Correlation between annealing effects of damage and implanted deuterium release from graphite

In the present study the correlation between annealing effects of damage and release of implanted deuterium into graphite was investigated through the behavior of deuterium in the graphite during D2+ implantation. From the results of TDS experiments, the thermalized deuterium participated to form trapping sites. However the energetic deuterium would directly form CDx−1 (x=2, 3, and 4) and simultaneously its kinetic energy was transferred to carbon atoms, and then this resulted in changing the electronic state of carbon from the sp2 state to the sp3 state. Those processes dominated during D2+ implantation at lower temperatures below 573 K. On the other hand, at higher implantation temperatures above 573 K, the disordered structure of the graphite was recovered to a crystalline graphite structure and then deuterium release was started. The effects of heating the sample, known as thermal annealing effects, were correlated with the hydrogen release from the graphite.