The regularities of high-fluence ion-induced graphitization of diamond

The process of high-fluence ion-induced graphitization and the influence of irradiation by 10-30 keV Ar+, Ne+, N+, N2+ and C+ ions at temperatures from 30 to 720 °C on the conductivity and microstructure of polycrystalline diamond surface layer were experimentally studied. The increase of diamond temperature during irradiation leads to the ion-induced graphitization at Тir > Tgr ≈ 200 °C. It has been found that Tgr practically coincides with the corresponding temperatures of dynamic annealing of radiation damage in graphite. The Raman spectra indicate that irradiation with neon and argon ions at temperatures of the diamond more than Tir > 500 °C leads to the formation of nanocrystalline graphite layer that increases resistivity of the irradiated layer. This effect is not observed under irradiation by nitrogen ions. As for C+ ion irradiation the synthesis of diamond with a thin graphite-like layer formation on the surface has been observed.