Graphene barristor, a triode device with a gate-controlled Schottky barrier

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanoelectronics

Background:

• Graphene electronics research has faced challenges in achieving sufficient on/off current ratios (I(on)/I(off)) with conventional device structures.
• Existing graphene transistors often struggle to meet the performance demands for practical electronic applications due to limitations in current modulation.

Purpose of the Study:

• To overcome the limitations of conventional graphene transistors by developing a novel device structure.
• To achieve a high on/off current ratio in graphene-based active devices.
• To demonstrate the potential of this new device for logic circuit applications.

Main Methods:

• Development of a three-terminal active device: a graphene variable-barrier barristor (GB).
• Fabrication utilizing an atomically sharp interface between graphene and hydrogenated silicon.
• Control of the graphene-silicon Schottky barrier height via gate voltage modulation.

Main Results:

• Achieved a large modulation on the device current with an on/off ratio of 10^5.
• Demonstrated tunability of the Schottky barrier height to 0.2 electron volt due to the absence of Fermi-level pinning.
• Successfully fabricated complementary p- and n-type GBs on 150-mm wafers and integrated them into inverter and half-adder logic circuits.

Conclusions:

• The graphene variable-barrier barristor (GB) offers a viable solution for achieving high on/off ratios in graphene electronics.
• The atomically sharp graphene-silicon interface is crucial for effective barrier modulation and device performance.
• Demonstrated logic circuits highlight the potential of GBs for future nanoelectronic applications.