Unveiling the Correlation between Defects and High Mobility in MoS₂ Monolayers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Semiconductor defects critically influence electronic properties.
• Chalcogen vacancies are key intrinsic defects in transition metal dichalcogenides.
• The precise role of these vacancies in electrical transport requires further elucidation.

Purpose of the Study:

• To investigate the impact of chalcogen vacancies in MoS2 monolayers on their electronic and transport properties.
• To correlate experimental findings with theoretical calculations for a comprehensive understanding.
• To explore defect engineering for tailoring 2D material characteristics.

Main Methods:

• Optical spectroscopy
• Low-temperature electrical transport measurements
• Scanning tunneling microscopy (STM)
• First-principles density functional theory (DFT) calculations

Main Results:

• Disulfur vacancies in MoS2 create shallow donor states near the conduction band.
• These defects facilitate electron hopping conduction, confirmed by transport and STM data.
• DFT calculations show delocalized defect states, supporting n-type doping and hopping.

Conclusions:

• Disulfur vacancies significantly modulate the electrical properties of MoS2.
• Defect engineering, specifically controlling vacancies, can enhance electron mobility in 2D materials.
• This approach offers a pathway for customizing 2D materials for diverse applications.