SD __ Nuclear Instruments and Methods in Physics Research B I 13 ( 1996) 244-247 __ @ NONI zyxwvutsrqponmlkjih B ELSEVIER Beam Interactions with Materials 8 Atoms Damage and sputtering of fullerene by low energy medium and heavy ions D. Fink a,*, L.T. Chadderton b, J. Vacik ‘, V. Hnatowicz ‘, F.C. Zawislak d, M. Behar d, P.L. Grande d a zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Huhn-Meitner-lnstitut. Glienicker Str. 100, D-14109 Berlin, Germuny b Division of Applied Physics, CSIRO, and Reseurch School of Physical Sciences, Institute of Advanced Studies, Australian National Uniuersity, GPO Box 4, Cunberru, ACT 2601. Australia ’ zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Nucieur Physics Institute, Czech Academy of Sciences, 25068 Rer near Prague, Czech Republic e Universidade Federal do Rio Grande do Sul, Institute de Fisica, Campus do Vale, 91500 Porto Alegre, Brazil zyxwvutsrqponmlkjih Abstract Fullerene is highly sensitive to energetic particle irradiation which leads to both structural changes and high sputter yields. In this work we restrict to the case of single-charged low energy heavy ion impact. Both fullerene sputtering and the fullerene fraction escaping from destruction decrease exponentially with increasing fluence. This points at the same underlying mechanism which is the fullerene target modification via nuclear interactions during statistically distributed ion impact. 1. Introduction In a recent review article [l] we discuss the present knowledge of fullerene destruction by ion beams. The main results are: (1) Fullerene destruction is due to both collisional and/or electronic energy transfer, depending on the projectile energy and specie under consideration. (2) In case of dominant collisional fullerene destruction, i.e. after low energy heavy ion irradiation at sufficiently small fluences @, fulierene destruction scales with the deposited nuclear energy density D, = @S, (S, = nuclear stopping power). (3) In case of dominant electronic energy transfer, given at sufficiently low fluences @ after high energy heavy ion irradiation, or after light ion irradiation at lower energies, the destruction yield appears to scale with the square of the deposited electronic energy density, De = (@ Se)2 (S, = electronic stopping power). (4) For “high” fluences - typically above some lOI to lOI3 ions/cm* - the saturating fullerene destruction can be explained on the basis of statistically distributed ion impact onto the target. We have further made first experiments on the sputter- ing of fullerene by single-charged heavy ions at low energies and high fluences [2,3], by looking at the im- planted ion depth profiles, which served us as markers for the surface recession under irradiation. The main results of * Corresponding author. Tel.: + 49 30 8062 3029; fax: + 49 30 8062 2293. these examinations are that (1) the sputtering yield de- creases with fluence @, and that (2) the sputter yields can be explained on the basis of statistically distributed ion impact onto the fullerene targets. This suggests that, in case of single-charged low energy medium and heavy ion impact onto fullerene, both effects - fullerene damage and sputtering - result from the same underly ing mechanism, which is collisional (“nuclear”~ energy transfer via statistically distributed ion impact. Such a correlation is well known since long for metallic or semiconducting targets, where there exists a simple relation between nuclear damage and sputtering. Therefore the above mentioned suggestion appears just as a natural expansion of the present knowledge to this new carbonaceous allotrope. Another such correlation might exist between electronic damage and sputtering of fullerene, however there does not yet exist a sufficient experimental data base to check for this possibility. There is a peculiar experimental complication in the case of fullerenes in comparison to other target materials, which results from the competition of an extremely high radiation sensitivity and an extremely high sputter yield of this material: As long as fullerene damage can be observed experimentally (e.g. by Raman spectrometry), the amount of sputtered material is still too little to be detected experi- mentally (e.g. by Rutherford backscattering, RBS), and when sputtering becomes measurable by e.g. RBS, the experimentally observable fullerene destruction has al- ready come to saturation. In other words, at present it appears to be nearly impossible to probe both fullerene 0168-583X/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 0168-583X(95)01391-1