Defect Engineering in Single-Layer MoS₂ Using Heavy Ion Irradiation

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Transition metal dichalcogenides (TMDs) exhibit remarkable optical, electronic, magnetic, and catalytic properties.
• Defect engineering in TMDs is crucial for developing advanced functionalities and enhancing device performance.
• Controllable defect creation and understanding their structure-property relationships remain significant challenges.

Purpose of the Study:

• To investigate the impact of controlled defect densities on the properties of single-layer molybdenum disulfide (MoS2).
• To establish a correlation between defect nature and the resulting functionalities in MoS2.
• To explore the potential of defect engineering for improving MoS2-based applications.

Main Methods:

• Generation of controlled defect densities in single-layer MoS2 using 500 keV Au irradiation at various ion fluences.
• Characterization of introduced defects, primarily sulfur vacancies.
• Analysis of changes in photoluminescence characteristics and electrocatalytic behavior of MoS2 with varying defect densities.

Main Results:

• Ion irradiation successfully introduced sulfur vacancies in MoS2 with controllable densities.
• Photoluminescence spectra of MoS2 showed a blueshift followed by a redshift with increasing defect density, attributed to electron transfer with adsorbed oxygen.
• Hydrogen evolution reaction activity of MoS2 was significantly enhanced due to defect-induced modifications in atomic hydrogen adsorption.

Conclusions:

• Controlled introduction of sulfur vacancies via ion irradiation is an effective strategy for tuning MoS2 properties.
• Defect engineering in MoS2 can lead to significant improvements in photoluminescence and electrocatalytic performance.
• The study provides insights into defect-property correlations, paving the way for tailored MoS2-based devices.