STM observation of cluster size dependence of HOPG surface damages induced by energetic Sin and Gen clusters

Samples of highly oriented pyrolytic graphite (HOPG) were irradiated by Si n ( n = 1, 2, 3, 4, 5) with energy of 300 keV/atom and Ge n ( n = 1, 2, 3) with energy of 500 keV/atom at perpendicular incidence and at a fluence of 5 × 10 12 projectiles/cm 2 , respectively. The observations by scanning tunneling microscopy (STM) clearly show a non-linear effect of the average damage area on the surface induced by clusters of different size. The dependence of the relative radiation damage on the cluster size follows a n 1.47 law for Si n irradiation and a n 1.1 law for Ge n irradiation, respectively.