Integrated PbS Colloidal Quantum Dot Photodiodes on Silicon Nitride Waveguides

Chao Pang; Yu-Hao Deng; Ezat Kheradmand; Nithin Poonkottil; Robin Petit; Lukas Elsinger; Christophe Detavernier; Pieter Geiregat; Zeger Hens; Dries Van Thourhout

doi:10.1021/acsphotonics.3c00945

Integrated PbS Colloidal Quantum Dot Photodiodes on Silicon Nitride Waveguides

ACS Photonics. 2023 Nov 20;10(12):4215-4224. doi: 10.1021/acsphotonics.3c00945. eCollection 2023 Dec 20.

Authors

Chao Pang^{1

2}, Yu-Hao Deng^{2

3}, Ezat Kheradmand^{2

3}, Nithin Poonkottil^{2

4}, Robin Petit^{2

4}, Lukas Elsinger^{1

2}, Christophe Detavernier^{2

4}, Pieter Geiregat^{2

3}, Zeger Hens^{2

3}, Dries Van Thourhout^{1

2}

Affiliations

¹ Photonics Research Group, Ghent University - imec, 9052 Ghent, Belgium.
² NB Photonics, Ghent University, 9052 Ghent, Belgium.
³ Physics and Chemistry of Nanostructures Group, Ghent University, 9000 Ghent, Belgium.
⁴ Conformal Coating of Nanomaterials Group, Ghent University, 9000 Ghent, Belgium.

PMID: 38145169
PMCID: PMC10741659 (available on 2024-11-20)
DOI: 10.1021/acsphotonics.3c00945

Abstract

Colloidal quantum dots (QDs) have become a versatile optoelectronic material for emitting and detecting light that can overcome the limitations of a range of electronic and photonic technology platforms. Photonic integrated circuits (PICs), for example, face the persistent challenge of combining active materials with passive circuitry ideally suited for guiding light. Here, we demonstrate the integration of photodiodes (PDs) based on PbS QDs on silicon nitride waveguides (WG). Analyzing planar QDPDs first, we argue that the main limitation WG-coupled QDPDs face is detector saturation induced by the high optical power density of the guided light. Using the cladding thickness and waveguide width as design parameters, we mitigate this issue, and we demonstrate WG-QDPDs with an external quantum efficiency of 67.5% at 1275 nm that exhibit a linear photoresponse for input powers up to 400 nW. In the next step, we demonstrate a compact infrared spectrometer by integrating these WG-QDPDs on the output channels of an arrayed waveguide grating demultiplexer. This work provides a path toward a low-cost PD solution for PICs, which are attractive for large-scale production.