Spray-On Liquid-Metal Electrodes for Graphene Field-Effect Transistors

Area of Science:

• Materials Science
• Nanotechnology
• Electronics Engineering

Background:

• Flexible electronics require advanced interconnects for broader application.
• Liquid-metals are promising for flexible electrodes due to their unique properties.
• Current liquid-metal fabrication methods are complex, slow, and costly.

Purpose of the Study:

• To develop a cost-effective and high-throughput fabrication method for liquid-metal electrodes.
• To demonstrate the efficacy of a spray-on stencil technique for producing flexible graphene field-effect transistors (GFETs).

Main Methods:

• Utilized an inexpensive spray-on stencil technique for depositing liquid-metal Galinstan electrodes.
• Patterned stencils using an automated vinyl cutter on chemical vapor deposition (CVD) graphene.
• Transferred patterned graphene onto polyethylene terephthalate (PET) substrates.

Main Results:

• Achieved a high throughput of 28 transistors in under five minutes on a single graphene sample.
• Demonstrated a 96% yield for fabricated devices, even with channel lengths as small as 50 μm.
• Fabricated GFETs exhibited excellent charge carrier mobilities: 663.5 cm²/(V·s) for holes and 689.9 cm²/(V·s) for electrons.

Conclusions:

• The spray-on stencil method offers a simple, effective, and scalable approach for fabricating flexible electronics.
• This technique significantly reduces complexity and cost associated with liquid-metal electrode deposition.
• The high yield and performance metrics pave the way for mass production of high-performance flexible devices.