Graphene nanoribbons are of potential use in the development of electronic and optoelectronic devices. However, the preparation of narrow and long nanoribbons with smooth edges, sizeable bandgaps and high mobilities is challenging. Here we show that sub-10-nm-wide semiconducting graphene nanoribbons with atomically smooth closed edges can be produced by squashing carbon nanotubes using a high-pressure and thermal treatment. With this approach, nanoribbons as narrow as 1.4 nm can be created, and up to 54% of single- and double-walled nanotubes in a sample can be converted into edge-closed nanoribbons. We also fabricate edge-opened nanoribbons using nitric acid as the oxidant to selectively etch the edges of the squashed nanotubes under high pressure. A field-effect transistor fabricated using a 2.8-nm-wide edge-closed nanoribbon exhibits an on/off current ratio of more than 104, from which a bandgap of around 494 meV is estimated. The device also exhibits a field-effect mobility of 2,443 cm2 V−1 s−1 and an on-state channel conductivity of 7.42 mS.
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C.C. acknowledges support from the National Natural Science Foundation of China for Excellent Young Scholars (no. 61622404), Chang Jiang (Cheung Kong) Scholars Program of Ministry of Education of China (no. Q2017081), National Natural Science Foundation of China (no. 62074098) and Science and Technology Innovation Action Program from the Science and Technology Commission of Shanghai Municipality (no. 15520720200). Y.L., W.L.M. and the high-pressure DAC experiments were supported by the United States Department of Energy through the Stanford Institute for Materials and Energy Sciences DE-AC02-76SF00515. Work by J.N.W. was supported by the National Key R&D Program of China (2018YFA0208404) and Innovation Program of Shanghai Municipal Education Commission. J.G. was supported by NSF grant nos. 1809770 and 1904580. Work at ORNL was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. W.Z. acknowledges support from the Beijing Outstanding Young Scientist Program (BJJWZYJH01201914430039).
The authors declare no competing interests.
Peer review information Nature Electronics thanks Antonio Pantano, Chee-Tat Toh and An-Ping Li for their contribution to the peer review of this work.
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Chen, C., Lin, Y., Zhou, W. et al. Sub-10-nm graphene nanoribbons with atomically smooth edges from squashed carbon nanotubes. Nat Electron 4, 653–663 (2021). https://doi.org/10.1038/s41928-021-00633-6
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