Surface properties and electrochemical characteristics of carbon materials modified by ion implantation

Zn+, Cd+, Ti+, and Ar+ have been implanted into carbon for the surface modification. The doses of ions were 1016 - 1017 ions cm-2 at an energy of 150 keV. In the case of diamond, distribution of the implanted element in the surface layer showed Gaussian-like distribution predicted by LSS range theory. An amorphous layer of twice thickness of the average projected range was formed by the ion beem bomberdment. Rutherford backscattering spectroscopy has been employed for these structural analysis. The amorphous surface layer shows high electrical conductivity, which is useful for inhibition of electrification of a diamond tool and a needle for disk-record. The concentration-depth profiles of the implanted element in glassy carbon substrates are also able to be predicted from the range theory, which was found from the results of a secondary ion mass spectroscopy. The zinc and titanium in the surface layer were defined as ZnO and TiO2, respectivery, by a X-ray photoelectron spectroscopy. The amorphization of GC surface with ion implantation was found by a laser Raman spectroscopy. The electrochemical reactivity of ion-implanted elements in GC electrode surface has been investigated by means of a voltammetry. No oxidation and reduction of the elements were observed on the voltammograms. The electrode characteristics of ion-implanted GC have been evaluated from voltammetric behavior of the electrodes. The ion-implanted GC electrodes showed low residual current, high hydrogen overpotentials (except for Ti-implanted GC), and similar reactivities of redox reaction of [Fe(CN)6]sup(3+/4+). These characteristics are useful for electroanalytical purpose of the electrodes. (author)