Synchronized Photoluminescence and Electrical Mobility Enhancement in 2D WS₂ through Sequence-Specific Chemical...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Chemistry

Background:

• Two-dimensional (2D) semiconducting dichalcogenides are promising for advanced electronics and photonics.
• Defects in these materials limit carrier mobility and photoluminescence (PL), hindering device performance.
• Existing defect passivation strategies show inconsistent results due to poor understanding of surface chemistry.

Purpose of the Study:

• To develop a novel chemical passivation protocol for 2D dichalcogenides.
• To investigate the underlying atomic-level passivation mechanisms.
• To establish a new quality benchmark for 2D tungsten disulfide (WS2) materials.

Main Methods:

• Development of a sequence-specific chemical passivation (SSCP) protocol using 2-furanmethanothiol (FSH) and Li-TFSI.
• Characterization of WS2 monolayers using ultrafast transient absorption spectroscopy (TA) and Hard X-ray photoelectron spectroscopy (HAXPES).
• Theoretical investigation using density functional theory (DFT) calculations.

Main Results:

• The SSCP protocol achieved a synchronized 100-fold enhancement in carrier mobility and PL in WS2 monolayers.
• Demonstrated synergistic passivation of both neutral and charged sulfur vacancies (SVs) at the atomic level.
• Established a new semiconductor quality benchmark for 2D WS2.

Conclusions:

• Uncovered novel binding chemistry for effective defect passivation in 2D dichalcogenides.
• The SSCP protocol offers a reliable method to significantly boost the performance of 2D WS2.
• Paved the way for developing sustainable 2D semiconductor technologies.