Tailorable 2D MoS₂ via Oxide Sulfidation for Photodetection and Contact Engineering

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Contact-limited transport hinders performance in two-dimensional semiconductors.
• Developing scalable fabrication methods for high-quality 2D materials is crucial for advanced electronics.

Purpose of the Study:

• To fabricate few-layer molybdenum disulfide (MoS2) films using a controllable oxide-to-sulfide conversion method.
• To investigate the properties and optoelectronic performance of the fabricated MoS2 films.
• To explore contact engineering strategies for enhancing device performance.

Main Methods:

• Fabrication of MoS2 films via sputtering deposition of molybdenum trioxide followed by chemical-vapor sulfidation.
• Characterization using Raman spectroscopy, elemental analysis, and X-ray diffraction.
• Fabrication and testing of MoS2-based photodetector devices.
• Contact engineering through thermal annealing of nickel electrodes.

Main Results:

• High-quality, uniform, and thickness-tunable MoS2 films with consistent interlayer spacing (~0.65 nm) were produced.
• MoS2 devices demonstrated robust photodetection with microampere photocurrents.
• Bilayer MoS2 showed negative photoconductivity, attributed to surface effects.
• Contact annealing significantly improved photocurrent by enhancing carrier injection.

Conclusions:

• The oxide-to-sulfide conversion strategy is a scalable method for producing high-performance MoS2 films.
• This approach enables engineering of layer-dependent properties for transition metal dichalcogenides.
• The findings are significant for advancing optoelectronic applications using 2D materials.