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Integrated PbS Colloidal Quantum Dot Photodiodes on Silicon Nitride Waveguides
Chao Pang1,2, Yu-Hao Deng2,3, Ezat Kheradmand2,3
1Photonics Research Group, Ghent University - imec, 9052 Ghent, Belgium.
ACS Photonics
|December 25, 2023
Summary
Researchers integrated lead sulfide colloidal quantum dot (QD) photodiodes onto silicon nitride waveguides. This overcomes limitations in photonic integrated circuits, enabling efficient light detection for compact spectrometers.
Area of Science:
- Optoelectronics
- Materials Science
- Nanotechnology
Background:
- Colloidal quantum dots (QDs) offer versatile optoelectronic properties for light emission and detection.
- Photonic integrated circuits (PICs) require integration of active materials with passive light-guiding circuitry.
- Existing PICs face challenges in combining efficient light detection with waveguide technology.
Purpose of the Study:
- To demonstrate the integration of lead sulfide (PbS) QD-based photodiodes (PDs) onto silicon nitride waveguides (WGs).
- To address detector saturation issues in waveguide-coupled QD photodetectors (QDPDs).
- To develop a compact infrared spectrometer using integrated QDPDs.
Main Methods:
- Fabrication of PbS QD photodiodes directly on silicon nitride waveguides.
- Analysis of planar QD photodiode performance and waveguide-coupled QD photodiode limitations.
- Optimization of waveguide cladding thickness and width to mitigate detector saturation.
- Integration of optimized WG-QDPDs with an arrayed waveguide grating demultiplexer.
Main Results:
- Demonstrated waveguide-coupled QD photodiode (WG-QDPD) with 67.5% external quantum efficiency at 1275 nm.
- Achieved a linear photoresponse for input powers up to 400 nW by mitigating saturation.
- Successfully integrated WG-QDPDs into a compact infrared spectrometer.
- Showcased a viable low-cost photodetector solution for PICs.
Conclusions:
- PbS QD photodetectors can be effectively integrated with silicon nitride waveguides for photonic applications.
- Design parameter optimization successfully addressed detector saturation challenges.
- This integration enables the development of compact, low-cost infrared spectrometers and other PICs.
- The work paves the way for scalable, cost-effective photodetector solutions in photonic integrated circuits.
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