Polarized photocurrent response in black phosphorus field-effect transistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Few-layer black phosphorus (BP) is a promising material for advanced electronic and optoelectronic devices.
• Understanding charge transport and light interaction in nanoscale BP is crucial for device optimization.

Purpose of the Study:

• To investigate the electrical transport and optoelectronic properties of few-layer black phosphorus field-effect transistors (BP FETs).
• To explore the anisotropic nature and photocurrent generation mechanisms in BP FETs.

Main Methods:

• Fabrication of field-effect transistors using few-layer black phosphorus crystals.
• Conducting spatial-, polarization-, gate-, and bias-dependent photocurrent measurements.
• Analyzing anisotropic features and photocurrent generation mechanisms.

Main Results:

• Black phosphorus field-effect transistors exhibit significant anisotropic photocurrent generation.
• Photocurrent signals are attributed to the photovoltaic effect in the off-state and the photothermoelectric effect in the on-state.
• The observed anisotropy primarily stems from the directional-dependent light absorption of black phosphorus crystals.

Conclusions:

• The study elucidates the distinct photocurrent generation mechanisms in black phosphorus FETs.
• Anisotropic optical absorption in black phosphorus is identified as the key factor for directional photocurrent.
• These findings provide insights for designing high-performance optoelectronic devices based on black phosphorus.