Sulfur vacancy activated field effect transistors based on ReS2 nanosheets

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Rhenium disulfide (ReS2) is a transition metal dichalcogenide with a unique direct bandgap across all thicknesses.
• Synthesis of high-quality ReS2 nanosheets (NSs) and understanding their properties remain challenging.
• Applications of ReS2 are largely unexplored due to synthesis difficulties.

Purpose of the Study:

• To synthesize high-quality ReS2 NSs using chemical vapor deposition (CVD).
• To investigate the performance of ReS2-based field-effect transistors (FETs).
• To understand the role of intrinsic sulfur vacancies in ReS2 properties and device performance.

Main Methods:

• Chemical vapor deposition (CVD) for ReS2 NS synthesis.
• Fabrication and characterization of ReS2 FET devices.
• Electrical transport measurements from 80 K to 360 K.
• First-principles calculations to analyze defect properties.

Main Results:

• Successful synthesis of high-quality ReS2 NSs.
• Demonstration of ReS2 FETs with a high on/off ratio of ~10^5.
• Identification of intrinsic sulfur vacancies significantly affecting ReS2 FET performance.
• Demonstration of gas sensing (O2, NH3) capabilities of ReS2 NSs at defect sites.

Conclusions:

• Established a reliable method for synthesizing high-quality ReS2 NSs.
• Provided insights into the physical nature of ReS2 FETs, highlighting the role of sulfur vacancies.
• Showcased defect engineering as a route to tailor ReS2 properties for applications like gas sensing.