Peking Univ, Inst Heavy Ion Phys, Beijing 100871, Peoples R China
; Inst High Energy Phys, Beijing 100081, Peoples R China
Highly oriented pyrolitic graphite (HOPG) samples were bombarded by different kinds of ions, including H, He, B, C, and Au, at an energy range from 530 keV to 4.5 MeV. After bombardment, the sample surfaces were observed with scanning tunneling microscopy. All these experimental results show that the energetic ions could cause observable protrusionlike damage on the HOPG surfaces. The ratio of the areal density of protrusion 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 phenomena is also discussed. (C) 1998 American Institute of Physics. [S0021-8979(98)06201-X].