Imaging helical potassium hexaniobate nanotubes

Potassium hexaniobate nanotubes have been synthesized at room temperature and characterized by high-resolution transmission electron microscopy (HRTEM) and energy-dispersive x-ray analysis. It is shown that HRTEM images may be used effectively to determine the helicity of the nanotubes, and, in particular, it is found that almost all nanotubes have their axes pointing within a few degrees from the [100] direction of the K4Nb6O17 structure. (C) 2003 American Institute of Physics.