An Approach to Nanoglasses through Anodic Oxidation of Sputtered Aluminum on Glass Surface

Abstract

The new processes for the preparation of nanoglasses have been developed through anodic oxidation. The aluminum thin film sputtered on the ITO thin film on the glass surface was decomposed into alumina by anodic oxidation technique. The alumina layer possessed nanometer size pore array standing on the glass surface. The sizes of the pore was widened by acid etching from 10-ý2nm to a few hundred nm. The glass substrate having the alumina nanostructures on the surface could transmit the UV and visible light at the wavelength range of 200 -800nm. The TiOŽ sol was impregnated into the pores of alumina layer and the sample was heated at -400 VC for 2 hr, converted into TiO 2 nanotubes of anatase phase. The acid etching could remove the alumina skeletons, leaving the TIQ 2 nanotube anray on the glass surface. These glasses were transparent to the light in LW-visible region. The electro deposition technique was applied to the introduction of Ni metal into pores, giving Ni nanorod aray on the glass surface. The glass samples possessing TiO 2 nanotube array showed very good catalytic function on the decomposition of acetaldehyde gas under the iradiation of UV light. The effect of the dimensions of the Ni nanornds on the magnetization was investigated. INTRODUCTIONThe anodic oxidation of aluminum has been used as the method to convert the aluminum surface into alumina for the improvement of the chemical durability. The anodic oxidation technique is knowa as the self organization process to generate the porous alumina where the nanopores are arranged as perpendicular to the substrate. Recently nanostroctured materials have attracted great interest for their potentiality leading to the unique functions in the optical properties, electronic properties, magnetic properties and mechanical properties. In these years, the porous anodic alumina has been studied to fabricate the nanostmctured materials [1][2][3][4][5]. The anodic oxidation of the thin aluminum film has been studied recently on the sputtered aluminum film on the Ta [6] and the Si [71 substrate, resulting in the oxidation of the aluminum layer followed by the oxidation of the substrate.The authors have been studying the formation of the nanostructures on glass surfaces and have developed the new process in which the sputtered alumina film on the conductive layer (tin-doped indium oxide (ITO)) on the glass substrate was converted into the nanostmcture~s by anodic oxidation [8]. The authors have also been studying the processes to introduce other compounds into nanopores of the anodic alumina using sol-gel technique and electro deposition. The TiO6 2 component could be introduced by sol-gel process [9,10] giving the high efficiency photo catalytic function [11]. The density of the nanopores of the alumina nanostroctures on the glass surface was estimated to be about 1000 Gbit/inch 2 and the introduction of the magnetic components possessing easy magnetization axis perpendicular to the substrate would be applicable to the ultra high density magnetic recording m...