Gate-Tunable Multiband van der Waals Photodetector and Polarization Sensor.

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Developing single photodetectors with tunable wavelengths and polarization sensitivity is challenging using traditional epitaxial films.
• Multifunctional photosensors are crucial for diverse optical applications, including imaging, sensing, and telecommunications.

Purpose of the Study:

• To engineer a multifunctional, high-performance photosensor using all van der Waals (vdW) materials.
• To achieve gate-tunable spectral response and polarization sensitivity in a single device.

Main Methods:

• Fabrication of a photodetector utilizing stacked van der Waals materials.
• Electrical field manipulation of photocurrent generation in active layers.
• Characterization of spectral response, polarization sensitivity, detectivity, and operation speed.

Main Results:

• Demonstrated a gate-tunable spectral response switchable between near-infrared/visible and short-/midwave infrared at room temperature.
• Achieved switchable linear polarization sensitivity (horizontal, vertical, nonpolarizing) in the telecommunication O-band.
• Reported high detectivity (>10^9 cmHz^1/2W^-1) and fast operation speed (approx. 1 MHz).

Conclusions:

• The developed vdW photodetector offers unprecedented multifunctionality and performance for optical applications.
• The device's tunable spectral and polarization characteristics enable novel sensing and imaging capabilities.
• Potential for dual visible and infrared imaging applications is highlighted.