Study by HREELS of elementary reactions on graphite surface induced by Ar+ and H+ ion bombardment

We used high-resolution electron energy loss spectroscopy to study the effect of Ar+ and H+ ion bombardment on a highly oriented pyrolitic graphite sample. Ion beam fluences in the range 1O(14) to 4 x 10(16) cm(-2) were used with an ion impact energy of 5 keV. For a low ion fluence (of Ar+ and H+), the low energy pi-plasmon of graphite is shifted toward lower energies, while for higher fluences (>10(16) cm(-2)), the plasmon vanishes behind an increasing background. In the case of H+ ion bombardment, supplementary chemical reactions take place on the surface, and we report C-H stretching modes induced by the bombardment. We relate the above observations with structural and chemical modifications induced by the ion bombardment and compare with previous results. (C) 2000 Published by Elsevier Science B.V. All rights reserved.