Nano-scale lithography and microscopy of organic semiconductors

• Main Author: Credgington, D. J. N.
• Published: University College London (University of London) 2010
• Subjects: 500
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.565098

The development of organic electronic and photonic devices increasingly requires the development of micro- and nano-structured morphologies, which in turn require the development of both prototyping and scalable patterning methods. This thesis presents investigations which explore and develop unconventional patterning techniques for a variety of conjugated polymers and organic molecules, using scanning near-field optical lithography (SNOL), scanning thermal lithography (SThL) and molecular self-assembly. Optimised formation of organic nanostructures is demonstrated, at resolutions which equal or better the current state of the art, with patterning resolution for isolated structures below 60nm for SNOL and 30nm for SThL. SThL in particular is demonstrated as a technique which can achieve serial write-speeds of over 100 μm/s, with significant potential for up-scaling. Furthermore, arbitrarily defined two-dimensional large-area nanostructures up to 20 × 20 μm are demonstrated using SNOL while maintaining both high resolution and the integrity of the probe. The nanostructures fabricated in the course of this work, and others, are characterised using both optical and topographic techniques, primarily atomic force microscopy and near-field microscopy. The detailed formation mechanisms for structures fabricated using SNOL via an in-situ conversion route are systematically investigated and contrasted with other formation routes, resulting in a comprehensive account of the factors affecting structure morphology. In addition, the optimised nanostructures achieved in this work are shown, within this context, to be very close to best achievable with an apertured scanning near-field system.