Abstract
We demonstrate a different approach to direct nanoimprint lithography of oxides, in particular TiO2, using the metal methacrylate route which not only gives very high resolution (similar to 20 nm) but also provides yields of similar to 100% over areas > 1 cm x 1 cm. TiO2 was imprinted using a polymerizable liquid 'TiO2 resin' consisting of a mixture of titanium methacrylate, ethylene glycol dimethacrylate, and azobis-(isobutyronitrile). The resin underwent free radical polymerization when imprinted using a silicon mold at 110 degrees C with pressures as low as 10 bar. Polymerization strengthens the imprinted structures, thereby giving similar to 100% yield after demolding. Heat-treatment of the imprinted structures at 400 degrees C resulted in the loss of organics and their subsequent shrinkage (similar to 75%) without the loss of integrity or aspect ratio, and converted them to TiO2 nanostructures as small as similar to 20 nm wide. Furthermore, our method demonstrates that large imprinted areas of sub-100-nm features can be achieved by sub-micron molds which translate into huge cost savings with the added flexibility of direct patterning of unary as well as multi-component oxides.