Radiation damages and bubble formation of ion implanted furan-resin-derived carbon

Furan-resin-derived carbon generally produces a glass-like carbon (GC) having entangled graphene layers after high temperature heat treatments. However, furan-resin-derived carbon produced well-graphitized thin skin on surfaces after heat-treatment at 3000 °C. ion implantation is a useful technique for surface modification, we used them to investigate the mechanism of well-graphitized thin skin on surfaces of furan-resin-derived carbon after heat-treatment at 3000 °C. s investigation, we observed morphological changes on Ar+ or Xe+ implanted GC surfaces using SEM&TEM and Raman spectroscopy. Xe ions were implanted into the furan-resin-derived carbon heat-treated at 3000 °C at energy of 60–160 keV at a fluence ranging from 1×1015 to 1×1017 ions/cm2. Microstructural changes were examined by Raman spectroscopy. The implanted surfaces of the specimens were changed to an amorphous structure by the ion implantation. Moreover, morphological SEM&TEM observations revealed that clear bubbles with diameter of 10–80 nm were present in the Ar+-implanted specimen at a fluence of 1×1017 ions/cm2. However, bubbles did not appear in the Ar+-implanted specimen at a fluence of 1×1016 ions/cm2. On the other hand, bubbles with diameter of 15–30 nm were present in the Xe+-implanted specimens at a fluence of 1×1016 ions/cm2. +-implanted specimens were subjected to annealing of re-heat-treatment at 3000 °C. After the annealing, the bubbles were lost in the interior of specimens by cross-sectional SEM observations. Moreover, on the implanted surfaces appeared big bubbles, which were not presented on the implanted surface before annealing. The sizes of these big bubbles were about 2–10 μm. Using Raman spectroscopy, we observed that on the surface of the big bubbles the structure was re-well-graphitized. On the surface of non-bubbled areas it was less graphitized. Thus annealing provided a restoration of the structural, but much effective only on the bubble surfaces.