Polarization-sensitive broadband photodetector using a black phosphorus vertical p-n junction

Area of Science:

• Optoelectronics
• Materials Science
• Condensed Matter Physics

Background:

• Broadband light detection is crucial for optoelectronics.
• Existing photodetectors using 2D materials like graphene and MoS2 lack polarization sensitivity.
• Polarization-sensitive photodetectors are highly sought after for advanced optical applications.

Purpose of the Study:

• To demonstrate a broadband, polarization-sensitive photodetector.
• To investigate the potential of layered black phosphorus for photodetection.
• To explore the role of optical anisotropy and electric fields in enhancing polarization sensitivity.

Main Methods:

• Fabrication of a photodetector device using layered black phosphorus.
• Characterization of the photodetector's response across a broad spectral range (400 nm to 3,750 nm).
• Investigation of polarization-dependent photodetection using the transistor geometry and gating-induced electric fields.

Main Results:

• Demonstrated a broadband photodetector with polarization sensitivity from ~400 nm to 3,750 nm.
• Attributed polarization sensitivity to the intrinsic linear dichroism and in-plane optical anisotropy of black phosphorus.
• Showcased enhanced photodetection performance through gating-induced electric field separation of photogenerated carriers, reducing recombination.

Conclusions:

• Layered black phosphorus is a promising material for polarization-sensitive broadband photodetection.
• The transistor geometry with gating offers an effective method to enhance linear dichroism photodetection.
• This work opens avenues for novel optical and optoelectronic devices with enhanced functionalities.