TMDs with direct bandgap properties, are key to advancing optoelectronic device technology. WSe2 stands out due to its adjustable carrier transport, making it a prime candidate for optoelectronic applications. This study explores monolayer WSe2 synthesis via H2-assisted CVD, focusing on how carrier gas flow rate affects WSe2 quality. A comprehensive characterization of monolayer WSe2 was conducted using OM (optical microscope), Raman spectroscopy, PL spectroscopy, AFM, SEM, XPS, HRTEM, and XRD. It was found that H2 incorporation and flow rate critically influence WSe2’s growth and structural integrity, with low flow rates favoring precursor concentration for product formation and high rates causing disintegration of existing structures. This research accentuates the significance of fine-tuning the carrier gas flow rate for optimizing monolayer WSe2 synthesis, offering insights for fabricating monolayer TMDs like WS2, MoSe2, and MoS2, and facilitating their broader integration into optoelectronic devices.