Deposition of diamond and diamond-like carbon nuclei by electrolysis of alcohol solutions

We show that nuclei and aggregates of diamond, diamond-like carbon (DLC) and crystalline graphite may be deposited by the electrolysis of heated methanol. The structures were characterized by micro-Raman spectroscopy, optical microscopy and scanning electron microscopy (SEM). It is observed that bubble formation inhibits the film deposition in DLC form on the immersed substrate but enhances the formation of carbon nuclei on the wetted capillary area of the substrate. We observed experimentally an inhomogeneity in the film thickness in the vertical direction and explain this effect by relating it to an inhomogeneous turbulent 'boiling layer' present near the cathode. In addition, we observed that the film growth rate on the wetted capillary area is much higher than the average growth rate on the immersed cathode. (C) 1999 Elsevier Science B.V. All rights reserved.