Strain Engineering for Enhancing Carrier Mobility in MoTe₂ Field-Effect Transistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Molybdenum ditelluride (MoTe2) is a promising 2D material for post-silicon electronics due to its silicon-like bandgap.
• MoTe2 offers phase modulation and carrier type control but suffers from instability and low carrier mobility.

Purpose of the Study:

• To develop a deterministic method for enhancing the performance of MoTe2 devices.
• To improve carrier mobility and device stability in MoTe2 field-effect transistors (FETs).

Main Methods:

• Inducing local tensile strain via substrate engineering with hole arrays.
• Utilizing atomic layer deposition (ALD) for Al2O3 dielectric layers and passivation.
• Fabricating MoTe2 FETs with engineered substrates and encapsulation.

Main Results:

• Achieved significantly improved hole and electron mobilities in MoTe2 FETs (up to 130 cm²/Vs and 160 cm²/Vs, respectively).
• Demonstrated up to a 6-fold increase in electron mobility due to local tensile strain.
• Observed a distinct metal-insulator transition in the MoTe2 FETs.

Conclusions:

• The proposed substrate engineering and encapsulation technique effectively enhances carrier mobility in MoTe2.
• This method offers a pathway to overcome limitations of 2D materials for practical electronic applications.
• The study presents a novel approach for improving 2D material-based electronic devices.