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arXiv · 2605.23646

Graphene-based Photodetector with Engineered Hot Carrier Cooling Dynamics

Yishu Huang·Anand Nivedan·Florian Ludwig·Bohai Liu·Michiel Debaets·Steven Brems·Hai I. Wang·Alessandro Principi·Dries Van Thourhout·Christian Haffner·Aron W. Cummings·Klaas-Jan Tielrooij
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Abstract

Graphene has emerged as a promising material for integration into silicon photonics, owing to its ultrafast and broadband photoresponse without the need for an external bias voltage. This photoresponse relies on the photo-thermoelectric effect created by hot carriers. A key factor underlying the performance of graphene photodetectors is the cooling dynamics of these hot carriers. In this work, we engineer these dynamics in a WSe2-graphene-WSe2 waveguide-integrated photodetector. In particular, by introducing proximity screening by a nearby graphite layer to this structure, we prolong the hot-carrier cooling time, leading to an enhanced photoresponse. We characterize the cooling dynamics under continuous-wave laser excitation by employing a photomixing technique, revealing an increase in the cooling time by up to a factor of four. Direct photoresponse measurements show that the internal photoresponsivity improves by approximately 50%. Together, these results demonstrate the potential of proximity screening to enhance the performance of graphene-based photodetectors on an integrated photonics platform.

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Yishu Huang, Anand Nivedan, Florian Ludwig, Bohai Liu, Michiel Debaets, Steven Brems, Hai I. Wang, Alessandro Principi, Dries Van Thourhout, Christian Haffner, Aron W. Cummings, Klaas-Jan Tielrooij. 2026-05-22. Graphene-based Photodetector with Engineered Hot Carrier Cooling Dynamics. https://arxiv.org/abs/2605.23646

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