High-Resolution Scanning Near-Field Optical Lithography of Conjugated Polymers

Authors

  • Daniel Credgington,

    1. Department of Physics and Astronomy (CMMP Group) and, London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT (UK)
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  • Oliver Fenwick,

    1. Department of Physics and Astronomy (CMMP Group) and, London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT (UK)
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  • Ana Charas,

    1. Department of Physics and Astronomy (CMMP Group) and, London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT (UK)
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  • Jorge Morgado,

    1. Instituto de Telecomunicações, Instituto Superior Técnico, Avenida Rovisco Pais, P-1049–001, Lisboa (Portugal)
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  • Klaus Suhling,

    1. Department of Physics, King’s College London, The Strand, London WC2R 2LS (UK)
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  • Franco Cacialli

    Corresponding author
    1. Department of Physics and Astronomy (CMMP Group) and, London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT (UK)
    • Department of Physics and Astronomy (CMMP Group) and, London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT (UK).
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Abstract

The fabrication of high-resolution nanostructures in both poly(p-phenylene vinylene), PPV, and a crosslinkable derivative of poly(9,9′-dioctylfluorene), F8, using scanning near-field optical lithography, is reported. The ability to draw complex, reproducible structures with 65000 pixels and lateral resolution below 60 nm (< λ/5) is demonstrated over areas up to 20 μm × 20 μm. Patterning on length-scales of this order is desirable for realizing applications both in organic nanoelectronics and nanophotonics. The technique is based on the site-selective insolubilization of a precursor polymer under exposure to the confined optical field present at the tip of an apertured near-field optical fiber probe. In the case of PPV, a leaving-group reaction is utilized to achieve insolubilization, whereas the polyfluorene is insolubilized using a photoacid initiator to create a crosslinked network in situ. For PPV, resolubilization of the features is observed at high exposure energies. This is not seen for the crosslinked F8 derivative, r-F8Ox, allowing us to pattern structures up to 200 nm in height.

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