Noticing that there are nearly no defects in the regions where the depth exceed 1.4 lm, this is consistent with the SRIM calculations. The enlarged image indicates that the black spots were some dislocation loops, range in the diameter size from 3 to 10 nm (Fig. 2(c)).
As the ion dose increased from 0.62 to 3.7 dpa (Fig. 2(d) and (e)),