Direct nano-in-micropatterning of TiO2 thin layers and TiO2/Pt nanoelectrode arrays by deep X-ray lithography

Nano-in-micro-patterned heterogeneous substrates and Pt electrodes are prepared via organic/inorganic self-assembly combined with deep X-ray lithography. Nanoperforated titania membranes are obtained through dip coating from a sol-gel solution using block copolymer micelles as templating agent. Such thin films are selectively exposed to the X-ray radiation that leads to the structural local densification and permits the selective etching of the unexposed layer. Structural as well as electrochemical characterizations demonstrate that the final materials are micrometric features of a sub-10 nm thick perforated titania membrane that guarantees the accessibility to the substrate. This system was also applied to a conductive platinum-coated silicon surface to achieve micrometric features of nanoelectrode arrays. This scalable strategy of combining bottom-up and top-down approaches is thereby promising for various applications involving smart functional devices.