Reduced Defect Density in MOCVD-Grown MoS₂ by Manipulating the Precursor Phase.

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Two-dimensional transition metal dichalcogenides like molybdenum disulfide (MoS2) are vital for next-generation electronics and optoelectronics.
• Sulfur vacancies in MoS2 films cause defects, leading to poor photoluminescence and n-type doping, which degrade material quality.

Purpose of the Study:

• To develop an improved synthesis method for large-area, high-quality MoS2 films.
• To investigate the impact of reduced sulfur vacancies on MoS2 film properties and device performance.

Main Methods:

• Utilized single-phase liquid precursors for metal-organic chemical vapor deposition (MOCVD) to grow MoS2 films.
• Fabricated photodetectors (PDs) using the synthesized MoS2 films.
• Analyzed the photoresponsivity, photoresponse speed, and electrical characteristics of the fabricated PDs.

Main Results:

• Achieved improved photoresponsivity and faster photoresponse in PDs within the 405-637 nm spectral range compared to conventional MOCVD.
• Observed a positive threshold voltage shift in MoS2 thin films, indicating reduced sulfur vacancy defects.
• Demonstrated significantly enhanced synthesis of monolayer MoS2.

Conclusions:

• The new MOCVD method using liquid precursors effectively reduces sulfur vacancies in MoS2 films.
• This method leads to superior electronic and optoelectronic properties, enabling high-performance photodetectors.
• The improved synthesis technique expands the potential applications of high-quality, atomically thin MoS2 in large-scale devices.