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

Transition metal dichalcogenides (TMDs), particularly monolayer TMDs with direct bandgap properties, are key to advancing optoelectronic device technology. WSe stands out due to its adjustable carrier transport, making it a prime candidate for optoelectronic applications. This study explores monolayer WSe synthesis via H-assisted CVD, focusing on how carrier gas flow rate affects WSe quality. A comprehensive characterization of monolayer WSe was conducted using OM (optical microscope), Raman spectroscopy, PL spectroscopy, AFM, SEM, XPS, HRTEM, and XRD. It was found that H incorporation and flow rate critically influence WSe'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 WSe synthesis, offering insights for fabricating monolayer TMDs like WS, MoSe, and MoS, and facilitating their broader integration into optoelectronic devices.