Avalanche-Enhanced Infrared Photodetection via Interlayer Absorption in a WSe₂/MoS₂ Heterostructure

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Infrared photodetectors are vital for advanced optical technologies.
• Two-dimensional (2D) heterostructures with specific band alignments offer sub-bandgap infrared detection.
• Current limitations include low responsivity due to weak interlayer optical absorption.

Purpose of the Study:

• To enhance the responsivity of 2D heterostructure-based infrared photodetectors.
• To overcome weak interlayer absorption using avalanche multiplication.
• To demonstrate a scalable approach for sensitive infrared detection.

Main Methods:

• Fabrication of a WSe₂/MoS₂ heterostructure.
• Utilizing interlayer optical transitions for sub-bandgap infrared absorption.
• Implementing avalanche multiplication in a WSe₂ region for gain.

Main Results:

• Demonstrated an interlayer-absorption avalanche photodiode.
• Achieved a 63-fold increase in responsivity under 1,064 nm illumination.
• Reached a maximum responsivity of 1 mA/W.

Conclusions:

• Avalanche multiplication effectively boosts responsivity in interlayer-absorption photodetectors.
• This method provides a scalable pathway for sensitive infrared detection using 2D materials.
• Highlights the potential of 2D semiconductor platforms for infrared sensing applications.