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In this study, multi-walled carbon nanotubes (MWNTs) were synthesized in high yield in the presence of zinc-oxide (ZnO) nanorods catalyst by thermal chemical vapor deposition for the fast time.The ZnO nanorods prepared on silicon substrates by hydrothermal process act as catalyst for the growth of carbon nanotubes (CNTs).It is found that CNTs can be synthesized on ZnO nanorods catalyst using thermal chemical vapor deposition at 900 C in an ambient of methane and argon mixed gas.Carbon nanotubes grown on ZnO catalyst nanorods were characterized by electron scanning microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy.Elemental analysis was conducted using x-ray dispersive spectrometer (EDS).Our research results reveal that the carbon nanotubes grown on ZnO nanorods showed a multi-walled structure with defective graphite sheets at the wall.The SEM images and TEM imaged showed that CNTs were quite uniform and disordered.Raman spectra show that there is larger crystallinity or little amorphous carbon than those grown on ZnO nanorods.EDS results reveal that the CNTs grown on ZnO nanorods do not need any purification process to optimize the field emission characteristics of the CNTs.The Fowler-Nordheim plot showed a good linear fit, indicating that the emission current of carbon nanotubes follows Fowler-Nordheim behavior.