Formation of TiO2 nanopattern using reverse imprinting and sol-gel method

Abstract

TiO2 and its nanopattern fabrication have been studied intensively because of its wide band gap and photocatalystic nature. TiO2 nanopatterns can be made by conventional patterning techniques, consisting of deposition, photolithography, and etching processes. However, these processes include complicated and expensive process steps, such as photolithography. Therefore, a simpler and more economic process is needed. In this work, TiO2 nanopatterns were fabricated using reverse-imprint lithography and the sol-gel method. Ethanol based TiO2 sol was prepared using tetrabuthylorthotitanate (C16H36O4Ti) and diethanolamine (C4H11NO2). TiO2 sol was then coated on the surface of the replicated polymer mold of hard-polydimethylsiloxane and polydimethylsiloxane by spin coating and transferred to the substrate by the reverse imprinting process at 200 degrees C. A postimprint annealing process was subsequently carried out to form the TiO2 polycrystalline phase. The x-ray diffraction and x-ray photoelectron spectroscopy results confirmed that the transferred TiO2 nanopattern was chemically pure polycrystalline TiO2.