Cascading wafer-scale integrated graphene complementary inverters under ambient conditions

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Logic gates are fundamental to digital electronics and require cascading for complex functions.
• Graphene's unique electronic properties make it a promising material for next-generation electronic devices.
• Achieving compatible input/output voltage levels is crucial for cascading logic gates.

Purpose of the Study:

• To demonstrate integrated graphene complementary inverters capable of cascading.
• To achieve signal matching in graphene inverters under ambient conditions.
• To investigate the performance of self-aligned graphene field-effect transistors for logic applications.

Main Methods:

• Fabrication of graphene complementary inverters using wafer-scale chemical vapor deposition (CVD) graphene.
• Integration of monolayer graphene into self-aligned field-effect transistors with top-gate configuration.
• Characterization of inverter performance, including voltage gain and voltage swing, under ambient conditions.

Main Results:

• Demonstrated integrated graphene complementary inverters with identical input and output voltage logic levels, enabling cascading.
• Achieved signal matching under ambient conditions.
• Obtained the highest reported low-frequency voltage gain (Av ~ -5) for top-gated CVD graphene devices operating in air.
• Exhibited a consistent voltage swing of 0.56 V at both input and output.

Conclusions:

• Graphene complementary inverters are viable for cascading and realizing complex logic functions.
• The demonstrated devices offer potential for high-speed digital electronics applications where power dissipation is not a primary constraint.
• Self-aligned field-effect transistors with full-channel gating in CVD graphene are effective for high-gain inverter applications.