Spectroscopic investigation on carbon nanotubes coated with ZnO nanoparticles

ZnO nanoparticles were successfully coated on the surface of carbon nanotubes (CNTs) during the final stage of the growth process of CNTs using radio-frequency plasma enhanced chemical vapour deposition. During the coating process, Zn or ZnO particles with oxygen vacancies can be selectively anchored to the oxygen atom of the oxygen-containing groups on the surface of CNTs and can be perfectly oxidized by active oxygen atoms in the annealing process. The appropriate amount of coated nanoparticles effectively reduces the formation of various structural defects induced by oxygen or hydrogen atoms on the surface of the CNT wall, which can be evaluated through a decrease in the intensity ratio of disorder graphitic band (D peak) over graphitic C-C stretching band (G peak) in the Raman spectrum as well as a distinct decrease in the intensity peak, corresponding to C-H stretching vibration, in the infrared spectrum.