High-performance van der Waals stacked transistors based on ultrathin GaPS₄ dielectrics

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• High-performance field-effect transistors (FETs) require advanced gate dielectric materials.
• Two-dimensional (2D) materials offer unique electronic properties for next-generation devices.

Purpose of the Study:

• To synthesize and characterize few-layer gallium thiophosphate (GaPS4) as a potential high-κ gate dielectric.
• To fabricate and evaluate 2D van der Waals heterostructure FETs using GaPS4.

Main Methods:

• Mechanical exfoliation of bulk GaPS4 to obtain few-layer flakes.
• Fabrication of 2D FETs with GaPS4 as the dielectric and MoS2 as the channel.
• Electrical characterization of the fabricated FETs.

Main Results:

• Few-layer GaPS4 exhibits a relative dielectric constant of ~5.3.
• Fabricated FETs demonstrate a high on-off ratio (>10^7) and low subthreshold swing (80 mV/decade).
• Atomically smooth GaPS4 flakes were utilized as the top-gate dielectric.

Conclusions:

• Few-layer GaPS4 is a promising high-κ dielectric material for 2D transistors.
• This research contributes to the development of high-κ 2D dielectrics.
• The findings pave the way for advanced electronic device fabrication.