Covalent Nitrogen Doping and Compressive Strain in MoS2 by Remote N2 Plasma Exposure.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Controllable doping of 2D materials like molybdenum disulfide (MoS2) is crucial for advanced electronic devices.
• Achieving ideal device performance in heterojunctions and p-n homojunctions requires precise doping strategies.

Purpose of the Study:

• To develop an effective method for nitrogen doping of MoS2.
• To investigate the doping mechanism and its effect on the material's properties.
• To explore the relationship between doping and induced strain.

Main Methods:

• Remote N2 plasma surface treatment of MoS2.
• In situ X-ray photoelectron spectroscopy (XPS) for surface chemistry analysis.
• Electrical characterization to determine doping type and concentration.
• First-principles calculations to support experimental findings.

Main Results:

• Successful doping of MoS2 with covalently bonded nitrogen was achieved.
• Nitrogen acts as a p-type dopant in MoS2, consistent with theoretical predictions.
• Substitutional doping by nitrogen induces compressive strain in the MoS2 lattice, a novel observation.
• A correlation between nitrogen doping concentration and the magnitude of compressive strain was established.

Conclusions:

• Remote N2 plasma treatment is an effective strategy for controllable p-type doping of MoS2.
• Substitutional nitrogen doping induces compressive strain in MoS2, offering new avenues for strain engineering in 2D materials.
• The findings provide fundamental insights into doping mechanisms and strain effects in transition metal dichalcogenides.