ENERGY-DISTRIBUTIONS AND YIELDS OF SPUTTERED C-2 AND C-3 CLUSTERS

The sputtering of carbon materials by energetic particles leads mainly to the emission of monoatomic carbon, but also to C-2 and C-2 cluster s. Time-of-flight measurements were performed to determine the energy distributions of C-1, C-2 and C-3 sputtered from graphite during 5 keV Ne+ impact. All energy distributions are characterized by the Thompso n distribution with a surface binding energy of 7.5 eV for C, 3.5 eV f or C-2 and 0.8 eV for C-3. Using these distribution data the flux rati os of sputtered C-2 and C-3 to sputtered C can be determined to be 0.0 6 for C-2/C and 0.03 for C-3/C by 5 keV Ar+ impact, 0.05 for C-2/C and 0.02 for C-3/C by 5 keV Ne+ impact and 0.06 for C-2/C and 0.01 for C- 3/C by 5 keV He+ impact, respectively. Thus, 11% of all sputtered carb on is emitted as C-2 and in the case of 5 keV Ar+ impact 9% as C-3.