TEM investigation of nanostructures with a high aspect ratio

Abstract

In this work, we intend to demonstrate an essential role that can play a TEM investigation of cross-sections of HAR nanostructures for a characterization of their internal structure and surface morphology. For illustrative purposes we briefly present some results of the TEM investigation of CuO, GaAs, GaN whiskers as well the comparative study of mineral and synthetic chrysotile nanotubes. In particular, the investigation of CuO nanowires (NWs) revealed that they do not have a proper crystal habit and in a majority of cases the nanowhiskers have a bi-crystalline structure, but rarely come across ones consisting of more than two crystals. And it is also interesting, that a boundary of a junction of two crystals can be not planar. As a result of the analysis of diffraction patterns of cross-sections of different nanowhiskers the growth direction was determined as [110]. Concerning the GaAs and GaN whiskers, their cross-sections have the shape close to a regular hexagon, as was expected. In addition, the observed GaN whisker has the faceted nanopipe, also with a hexagon shape. The average diameter of nanotubes in a chrysotile fibre was estimated and compared with the diameters of the given synthetic chrysotile nanotubes.