Towards ideal hexagonal self-ordering of TiO2 nanotubes

The present work reports on key factors that influence the degree of order in anodic TiO2 nanotube layers. We show that the anodization voltage and the Ti purity are of crucial importance for the ideality of self-organization within the nanotube layers and that repeated anodization can significantly improve hexagonal ordering. Optimizing each factor significantly reduces the variation in the average pore diameter and strongly reduces the areal density of polygon ordering/packing errors. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.