Spatially Textured Strained Engineering of WSe₂ on Dielectric Silk Fibroin for Enhanced Optoelectronic Performance

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Nanostrain patterning in 2D transition metal dichalcogenides (TMDs) can improve electronic and optoelectronic properties.
• Existing methods lack controllable localized strain, high-density integration, and efficient integration with field-effect transistors (FETs) for electric field tunability.

Purpose of the Study:

• To achieve controllable nanostrain patterning in WSe2 FETs for enhanced carrier mobility and photocurrent.
• To investigate the effects of nanostrain on electronic structure and optical properties.
• To demonstrate efficient electric field tunability of strain-induced effects.

Main Methods:

• Utilized thermal scanning probe lithography and silk fibroin (SF) for nanostrain patterning.
• Fabricated and characterized monolayer and bilayer WSe2 FETs.
• Analyzed the impact of nanostrain on carrier mobility, electronic structure, and optical properties.

Main Results:

• Confirmed nanostrain presence and its influence on electronic and optical properties.
• Demonstrated enhanced carrier mobility in bilayer WSe2 FETs on SF dielectric due to strain-induced band gap narrowing and suppressed nonradiative recombination.
• Observed reduced exciton binding energy and induced built-in electric field, facilitating trion formation and exciton multiplication, leading to significantly enhanced photocurrent tunable by electrostatic gating.

Conclusions:

• Nanostrain patterning in WSe2 FETs offers a viable strategy for enhancing device performance.
• The developed method enables controllable strain distribution and integration with FETs.
• This approach provides a blueprint for miniaturizing and integrating multifunctional nanoscale devices.