The behaviour of 1D CuI crystal@SWNT nanocomposite under electron irradiation

Nanocomposite 1D CuI crystal@SWNT was obtained by the growth of CuI nanocrystals inside single walled carbon nanotubes (SWNTs) using the capillary technique. High resolution transmission electron microscopy (HRTEM) investigation of the atomic structure of 1D CuI crystals revealed two types of 1D CuI crystals: with growth direction < 001 > and < 1(1)over-bar0>> relative to the bulk hexagonal CuI stucture. EM images were recorded and atomic models of the structure were proposed. According to the proposed models and image simulations, the main contrast in the 1D crystal images arises from the iodine atoms. In this paper the 1D CuI crystal@SWNT nanocomposite behavior determined mainly by the influence of the electron beam was investigated and it is shown that the 1D CuI nanocrystals can oscillate and rotate inside the nanotube channel under a 100kV electron beam. The oscillations occur within an exposure time of 25 s. With longer exposure time of similar to 90 s, the 1D crystal gradually decreases in length, sometimes moving inside the SWNT, Cut begins to evaporate and extruded, probably through defects in the tube wall. Outside the tube iodine is gradually lost but copper atoms are condensed into faceted clusters which grow subsequently into 3D CuI nanocrystals with fcc lattice

Double-walled carbon nanotubes fabricated by a hydrogen arc discharge method

Double walled carbon nanotubes (DWNTs) were obtained by the arc discharge technique in an atmosphere of Ar and H2 mixture (1:1/v:v) at 350 Torr. The catalyst was prepared from a mixture of Ni, Co, Fe and S powders heated in an inert gas atmosphere at 500°C for 1 h. High resolution electron microscopy (HREM) revealed that the dominant type of obtained nanotubes were DWNTs with outer diameter in the range of 1.9-5 nm and inner tube diameters in the range 1.1-4.2 nm. As a rule, the DWNT tubes form into bundles. Occasionally single walled nanotubes (SWNTs) were observed by HREM although Raman spectroscopy did not reveal the presence of significant quantities of these tubules in the bulk product. © 2001 Elsevier Science Ltd