STUDIES ON SURFACE DAMAGE-INDUCED BY ION-BOMBARDMENT

Highly oriented pyrolitic graphite (HOPG) samples were bombarded by di fferent kinds of ions, including H, He, B, C, and Au, at an energy ran ge from 530 keV to 4.5 MeV. After bombardment, the sample surfaces wer e observed with scanning tunneling microscopy. All these experimental results show that the energetic ions could cause observable protrusion like damage on the HOPG surfaces. The ratio of the areal density of pr otrusion to the ion dose increases with the nuclear energy loss and is in the range of 10(-5) to 2. The possible mechanism of these phenomen a is also discussed. (C) 1998 American Institute of Physics. [S0021-89 79(98)06201-X].