Ultracompact on-chip coiled waveguide-integrated photodetectors enabled by 2D materials with enhanced responsivity

Area of Science:

• Photonics and Materials Science
• Optoelectronics and Nanotechnology

Background:

• High-performance on-chip photodetectors are essential for integrated photonic systems.
• Two-dimensional (2D) materials offer enhanced light-matter interactions due to their unique properties.
• Waveguide integration is a key strategy for on-chip photodetector development.

Purpose of the Study:

• To design and demonstrate an ultracompact photodetector with enhanced light-matter interaction.
• To investigate the performance of a coiled waveguide architecture for MoS2-based photodetectors.
• To improve responsivity and external quantum efficiency in on-chip photodetectors.

Main Methods:

• Simulated and experimentally demonstrated a photodetector integrating MoS2 with a coiled silicon nitride waveguide.
• Compared the performance of the coiled waveguide structure with a conventional straight waveguide.
• Fabricated and characterized the ultracompact photodetector under optimal operating conditions.

Main Results:

• The coiled waveguide architecture significantly extended optical interaction length, increasing responsivity by over 500% compared to a straight waveguide.
• Achieved excellent photodetector performance: 600 mAW-1 responsivity, 145% external quantum efficiency, and 9.35 × 10^14 AW-3 normalized photocurrent-to-dark current ratio.
• Demonstrated maximized optical absorption and photocurrent generation due to prolonged light-matter interaction.

Conclusions:

• The coiled waveguide architecture is highly effective for maximizing light-matter interaction in MoS2-based photodetectors.
• This approach offers a promising solution for next-generation high-performance integrated photonic systems.
• The study validates the coiled waveguide design for enhanced sensing, optical communication, and light detection applications.