Fabrication of polycrystalline TiO₂ nanopatterns by TiO₂ sol base imprint lithography

This paper reports a process for fabricating TiO₂ nano-patterns using nanoimprint lithography and a sol-gel method. An ethanol-based TiO₂ sol was prepared using tetrabutylorthotitanate as a precursor and used as an imprint resin. A replicated polydimethylsiloxane (PDMS) mold was used as an imprint stamp. During the imprinting process at 5 atm and 200 °C for 1 h, the TiO₂ sol changed to a TiO₂ gel by absorbing the solvent into the PDMS mold. After imprinting, a TiO₂ gel pattern was formed on an oxidized Si wafer. After subsequent annealing, it confirmed that patterns of the master template were transferred to TiO₂ patterns by Scanning Electron Microscopy. Furthermore, Transmission Electron Microscopy and X-Ray Diffraction showed that the TiO₂ gel patterns had been converted to an inorganic polycrystalline TiO₂ pattern.