role of growth temperature in cvd synthesis of carbon nanotubes from ni-co bimetallic catalysts

the effect of temperature variation on the growth of carbon nanotubes (cnts) using thermal chemical vapor deposition (tcvd) is presented. nickel and cobalt (ni-co) thin films on silicon (si) substrates were used as catalysts in tcvd technique. acetylene gas was used in cnts growth process at the controlled temperature ranges from 850-1000 ̊ c. catalysts and cnts characterization was carried out using atomic force microscopy (afm), energy dispersive x-ray (edx), field emission scanning electron microscopy (fesem) and raman spectroscopy. it was found that the cnts diameters increased with the temperature. the cnts diameters were continually increased from 70 nm to 180 nm in the temperature range. in addition, the degree of crystallinity of the grown cnts decreased.