Silica nanotube arrays have been fabricated from vertical silicon nanowire templates prepared by Vapor-Liquid-Solid (VLS) epitaxial growth. The silicon nonowire arrays are uniformly oxidized by a dry oxidation process in a tube furnace heated to 1000 °C and filled with pure O2, which gives SiO2 sheaths with continuous silicon wire cores inside. A dry etch process with XeF2 as etchant removes the silicon cores, thus silica nanotube arrays are obtained. The resulting silica nanotubes are more than 10 μm long with an inner diameter range from 10 to 200 nm. A nonofluidic device has been fabricated based on individual silica nanotubes. The nanotube is drop-casted onto a silica substrate from a solution and after the solution is dried out, a 200 nm thick chrome layer is sputter deposited. A 3 μm wide Cr gate structure is patterned across the silica nanotube. Photoresist is patterned to define the hydrophilic (silica) and hydrophobic (photoresist) regions. The hydrophilic regions form a reservoir at each side of the nanotube, thus giving us a nanofluidic device. Ion current flow through the nanotube has been measured in 1 M KCl solution and the measured current matches the theoretical estimation reasonably well.

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