Effect of sequential Fe²⁺ − C⁺ implantation on deuterium retention in W

Deuterium (D) retention behavior for the sequential 6 MeV iron (Fe) and 10 keV carbon (C) implanted tungsten (W) were evaluated by thermal desorption spectroscopy (TDS) and β-ray-induced X-ray spectroscopy (BIXS) to understand the synergetic effect of defect formation and C existence on D retention behavior for W under various damage distribution profiles. The experimental results indicated that retention of D trapped by dislocation loops was controlled by 10 keV C⁺ implantation. The D retention was reduced in the sequential Fe²⁺ − C⁺ implanted W with higher C⁺ fluence in comparison to that with lower C⁺ fluence due to the formation of C-W layer which suppressed D diffusion toward the bulk and dense defects at the surface which reduce effective D diffusion coefficient. On the other hand, the amount of D trapped by the defects in the deeper region than C⁺ implantation region (50 nm) was increased due to the formation of dense defects by 6 MeV Fe²⁺ implantation within the depth of 1.5 μm.