Dilute Rhenium Doping and its Impact on Defects in MoS₂

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• 2D transition metal dichalcogenides (TMDs) like MoS2 are crucial for advanced electronic and optoelectronic devices.
• Controlling defects in TMDs is essential for optimizing device performance.

Purpose of the Study:

• To investigate the impact of substitutional rhenium (Re) doping on molybdenum disulfide (MoS2) monolayers.
• To understand how Re doping affects defect density, growth dynamics, and electronic properties of MoS2.

Main Methods:

• Substitutional doping of MoS2 monolayers with Re using metal-organic chemical vapor deposition (MOCVD).
• Characterization of defect density using photoluminescence (PL) spectroscopy.
• Computational modeling using *ab initio* methods to study defect formation energies.
• Fabrication and testing of field-effect transistors (FETs) based on Re-doped MoS2.

Main Results:

• Controllable Re doping of MoS2 down to 500 ppm was achieved.
• Trace amounts of Re reduced sulfur site defect density by 5-10×.
• Re doping suppressed defect photoluminescence by 6× at 0.05 at.% and completely quenched it at 1 at.% Re.
• Re-MoS2 transistors showed a 2× increase in drain current and carrier mobility compared to undoped MoS2.

Conclusions:

• Substitutional Re doping is an effective strategy to reduce sulfur vacancies in MoS2 monolayers.
• Reduced defect density leads to improved carrier transport and enhanced device performance.
• This study provides insights into dopant-controlled growth dynamics for high-quality 2D materials.