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Ultra-broadband photoconductivity in twisted graphene heterostructures with large responsivity


The requirements for broadband photodetection are becoming exceedingly demanding in hyperspectral imaging. While intrinsic photoconductor arrays based on mercury cadmium telluride represent the most sensitive and suitable technology, their optical spectrum imposes a narrow spectral range with a sharp absorption edge that cuts their operation to <25 μm. Here we demonstrate a large ultra-broadband photoconductivity in twisted double bilayer graphene heterostructures spanning the spectral range of 2–100 μm with internal quantum efficiencies of approximately 40% at speeds of 100 kHz. The large response originates from unique properties of twist-decoupled heterostructures including pristine, crystal field-induced terahertz band gaps, parallel photoactive channels and strong photoconductivity enhancements caused by interlayer screening of electronic interactions by respective layers acting as sub-atomic spaced proximity screening gates. Our work demonstrates a rare instance of an intrinsic infrared–terahertz photoconductor that is complementary metal-oxide-semiconductor compatible and array integratable, and introduces twist-decoupled graphene heterostructures as a viable route for engineering gapped graphene photodetectors with three-dimensional scalability.

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Fig. 1: Large photoconductive response in large-angle TDBG.
Fig. 2: Ultra-broadband spectral response from infrared to terahertz wavelengths in TDBG photodetector.
Fig. 3: Strong photoconductivity enhancement in TDBG.
Fig. 4: Photoconductivity mechanism.
Fig. 5: Interlayer screening of e–h collisions in TDBG.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request.

Code availability

All codes used to produce the findings of this study are available from the corresponding authors on reasonable request.


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We thank D. B. Ruiz, S. Castilla, D. De Fazio, M. Amir Ali, G. Li, A. Berdyugin, M. Polini, V. Mkhitaryan, G. Kumar, and I. Torre for technical discussions. We further thank M. Ceccanti for making the illustration presented in Fig. 1a. H.A., K.N. and R.B. acknowledge funding from the European Union’s Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement no. 665884, 713729 and 847517, respectively. S.B.-P. acknowledges funding from the Presidencia de la Agencia Estatal de Investigación within the PRE2020-094404 predoctoral fellowship. G.S. and A.F. gratefully acknowledge funding from the ERC grant CHIC (no. 724344), and J. Faist for discussions. A.P. acknowledges support from the European Union’s Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement no. 873028 and from the Leverhulme Trust under grant agreement RPG-2019-363. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by MEXT Japan with grant no. JPMXP0112101001, JSPS KAKENHI (JP19H05790, JP20H00354 and JP21H05233) and CREST (JPMJCR15F3), JST. R.K.K. acknowledges the EU Horizon 2020 programme under MarieSkłodowska-Curie grants 754510 and 893030 and the FLAG-ERA grant (PhotoTBG, PCI2021-122020-2A), by ICFO, RWTH Aachen and ETHZ/Department of Physics. A.B. acknowledges support from ERC advanced grant no. 692876, MICINN grant no. RTI2018-097953-B-I00 and PID2021-122813OB-I00, AGAUR (grant no. 2017SGR1664), the Fondo Europeo de Desarrollo, the Spanish Ministry of Economy and Competitiveness through Quantum CCAA, EUR2022-134050, and CEX2019-000910-S [MCIN/AEI/10.13039/501100011033], MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1), Fundacio Cellex, Fundacio Mir-Puig, Generalitat de Catalunya through CERCA. F.H.L.K. acknowledges support from the ERC TOPONANOP (726001), Fundació Cellex, Fundació Mir-Puig, Generalitat de Catalunya (CERCA, AGAUR, SGR 1656, program TWIST), the Government of Spain [PID2019-106875GB-I00; PCI2021-122020-2A; PDC2022-133844-I00 (Teracomm); Severo Ochoa CEX2019-000910-S] funded by MCIN/AEI/10.13039/501100011033 and by the European Union NextGenerationEU/PRTR. Furthermore, the research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 881603 (Graphene flagship Core3), 820378 (Quantum flagship) and 101034929 (Fastera). This material is based upon work supported by the Air Force Office of Scientific Research under award number FA8655-23-1-7047. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the United States Air Force.

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Authors and Affiliations



F.H.L.K., H.A. and R.K.K. conceived the presented idea. H.A. fabricated the devices. H.A. and K.N. performed the mid-infrared measurements with inputs from R.K.K. and F.H.L.K. K.N. built the mid-infrared measurement setup with inputs from A.R.-P., R.K.K. and F.H.L.K. R.K.K, and H.A. performed terahertz far-field photocurrent measurements A.R.-P, R.K.K. and H.A. designed and built the measurement setup for terahertz photocurrent experiments. A.F., H.A. and G.S. performed low-temperature FTIR spectroscopy measurements. A.P., R.K.K. and F.H.L.K. developed the theoretical formalism and performed the analytical calculations. R.B. performed absorption calculations. K.W. and T.T. provided hBN crystals. H.A, P.P., L.V. and A.B. performed magnetotransport experiments. H.A., K.N. and R.K.K. analysed the results. R.K.K., H.A. and F.H.L.K. wrote the manuscript. R.K.K. and F.H.L.K. supervised the project. All authors provided critical feedback and helped shape the research, analysis and manuscript.

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Correspondence to R. Krishna Kumar or F. H. L. Koppens.

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Agarwal, H., Nowakowski, K., Forrer, A. et al. Ultra-broadband photoconductivity in twisted graphene heterostructures with large responsivity. Nat. Photon. 17, 1047–1053 (2023).

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