Synthesis of anodic aluminum oxide (AAO) at relatively high temperatures. Study of the influence of anodization conditions on the alumina structural features

Anodic aluminum oxide (AAO) is a well known template for nanofabrication. Structural features of AAO like pore diameter, interpore distance, porosity, pore density can be fully controlled by operating conditions of anodization. Typically, self-organized two-step anodization is carried out at low temperature (below room temperature) and is a time consuming process. There are individual experiments describing anodization at temperatures close to room temperature. In our study, furthermore, a systematic analysis of the anodization condition influence on the nanoporous alumina structural features was done. The anodization temperature was ranging from 35 to 50 degrees C increasing significantly current density of the processes, which has increased oxide film growth rate. The anodizing potential ranged from 20 to 60 V and time of the anodization steps was 30, 60 or 120 min. The data obtained has shown that the pore diameter increases with potential, temperature and time of anodization, while the interpore distance is influenced solely by the potential. Temperature and time changes do not affect the interpore distance. Porosity is also influenced by potential, temperature and duration of anodization. Pore density is influenced only by the potential. The synthesis of AAO reported here gives possibilities to obtain the AAO templates in a faster and cheaper way, essential for researchers applying anodic alumina as a template. (C) 2011 Elsevier B.V. All rights reserved.