Two-dimensional WS₂ nanoribbon deposition by conversion of pre-patterned amorphous silicon

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Two-dimensional (2D) materials like tungsten disulfide (WS₂) offer unique electronic and optical properties.
• Precise control over the deposition and orientation of 2D materials is crucial for device fabrication.
• Existing methods for WS₂ deposition often lack area selectivity or control over thickness and alignment.

Purpose of the Study:

• To develop a novel method for area selective deposition of 2D WS₂ nanoribbons.
• To achieve tunable thickness and controlled orientation of WS₂ nanoribbons on dielectric substrates.
• To enable the fabrication of advanced electronic and optoelectronic devices using precisely patterned WS₂.

Main Methods:

• Area selective deposition using a complete conversion of a pre-patterned, H-terminated Si layer to metallic W via WF₆.
• In situ sulfidation of the metallic W layer using H₂S at 450 °C to form WS₂ nanoribbons.
• Rapid thermal annealing at 900 °C under inert gas to achieve parallel alignment of WS₂ basal planes.

Main Results:

• Successful area selective deposition of 2D WS₂ nanoribbons down to 20 nm in lateral dimension.
• Tunable nanoribbon thickness controlled by the initial Si layer thickness.
• Random basal plane orientation achieved initially, followed by parallel alignment to the substrate after annealing.
• Demonstration of a method for controlled growth and patterning of WS₂.

Conclusions:

• The presented method enables precise, area selective deposition of WS₂ nanoribbons with tunable thickness.
• Controlled alignment of WS₂ basal planes is achievable through post-deposition annealing.
• This technique provides a pathway for fabricating high-performance 2D WS₂-based devices.