High-on/off-ratio graphene nanoconstriction field-effect transistor.

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Monolayer graphene field-effect transistors (GFETs) are promising for next-generation electronics.
• Achieving critical dimensions below 10 nm for GFETs remains a significant challenge for conventional nanofabrication.

Purpose of the Study:

• To report a novel method for patterning monolayer graphene nanoconstriction field-effect transistors (NCFETs) with dimensions below 10 nm.
• To demonstrate the formation of a confinement-induced energy gap in NCFETs and achieve high on/off ratios.

Main Methods:

• Utilizing feedback-controlled electromigration (FCE) to create a precise constriction in a gold etch mask.
• Patterning the gold etch mask using conventional lithography, followed by FCE for sub-10 nm feature definition.
• Fabricating monolayer graphene nanoconstriction field-effect transistors (NCFETs) using the FCE-patterned etch mask.

Main Results:

• Successfully patterned NCFETs with critical dimensions below 10 nm.
• Observed a confinement-induced energy gap opening as NCFET width decreased, indicated by a sharp increase in the on/off ratio.
• Achieved room-temperature on/off ratios greater than 1000 for the narrowest NCFETs.

Conclusions:

• Feedback-controlled electromigration enables the fabrication of sub-10 nm graphene nanoconstrictions, overcoming limitations of conventional nanolithography.
• The observed confinement-induced energy gap and high on/off ratios demonstrate the potential of NCFETs for high-performance electronic applications.
• This work presents the first report of large room-temperature on/off ratios for patterned graphene FETs fabricated with this method.