Transfer Molding of Nanoscale Oxides Using Water-Soluble Templates

Abstract

We report a facile method for creating nanoscopic oxide structures over large areas that is capable of producing high aspect ratio nanoscale structures with feature sizes below 50 nm. A variety of nanostructured oxides including TiO(2), SnO(2) and organosilicates are formed using sol-gel and nanoparticle precursors by way of molding with water-soluble polymeric templates generated from silicon masters. Sequential stacking techniques are developed that generate unique 3-dimensional nanostructures with combinatorially mixed geometries, scales, and materials. Applicable to a variety of substrates, this scalable method allows access to a broad range of new thin film morphologies for applications in devices, catalysts, and functional surface coatings.

Fabrication, electrical and optical properties of silver, indium tin oxide (ITO), and indium zinc oxide (IZO) nanostructure arrays

“…Over the last decade a variety of methods have been reported for fabrication of 1D nanostructured metals and metal oxides [28][29][30][31][32][33][34][35][36][37]. Along with the oblique incidence deposition technique [28] and traditional photolithography [29] bottoms up approaches such as solution phase and hydrothermal growth of crystalline rods [30,31], oxidation [32] or anodization of metal foils [33], and vapor phase growth of titania nanostructures [34,35] have been reported.…”

“…Patterning of oxides with sub-500 nm structures has been demonstrated using PDMS and perfluoropolyether based soft lithography [36]. Recently a transfer molding approach for the fabrication of large area nanostructured oxides including TiO 2 , SnO 2 and organosilicates has also been reported [37]. In contrast to these strategies, the creation of various metal and transparent conducting oxide (TCOs) nanopatterns using a high aspect ratio thermally stable polymer nanostructure as a common scaffold holds a number of inherent advantages.…”

Electrowetting Assisted Air Detrapping in Transfer Micromolding for Difficult-to-Mold Microstructures

“…29,30 For instance, a mold made of a water-soluble polymer (poly(vinyl alcohol) or PVA), which has a good wettability for a kind of titania precursor solution, was well filled when the solution was spinned on the PVA mold. 33 On the contrary, for a mold with a dewetting or hydrophobic property, a certain volume of air tends to be trapped because the advancing threephase contact line cannot continuously pass throughout the sidewall and bottom of a cavity before the liquid touches the next edge of the cavity. 31,32 Such an air-trapping phenomenon can be explained by the well-known Cassie-state dewetting.…”

Nanotransfer Printing with sub‐10 nm Resolution Realized using Directed Self‐Assembly

“…The advantages of these techniques include simplicity, versatility, moderate resolution, low cost, and high throughput, which provide opportunities to readily fabricate various devices such as transistors, sensors, microfluidic devices, and so on 10. Among these methods, nanotransfer printing (nTP) has shown great potential for conveniently generating various functional inorganic nanostructures such as gold, TiO 2 , SnO 2 , ZnO, and so on 11–14…”