Graphene photodetectors for high-speed optical communications


Although silicon has dominated solid-state electronics for more than four decades, a variety of other materials are used in photonic devices to expand the wavelength range of operation and improve performance. For example, gallium-nitride based materials enable light emission at blue and ultraviolet wavelengths1, and high index contrast silicon-on-insulator facilitates ultradense photonic devices2,3. Here, we report the first use of a photodetector based on graphene4,5, a two-dimensional carbon material, in a 10 Gbit s−1 optical data link. In this interdigitated metal–graphene–metal photodetector, an asymmetric metallization scheme is adopted to break the mirror symmetry of the internal electric-field profile in conventional graphene field-effect transistor channels6,7,8,9, allowing for efficient photodetection. A maximum external photoresponsivity of 6.1 mA W−1 is achieved at a wavelength of 1.55 µm. Owing to the unique band structure of graphene10,11 and extensive developments in graphene electronics12,13 and wafer-scale synthesis13, graphene-based integrated electronic–photonic circuits with an operational wavelength range spanning 300 nm to 6 µm (and possibly beyond) can be expected in the future.

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Figure 1: Metal–graphene–metal (MGM) photodetectors with asymmetric metal contacts.
Figure 2: Photocurrent imaging in MGM photodetectors with excitation of 632.8 nm.
Figure 3: Photocurrent generation, high-frequency characterization of the MGM photodetector, and operation of the MGM photodetector at a data rate of 10 Gbit s−1 with 1.55-µm light excitation.
Figure 4: Source–drain bias (VB) dependence of the MGM photoresponse.


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The authors would like to thank D.B. Farmer, B.A. Ek and J.J. Bucchignano for technical assistance. We are grateful to Y.A. Vlasov, W.M.J. Green and S. Assefa for lending us part of their equipment. T.M. acknowledges financial support by the Austrian Science Fund FWF (Erwin Schrödinger fellowship J2705-N16).

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All authors contributed to the preparation of this manuscript.

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Correspondence to Thomas Mueller or Fengnian Xia or Phaedon Avouris.

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Mueller, T., Xia, F. & Avouris, P. Graphene photodetectors for high-speed optical communications. Nature Photon 4, 297–301 (2010).

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