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

The effects of 11(+), 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 M'WCNTs under 70 keV N+ ion beam irradiation at a low dose of 1x 10(16) ions/cm(2) while MWCNTs transformed into a-CNWs at a high dose of 7x10(16) ions/cm(2). At 1 000 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 4x10(16) ions/cm(2) and the formation of a low density onion like structure at 7 x10(16) ions/cm(2). Irradiation of the defective MWCNTs by 70 keV Ar+ ion at 1 000 K and 7x10(16) ions/cm(2) leads to the formation of a high density onion like structure. Irradiation of a CNWs with 70 keV ion at 1 000 K gradually increases the fraction of material with a diamond structure with increasing dose from 1 x 10(16) to 1 x 10(17) ions/cm(2).