Lithium niobate waveguide-integrated Bi2Te3/graphene heterojunction photodetector

We demonstrate an on-chip photodetector by integrating a graphene and topological insulator Bi2Te3 heterostructure on a thin-film lithium niobate waveguide. Lithium niobate on insulator (LNOI) waveguides are fabricated by the photolithography-assisted chemical mechanical etching method. The bismuth...

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Bibliographic Details
Published in:Optics letters 2024-10, Vol.49 (20), p.5969
Main Authors: Yuan, Tingfei, Dong, Qiaonan, Sun, Xinxing, Gao, Lang, Zheng, Yong, Wang, Ke, Wu, Rongbo, Cheng, Ya
Format: Article
Language:English
Subjects:
Absorptivity
Bismuth tellurides
Graphene
Heterojunctions
Heterostructures
Lithium niobates
Photoelectric effect
Photolithography
Photometers
Thin films
Topological insulators
Waveguides
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Summary:We demonstrate an on-chip photodetector by integrating a graphene and topological insulator Bi2Te3 heterostructure on a thin-film lithium niobate waveguide. Lithium niobate on insulator (LNOI) waveguides are fabricated by the photolithography-assisted chemical mechanical etching method. The bismuth telluride (Bi2Te3) and graphene heterostructure design provides enhanced photocurrent due to the effective photocarrier generation. The lithium niobate waveguide-integrated Bi2Te3/graphene heterojunction presents a high absorption coefficient of 2.1 dB/µm. The Bi2Te3/graphene heterojunction photodetector exhibits a responsivity of 2.54 mA/W without external bias at a 1.55 µm wavelength, which is enhancement of sevenfold as compared to the pure graphene-based photodetector. The photodetector has a 3 dB bandwidth of over 4.7 GHz. This work provides a potentially viable method for a self-powered, high responsivity, and fast response of the photodetector integrated with the LNOI photonic platform.
ISSN:0146-9592
1539-4794
1539-4794
DOI:10.1364/OL.540452