Graphene binding on black phosphorus enables high on/off ratios and mobility

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene's high carrier mobility makes it ideal for integrated circuits.
• Achieving high on/off ratios in graphene devices remains a challenge, limiting applications.
• Existing methods often compromise graphene's intrinsic carrier mobility.

Purpose of the Study:

• To enhance on/off switching ratios in graphene monolayers.
• To maintain high carrier mobility in graphene-based devices.
• To explore vertical heterostructures for improved graphene device performance.

Main Methods:

• Fabrication of a vertical heterostructure using graphene and black phosphorus.
• Introduction of localized strain in graphene via current annealing.
• Modulation of black phosphorus conductivity using back-gate voltage.

Main Results:

• A robust off-state was achieved through local current depletion and strain-induced reflective interfaces.
• A parallel channel in strain-free graphene allows for high mobility in the on-state.
• The device demonstrated an on/off voltage ratio exceeding 10^3.
• High carrier mobility of ~8000 cm^2 V^-1 s^-1 was maintained at room temperature.

Conclusions:

• The graphene-black phosphorus heterostructure effectively overcomes the on/off ratio limitations of graphene.
• The device meets low-power criteria for future electronics.
• This approach offers a promising pathway for high-performance graphene-based electronic devices.