High-speed black phosphorus field-effect transistors approaching ballistic limit

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanoelectronics

Background:

• Atomically thin black phosphorus (BP) is a promising material for next-generation electronics due to its tunable bandgap and high carrier mobility.
• Optimizing BP device performance requires addressing transport properties under high electric fields.

Purpose of the Study:

• To enhance the transport properties of black phosphorus (BP) devices through interface engineering and optimized transport orientation.
• To achieve record-breaking performance metrics in BP transistors for advanced electronic applications.

Main Methods:

• Interface engineering using high-quality HfLaO dielectrics.
• Designing device channels along the armchair direction with lower effective mass.
• Fabricating and characterizing 100-nm back-gated BP transistors.

Main Results:

• Achieved record-high drive current of 1.2 mA/μm at 300 K and 1.6 mA/μm at 20 K.
• Demonstrated a hole saturation velocity of 1.5 × 10⁷ cm/s at room temperature.
• Observed record ballistic efficiencies of 36% at 300 K and 79% at 20 K, verified by simulations.

Conclusions:

• Interface engineering and transport orientation significantly improve BP device performance.
• The achieved performance surpasses existing two-dimensional semiconductor transistors.
• BP transistors exhibit excellent potential for high-performance electronic devices.