Optical and structural studies of copper nanoparticles and microfibers produced by using carbon nanotube as templates

Abstract

Copper nanoparticles and microfibers have been prepared by solid state reaction using carbon nanotube (CNT) as a template. Their optical and structural properties were investigated by scanning and transmission electron microscopy, X-ray diffraction (XRD), Raman scattering, and photoluminescence. Carbon nanotube template was found to be the main contributor to the Raman spectra, however, after the introduction of copper, we found the G band shifted to higher frequency by a few wavenumbers. The shift was found to also relate to the ratio of copper to carbon nanotube. With copper form change from nanoparticles to microfiber, the ratio of scattering intensity between D band and G band of carbon nanotube increases, which reveals a change in microcrystallinity. Compared with pure carbon nanotube, a broad photoluminescence background was found to be superimposed on the Raman spectrum of these copper related carbon nanotube, and the intensity of this photoluminescence background also increased with respect to the ratio of copper to carbon nanotube. High resolution X-ray diffraction indicated that the copper lattice constant of copper fibers decreased with respect to its bulk form.