The structure of copper-doped amorphous hydrogenated carbon films

A study of the nanostructure of a-C:H:Cu films by x-ray small-angle scattering, x-ray diffraction, TEM, and visible and UV spectroscopy is reported. It has been established that introduction of 9–16 at.% Cu not only decorates the original carbon fragments but produces extended (up to 4 µm in length) formations of copper-decorated strongly elongated ellipses as well. At 14–16 at.% Cu, these linear clusters represent copper nanotubes with a core made up of the original ellipses drawn in a line. It is these conducting copper formations that account primarily for the strong increase in conductivity at 12–16 at.% Cu contents in a-C:H films.