From Nanowires to Nanotubes

Steps in producing nanotubes from nanowires (a). A transmission electron microscope allows us to see how spinel nanotubes are created after thermally treating ZnO-Al2O3 core-shell-nanowires (b, c). Most of the one-dimensional nanostructures produced are hollow over the entire length of the previous nanowire. The researchers created free-standing nanotubes, 20 micrometres long, with a diameter of 30 to 40 nanometres and walls 10 nanometres thick. These nanotubes feature excellent crystallinity and uniformity. The results show how the Kirkendall effect can be used generally to produce all kinds of hollow nano-objects. Image: Max Plank Institute for Microstructure Physics