Field-effect transistors based on wafer-scale, highly uniform few-layer p-type WSe2

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Few-layer tungsten diselenide (WSe2) synthesis often yields non-uniform thickness due to domain growth.
• This limits its application in scalable semiconductor technologies.

Purpose of the Study:

• To develop a method for synthesizing wafer-scale, thickness-uniform few-layer p-type WSe2.
• To demonstrate the electrical uniformity of the synthesized WSe2 films.

Main Methods:

• Direct selenization of e-beam evaporated tungsten (W) thin films on SiO2 substrates.
• Wafer-scale Raman mapping to assess thickness uniformity.
• Fabrication and characterization of field-effect transistors (FETs) to evaluate electrical performance.

Main Results:

• Achieved wafer-scale few-layer p-type WSe2 with excellent thickness uniformity across several square centimeters.
• Demonstrated uniform electrical performance in FETs fabricated from the WSe2 films.
• Measured an intrinsic field-effect mobility of 10 cm(2) V(-1) s(-1) at a carrier concentration of 3 × 10(12) cm(-2).

Conclusions:

• Direct selenization offers a scalable route to uniform few-layer WSe2.
• The synthesized WSe2 is suitable for manufacturable semiconductor devices compatible with existing fabrication processes.