Enhancing Hole Mobility in Monolayer WSe₂ p-Type Field-Effect Transistors via Process-Induced Compression

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Designing advanced electronics beyond silicon requires understanding 2D material properties.
• Heterointegrated 2D materials offer promising avenues for next-generation electronic devices.
• Strain engineering is a key factor influencing interfacial mechanics and electrical performance.

Purpose of the Study:

• To investigate the impact of biaxial compressive strain on the electrical performance of p-type monolayer WSe2 field-effect transistors (FETs).
• To analyze the relationship between applied strain, interfacial mechanics, and enhanced hole mobility.
• To explore the underlying physical mechanisms responsible for strain-induced performance improvements.

Main Methods:

• Fabrication of monolayer WSe2 field-effect transistors (FETs).
• Sequential deposition of AlOx to incrementally apply compressive strain to WSe2 channels.
• In-situ photoluminescence and electrical transport measurements to track device performance under varying strain levels.
• Combined experimental analysis with computational simulations to understand strain effects.

Main Results:

• Significant enhancement in hole mobility, with a factor increase of 340 ± 95% per unit strain (/%ε).
• Substantial increase in on-current, with a factor increase of 460 ± 340% per unit strain (/%ε).
• Simulations identified reduced intervalley scattering between Γ-K valence bands as the primary mechanism for performance enhancement.

Conclusions:

• Compressive strain is a highly effective technique for enhancing the performance of 2D p-type FETs.
• The observed performance enhancement is robust and independent of carrier density, impurity levels, or the dielectric environment.
• Strain engineering offers a powerful, multiplicative approach to device optimization, complementing defect and doping strategies for 2D material-based electronics.