Waveguide-integrated van der Waals heterostructure photodetector at telecom wavelengths with high speed and high responsivity


Intensive efforts have been devoted to the exploration of new optoelectronic devices based on two-dimensional transition-metal dichalcogenides (TMDCs) owing to their strong light–matter interaction and distinctive material properties. In particular, photodetectors featuring both high-speed and high-responsivity performance are of great interest for a vast number of applications such as high-data-rate interconnects operated at standardized telecom wavelengths. Yet, the intrinsically small carrier mobilities of TMDCs become a bottleneck for high-speed application use. Here, we present high-performance vertical van der Waals heterostructure-based photodetectors integrated on a silicon photonics platform. Our vertical MoTe2–graphene heterostructure design minimizes the carrier transit path length in TMDCs and enables a record-high measured bandwidth of at least 24 GHz under a moderate bias voltage of –3 V. Applying a higher bias or employing thinner MoTe2 flakes boosts the bandwidth even to 50 GHz. Simultaneously, our device reaches a high external responsivity of 0.2 A W–1 for incident light at 1,300 nm, benefiting from the integrated waveguide design. Our studies shed light on performance trade-offs and present design guidelines for fast and efficient devices. The combination of two-diemensional heterostructures and integrated guided-wave nano photonics defines an attractive platform to realize high-performance optoelectronic devices, such as photodetectors, light-emitting devices and electro-optic modulators.

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Fig. 1: Vertical MoTe2-graphene heterostructure photodetector.
Fig. 2: Electrical characteristics of the photodetectors.
Fig. 3: Steady-state photoresponse of a waveguide photodetector featuring a MoTe2 thickness of 45 nm.
Fig. 4: Dynamic characterization of the photodetectors.
Fig. 5: Comparison of devices with different MoTe2 thicknesses and under different bias conditions.

Data availability

The data that support the findings of this study are available from the corresponding author on reasonable request.


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This research was supported by the Swiss National Science Foundation (grant no. 200021_165841). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan, A3 Foresight by JSPS and the CREST (grant no. JPMJCR15F3), JST. This work was carried out partially at the Binnig and Rohrer Nanotechnology Centre and the FIRST Centre for Micro- and Nanotechnology at ETH Zürich.

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N.F., P.M., J.L. and L.N. conceived the project. N.F. and P.M. designed and fabricated the devices and performed the experiments. Y.S. contributed to the experiments. A.E. contributed to the device fabrication. T.T. and K.W. synthesized the hBN crystals. N.F., P.M., J.L. and L.N. analysed the data and co-wrote the manuscript, with support from all authors.

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Correspondence to Ping Ma or Juerg Leuthold or Lukas Novotny.

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Supplementary Information

Supplementary Figs. 1–8, Table 9, discussion and refs. 1–12.

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Flöry, N., Ma, P., Salamin, Y. et al. Waveguide-integrated van der Waals heterostructure photodetector at telecom wavelengths with high speed and high responsivity. Nat. Nanotechnol. 15, 118–124 (2020). https://doi.org/10.1038/s41565-019-0602-z

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