利用钛保护层在ITO电极上直接制备大面积的超薄氧化铝膜

通过磁控溅射并引入钛保护层, 利用在0.3 mol·L^-1硫酸中20 V电压下二次阳极氧化, 在氧化铟锡(ITO)导电玻璃衬底上直接制备了超薄(约140 nm, 为阳极氧化前Al厚度的一半)、大面积(约4 cm²)的多孔阳极氧化铝(AAO). 扫描电子显微镜结果表明生成的微孔与衬底垂直, 孔径和孔间距分别约为30和60 nm. 我们发现钛保护层的作用是提高了Al层的附着性并且防止ITO被腐蚀, 在此体系中钛不能被其它的金属如铬、金、银或铜代替. 紫外-可见光谱透过率结果显示在阳极氧化过程中Ti被氧化成为透明的TiO₂, 利用10-20 nm的钛保护层以及二次阳极氧化过程, 能够保证高透明度. 在ITO上直接制备的这种透明、有序的AAO纳米结构在光子学、光伏领域和纳米制备等方面具有潜在应用.

Fabrication of Large Area of Anodic Aluminum Oxide Ultrathin Film Directly onto an ITO Electrode with a Ti Buffer Layer

Abstract: An anodic aluminum oxide (AAO) ultrathin film (-140 nm, about half the thickness of the original Al film) was successfully fabricated directly onto an indium tin oxide (ITO) electrode without the erosion of ITO by a two-step anodization process in 0.3 mol·L-1 H2SO4 solution at a constant voltage of 20 V. Here, a thin titanium buffer layer was included between the ITO electrode and the Al film by radio frequency (RF) magnetron sputtering. A large area (about 4 cm2) of porous alumina with nanoscaled channels perpendicular to the substrates was obtained. The average pore diameter and the pore interspace were approximately 30 and 60 nm, respectively. We found that the Ti buffer layer with a thickness of 10-40 nm between the Al layer and the ITO substrate played a critical role in improving the adhesion and ensuring ITO protection, which could not be duplicated by other metals, e.g., Cr, Au, Ag, and Cu. UV-visible transmittance spectra confirmed that the Ti buffer layer was oxidized and became transparent TiO2 and that 10-20 nm of the Ti buffer layer together with the two-step anodization process is suitable for high transparency. Therefore, the AAO specimen possessing a high nanoscale regularity and transparency may have potential use in photonics, photovoltaics, and nanofabrications.