Dry transfer method for suspended graphene on lift-off-resist: simple ballistic devices with Fabry-Pérot interference

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanoelectronics

Background:

• Suspended graphene structures are crucial for advanced nanoelectronic devices.
• Existing fabrication methods often face challenges in scalability and achieving high-quality, clean devices.
• Weak coupling to the environment is essential for ultra-fast device response.

Purpose of the Study:

• To demonstrate a robust and scalable fabrication scheme for clean suspended graphene nanoelectronic devices.
• To investigate the electronic properties of suspended graphene, including doping behavior and charge transport.
• To enable novel electronic applications through high-quality, two-dimensional material structures.

Main Methods:

• Utilizing chemical-vapor-deposition (CVD)-grown graphene.
• Employing a dry transfer method onto lift-off-resist-coated substrates.
• Implementing current annealing at 4 K to modify doping characteristics.

Main Results:

• Fabricated devices showed tunable doping from positive (p) to negative (n) via current annealing.
• Achieved ultra-low residual charge density (9 × 10^8 cm^-2) and high mobility (1.9 × 10^5 cm^2 V^-1 s^-1).
• Observed clear Fabry-Pérot conductance oscillations, indicating ballistic electron transport and agreement with Klein tunneling theory.

Conclusions:

• The demonstrated fabrication scheme is simple, scalable, and robust.
• The high-quality suspended graphene devices exhibit excellent electronic properties.
• This method significantly enhances the potential for producing suspended, high-performance two-dimensional material structures for future electronic applications.