Investigation for conductance behavior of single walled carbon nanotubes decorated with UNCD and graphitic spherules using STM/STS

Carbon nanostructures were grown on single walled carbon nanotubes (SWCNTs) using hot filament chemical vapor deposition under diverse growth conditions. The difference in the morphological and structural properties of these deposits was confirmed mainly using transmission electron microscopy. These results depict the growth/decoration of ultrananocrystalline diamond (UNCD) and graphitic spherules i.e. dissimilar carbon phases onto the tube surface, further confirmed by estimating the ratio of sp2/sp3 carbon using X-ray photoelectron spectroscopy. The electronic properties of individual CNTs decorated with UNCD and graphitic spherules were investigated using scanning tunneling spectroscopy technique. Semiconducting behavior and the metallic behavior observed for the tubes decorated with UNCD and graphitic spherules respectively demonstrate the possibility to use these composites for various applications depending on the requirements