Molecular Switch for Sub-Diffraction Laser Lithography by Photoenol Intermediate-State Cis-Trans Isomerization
| Autor: | Gerd Ulrich Nienhaus, Lu Zhou, Christopher Barner-Kowollik, Joachim E. Fischer, Markus M. Zieger, Patrick Mueller, Martin Wegener, Benjamin Richter, Alexander S. Quick, Martin Bastmeyer, Jonathan B. Mueller |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Population General Physics and Astronomy 02 engineering and technology 010402 general chemistry 01 natural sciences law.invention Optics law General Materials Science education Lithography Molecular switch education.field_of_study business.industry General Engineering STED microscopy 021001 nanoscience & nanotechnology Laser Cis trans isomerization 0104 chemical sciences Optoelectronics Photolithography 0210 nano-technology business Maskless lithography |
| Zdroj: | ACS nano. 11(6) |
| ISSN: | 1936-086X |
| Popis: | Recent developments in stimulated-emission depletion (STED) microscopy have led to a step change in the achievable resolution and allowed breaking the diffraction limit by large factors. The core principle is based on a reversible molecular switch, allowing for light-triggered activation and deactivation in combination with a laser focus that incorporates a point or line of zero intensity. In the past years, the concept has been transferred from microscopy to maskless laser lithography, namely direct laser writing (DLW), in order to overcome the diffraction limit for optical lithography. Herein, we propose and experimentally introduce a system that realizes such a molecular switch for lithography. Specifically, the population of intermediate-state photoenol isomers of α-methyl benzaldehydes generated by two-photon absorption at 700 nm fundamental wavelength can be reversibly depleted by simultaneous irradiation at 440 nm, suppressing the subsequent Diels-Alder cycloaddition reaction which constitutes the chemical core of the writing process. We demonstrate the potential of the proposed mechanism for STED-inspired DLW by covalently functionalizing the surface of glass substrates via the photoenol-driven STED-inspired process exploiting reversible photoenol activation with a polymerization initiator. Subsequently, macromolecules are grown from the functionalized areas and the spatially coded glass slides are characterized by atomic-force microscopy. Our approach allows lines with a full-width-at-half-maximum of down to 60 nm and line gratings with a lateral resolution of 100 nm to be written, both surpassing the diffraction limit. |
| Databáze: | OpenAIRE |
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