Large-area two-dimensional MoO₃ as a high-κ dielectric for van der Waals integration

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Large-area, high-quality dielectrics are crucial for integrating two-dimensional (2D) transistors.
• Conventional dielectrics present deposition challenges for 2D material integration.
• Van der Waals (vdW) dielectrics offer an attractive alternative for 2D device fabrication.

Purpose of the Study:

• To grow large-area, single-crystalline molybdenum trioxide (MoO3) with uniform thickness.
• To characterize the dielectric properties of MoO3 for 2D transistor applications.
• To demonstrate the integration of MoO3 as a dielectric in 2D field-effect transistors (FETs) and integrated circuits.

Main Methods:

• Growth of large-area, single-crystalline MoO3 crystals.
• Electrical characterization of MoO3 dielectric properties, including dielectric constant, gate leakage, and breakdown field.
• Fabrication and testing of top-gated MoS2 transistors utilizing MoO3 as the dielectric.
• Demonstration of MoO3-based integrated circuits and complementary metal-oxide-semiconductor (CMOS) inverters.

Main Results:

• Achieved millimeter-scale single-crystalline MoO3 with uniform thickness.
• Measured a high dielectric constant (~18.5), low gate leakage (~10^-2 A cm^-2 at 3.0 MV cm^-1), and a high breakdown field (~26.75 MV cm^-1).
• Fabricated MoS2 transistors with excellent performance: average subthreshold swing of ~71 mV dec^-1 and on/off current ratio > 10^8.
• Successfully demonstrated MoO3-based integrated circuits and low-power CMOS inverters.

Conclusions:

• Single-crystalline MoO3 is a promising high-performance vdW dielectric for large-area 2D electronics.
• The demonstrated MoO3 dielectric enables high-performance 2D transistors and integrated circuits.
• This work facilitates the advancement of low-power, high-density 2D electronic devices and systems.