H+, N+, and Ar+ ion irradiation induced structure changes of carbon nanostructures

The effects of H+, N+, and Ar+ ion irradiation on structural changes in multi-walled carbon nanotubes (MWCNTs) and amorphous carbon nanowires (a-CNWs) were investigated at room and elevated temperatures with different irradiation doses. It is found that at room temperature, defects were introduced in MWCNTs under 70 keV N+ ion beam irradiation at a low dose of 1 × 1016 ions/cm2 while MWCNTs transformed into a-CNWs at a high dose of 7 × 1016 ions/cm2. At 1000 K, the 70 keV N+ ion beam irradiation of defective MWCNTs causes the curling of carbon clusters to an onion-like structure at a dose of 4 × 1016ions/cm2 and the formation of a low density onion-like structure at 7 × 1016 ions/cm2. Irradiation of the defective MWCNTs by 70 keV Ar+ ion at 1000 K and 7 × 1016 ions/cm2 leads to the formation of a high density onion-like structure. Irradiation of a-CNWs with 70 keV H+ ion at 1000 K gradually increases the fraction of material with a diamond structure with increasing dose from 1 × 1016 to 1 × 1017 ions/cm[2].