High-Resolution Scanning Near-Field Optical Lithography of Conjugated Polymers
; Fenwick, O.
; Suhling, K.
; Cacialli, F.
Advanced Functional Materials Vol. 20, Nº 17, pp. 2842 - 2847, September, 2010.
ISSN (print): 1616-301X
Journal Impact Factor: 6,808 (in 2008)
Digital Object Identifier: 10.1002/adfm.201000202
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-fi eld 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 μ m × 20 μ m. 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 confi ned optical fi eld present at the tip of an apertured near-fi eld optical fiber probe. In the case of PPV, a leaving-group reaction is utilized to achieve insolubilization, whereas the polyfl uorene 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 F8derivative, r-F8Ox, allowing us to pattern structures up to 200 nm in height.