The influence of aluminum grain size on alumina nanoporous structure

Abstract

An approach to control the interpore distances and nanopore diameters of 150-nm-thick thin aluminum films is reported here. The Al thin films were grown by sputtering on p-type silicon substrate and anodized with a conventional anodization process in a phosphoric acid solution. It was found that interpore distance and pore diameter are related to the aluminum grain size and can be controlled by annealing. The grain contours limit the sizes of alumina cells. This mechanism is valid for grain sizes supporting only one alumina cell and consequently only one pore.

Formation of Nanoporous Anodic Alumina by Anodization of Aluminum Films on Glass Substrates

“…There are many reports on studying the formation of PAA from deposited Al films on glass [ 11 , 14 – 19 ]. Analysis of published data shows that during the formation of PAA from aluminum film on any substrate, not only the process of anodic oxidation affects the outcome but also the way of deposition of aluminum films [ 20 ], the impurity in the film [ 21 ], the heat treatment of aluminum film [ 22 ], the thickness of Al film [ 23 ], and the presence of a conductive underlayer on an insulating substrate [ 17 , 18 ].…”

Duplex nanoporous alumina and polyelectrolyte adsorption: more insights from a combined neutron reflectivity and electron microscopy study

“…To perform NR on nAAO, a low roughness and strong adhesion of the sample on the substrate, such as Si wafer, is required . As previously observed, Al anodization on Si wafers exhibits different structural characteristics than the anodized aluminum foils and greatly depends on the sputtered Al film morphology tuned by the sputtering conditions 20 . Here duplex nAAO have been synthesized through an anodization/etching/anodization sequence.…”

Influence of wet etching time cycles on morphology features of thin porous Anodic Aluminum oxide (AAO) template for nanostructure’s synthesis

“…Different processes must be performed to produce highly ordered thin porous AAO template, comprising heat treatment, second-step of anodization and pore widening. After heat treatment, the defects were released (relaxation of structural and microstructural defects as well as imperfections), resulting in the increase of grain size and root mean square roughness of the Al thin film, which is reflected by the ordering observed within porous AAO template [15,16]. The second-step of anodization involves the striping (first anodizing step) of the first aluminum oxide layer, which is less ordered.…”