The changes in resistivity in fullerene(C-60) films subjected to 320-k
eV Xe ion irradiation are investigated as a function of ion dose. From
a comparison of this dependence with similar data on Xe irradiated di
amond and with data on C implanted fused quartz, it is concluded that
upon ion impact C-60 clusters completely disintegrate. This disintegra
tion releases about 60 carbon atoms which disperse among the remaining
intact C-60 spheres giving rise to hopping conductivity between isola
ted C atoms. The present finding may explain the negative results in t
he search for fullerenes conjectured to exist in instellar dust and ma
y establish limitations on the use of ion implantation to dope fullere
nes with the aim of synthesizing new forms of high-T-c superconductors
.