Electronic and Optoelectronic Monolayer WSe₂ Devices via Transfer-Free Fabrication Method

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Monolayer transition metal dichalcogenides (TMDs) are essential for advanced electronics and optoelectronics.
• Uniform, large-area crystals are critical for consistent device properties and high yields.
• Current fabrication methods face challenges in achieving large-scale uniformity and device integration.

Purpose of the Study:

• To develop a method for growing high-quality, uniform large-area monolayer WSe2 films.
• To demonstrate a novel transfer-free fabrication process for WSe2-based devices.
• To evaluate the electrical and optoelectronic performance of the fabricated devices.

Main Methods:

• Chemical vapor deposition (CVD) on polycrystalline gold substrates for WSe2 growth.
• Direct fabrication of field-effect transistors (FETs) and photodetectors on as-grown WSe2 films.
• Characterization of WSe2 film uniformity, domain size, and device performance.

Main Results:

• Achieved continuous, large-area monolayer WSe2 films with large domain sizes.
• Fabricated transfer-free WSe2 FETs exhibiting high room-temperature mobility (≈62.95 cm^2 V^-1 s^-1).
• Demonstrated stable WSe2 photodetectors with high photoresponsivity (~1.7 × 10^4 A W^-1) and detectivity (~1.2 × 10^13 Jones).

Conclusions:

• The CVD growth on Au substrates provides a scalable route to high-quality monolayer WSe2.
• The transfer-free fabrication method enables robust device integration with excellent performance.
• This approach offers a promising pathway for large-scale manufacturing of TMD-based electronic and optoelectronic devices.