Deuterium implantation in graphite

A study has been made of deuterium ion implantation in polycrystalline graphite over the temperature range 100 K to 450 K. Deuterium depth profiles are obtained using a method based on observing the energy spectra of the tritons and protons from D-D reactions initiated with a 200 keV probing deuteron beam. In marked contrast to the low adsorption for gaseous hydrogen previously reported, graphite is found here to retain large concentrations of implanted deuterium with atomic loadings exceeding unity in the deeper regions of a cold target. The amount of deuterium retained continues to decrease with increasing temperature until at 150°C the retention has fallen to approximately half that at −160°C. No evidence is found for a layer of surface deuterium of the type seen in metals such as copper. Scanning electron micrographs of irradiated areas show no observable surface deformation for doses of up to 2.4 × 10¹⁹ deuterons/cm².