Temperature dependence of trapping and depth profiles of 6 to 15 kev deuterium in carbon

Abstract

Depth profiles of 30 keV D + 2 and 20 keV D + 2 implanted into edge and basal-oriented pyrolytic graphite have been measured by means of the D( 3He,α)H nuclear reaction in the temperature range of 300 to 800 K. At room temperature deuterium concentrations up to 30 at.% are found in a surface layer corresponding to the range of the ions. The measured depth profiles do not fully agree either with calculated range profiles or with the damage profiles, but are determined by the two together. At higher temperatures the deuterium concentrations decrease and the profiles broaden. At room temperature the amount of trapped deuterium increases linearly with dose below 10 18 deuterons/cm 2. The trapping coefficient is roughly 60%. At 5 × 10 18 deuterons/cm 2 the amount of trapped deuterium in the probed layer (~4000 Å) reaches saturation and the trapping coefficient becomes zero. The saturation value decreases with increasing temperature and increases with increasing energy.