Figure 3

The number of surviving point defects in the bulk region of Cu–Gr/R0 versus the number of cascades.
The green box and red circle represent the numbers of interstitials and vacancies in the bulk region, respectively. The number of the vacancies of Cu/R0 is also shown as the blue triangle, while the number of the interstitials of Cu/R0 does not appear due to the equivalence between the interstitials and vacancies in the Cu/R0.