Nanostructure characterization of tungsten-containing nanorods deposited by electron-beam-induced chemical vapour decomposition

Electron-beam-induced chemical vapour decomposition was performed in a scanning transmission electron microscope using a precursor of tungsten carbonyl (W(CO)6). The self-supporting nanorods were grown from the edges of a C film with widths that depend on the electron-beam scanning speed used in the fabrication process. The nanostructure of as-deposited nanorods has been characterized in detail using energy-dispersive X-ray spectroscopy, selected-area electron diffraction, microdiffraction and high-resolution transmission electron microscopy. A mixture of nanocrystallites and amorphous phases was observed for all beam scanning speeds used for deposition. High-resolution transmission electron microscopy demonstrated that the size of nanocrystallites in as-deposited nanorods ranges between 1.5 and 2.0 nm. The direct evidence of the presence of pure W nanocrystallites in as-deposited nanorods was revealed by microdiffraction.