Local heating induced by single MeV C60 ion impacts

Gold and platinum nanoparticles of few-nm size were deposited on amorphous silicon oxide and amorphous silicon nitride films. These films were irradiated with 0.72 and 1.1 MeV C₆₀³⁺ ions. Local heating of these films induced by the single ion impact was evaluated by observing desorption of the nanoparticles from the target surfaces upon ion impact. It was found that the local heating at the exit surface is very sensitive to the film thickness. For thinner films, the observed local heating at the exit surface is enhanced compared to the entrance surface while the result is opposite for thicker films. The observed result can be well explained by the unified thermal spike model taking account of the broadening of the spatial distribution of constituent carbon ions during the passage across the film.