Superlattice structures and Nb-doping in self-organized TiO2 nanotube layers: Controlled growth and electronic properties

近年来，自组织二氧化钛纳米管的电化学形成引起了人们的极大关注，因为这种结构具有很高的纳米级技术应用潜力。通常，这些纳米管是通过在稀释的HF电解液中对钛进行阳极氧化而形成的。在特定的电化学条件下，纳米多孔层由直径约为100 nm、相邻孔间距约150 nm的二氧化钛纳米管组成。我们实验室最近的实验表明，可以制造出相对较厚的二氧化钛纳米管(PM级)。本资金申请的一部分旨在详细调查自组织和毛孔生长过程中涉及的生长限制和机制。第二条途径将从光电化学性质的角度来探索二氧化钛纳米管的技术潜力。利用纳米管形式的二氧化钛的半导性用于太阳能转换和自清洁，需要详细研究纳米管在退火、掺杂和染料敏化时的性质。

Recently, the electrochemical formation of self-organized TiO2 nanotubes has attracted considerable attention due to the high potential of the structures for nanoscale based technological applications. Typically, these nanotubes are formed by anodization of Ti in diluted HF electrolytes. Under specific electrochemical conditions, nanoporous layers form that consist of TiO2 nanotubes with a diameter of approximately 100 nm and a spacing to neighboring pores of about 150 nm. Recent experiments in our laboratory demonstrate that comparably thick layers (pm-range) of TiO2 nanotubes can be produced. One part of the present funding application aims at a detailed investigation of the growth limits and mechanisms involved in the selforganization and pore growth processes. A second path will explore the technological potential of the TiO2 nanotubes in view of the photoelectrochemical properties. Exploiting the semiconductive nature of TiO2 in the form of nanotubes for e.g., solar energy conversion and self-cleaning requires detailed investigations on the properties of the tubes upon annealing, doping, and dye sensitization.